Electric axle device for vehicle

Abstract

To secure fastening strength and bending strength.SOLUTION: An electric axle device 100 for a vehicle includes: an electric motor 3; a decelerator 2 connected to an output side of the electric motor; a differential device 5 connected to an output side of the decelerator; left and right axle shafts 21 connected to an output side of the differential device; left and right axle shaft casings 30 that accommodate the left and right axle shafts, respectively; a common casing 31 that is common to the decelerator and the differential device, the common casing being sandwiched between the left and right axle shaft casings and fixed to the left and right axle shaft casings with bolts 32; and a reinforcing member 33 disposed outside the common casing and connecting the left and right axle shaft casings.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electric axle device for a vehicle.

Background Art

[0002] In a rigid axle suspension system adopted in vehicles such as trucks, an axle housing that houses a differential device is connected to a vehicle body via a spring such as a leaf spring. In recent years, an example has been seen in which a speed reducer and an electric motor are attached to this axle housing to form an electric axle device for a vehicle. By using this electric axle device for a vehicle, an existing vehicle can be electrified relatively easily.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when using a general axle housing such as a banjo type, there are problems such as restrictions on gear ratio design.

[0005] Therefore, from the viewpoint of ensuring design freedom, etc., this general axle housing is divided into a central part that houses a differential device and left and right parts that house left and right axle shafts, and a casing common to a speed reducer and a differential device is bolted and fixed to the left and right parts. This has been considered.

[0006] However, with this structure, ensuring the fastening strength of the casing and the left and right parts and the bending strength of the entire casing and the left and right parts becomes a problem.

[0007] Therefore, the present disclosure has been made in view of such circumstances, and an object thereof is to provide an electric axle device for a vehicle that can ensure fastening strength and bending strength.

Means for Solving the Problems

[0008] According to one aspect of the present disclosure, an electric motor, a speed reducer connected to the output side of the electric motor, a differential device connected to the output side of the speed reducer, left and right axle shafts connected to the output side of the differential device, left and right axle shaft casings that respectively house the left and right axle shafts, a common casing that is common to the speed reducer and the differential device, is disposed between the left and right axle shaft casings, and is fixed to the left and right axle shaft casings with bolts, a reinforcing member disposed outside the common casing and connecting the left and right axle shaft casings, and an electric axle device for a vehicle characterized by including the above.

[0009] Preferably, brackets are fixed to the left and right axle shaft casings by welding, and both ends of the reinforcing member are fixed to the left and right brackets by welding.

[0010] Preferably, the reinforcing member is formed of an elongated metal plate that extends in the left - right direction and is formed in a hat shape.

[0011] Preferably, the reinforcing member is disposed below the common casing.

[0012] Preferably, the reinforcing member is disposed above the common casing.

[0013] Preferably, the reinforcing member is disposed on the rear side of the common casing.

[0014] Preferably, the common casing extends forward from a position between the left and right axle shaft casings.

[0015] Preferably, the common casing is a casting formed of aluminum or an aluminum alloy.

[0016] Preferably, the left and right axle shaft casings have flanges attached to the common casing by the bolts.

[0017] Preferably, both ends of the reinforcing member are fixed to the left and right flanges.

[0018] Preferably, the reinforcing member has a main body portion extending in the left - right direction and formed in an arc - shaped cross - section, and hook portions extending radially inward from the left and right ends of the main body portion. The flange has a disk - shaped main body portion and a protruding portion provided to protrude radially outward on the outer peripheral portion of the main body portion. The main body portion is overlapped on the arc - shaped outer peripheral surface of the protruding portion, and the hook portion is overlapped on the left - right direction outer side surface of the protruding portion.

[0019] Preferably, the hook portion is fixed to the left - right direction outer side surface of the protruding portion by bolts.

Advantages of the Invention

[0020] According to the present disclosure, fastening strength and bending strength can be ensured.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that it should be noted that the present disclosure is not limited to the following embodiments.

[0023] [First Embodiment] FIGS. 1 to 3 show an electric axle device according to a first embodiment of the present disclosure. FIG. 1 is a rear view, FIG. 2 is a plan view, and FIG. 3 is a right side view. FIG. 4 is a skeleton view schematically showing the internal structure of the electric axle device. For convenience, the directions of front, rear, left, right, up, and down are defined as shown in the drawings. These directions generally correspond to the directions of the vehicle.

[0024] The electric axle device 100 is applied to a vehicle and is configured to be applied to a truck in this embodiment. However, the type of vehicle is arbitrary. The electric axle device 100 is configured to drive the left and right rear wheels of the vehicle and constitutes a part of a rigid axle (or axle suspension type) suspension system for the rear wheels.

[0025] The electric axle device 100 includes a motor 3, a speed reducer 2 connected to the output side of the motor 3, a differential device 5 connected to the output side of the speed reducer 2, left and right axle shafts 21 (21L, 21R, see FIG. 4) connected to the output side of the differential device 5, and left and right axle shaft casings 30 (30L, 30R) that house the left and right axle shafts 21 respectively.

[0026] The electric axle device 100 also includes a common casing 31 that is common to the speed reducer 2 and the differential device 5. The common casing 31 is an integration of the casing of the speed reducer 2 and the casing of the differential device 5. The common casing 31 is disposed sandwiched between the left and right axle shaft casings 30 and is fixed to the left and right axle shaft casings 30 with a plurality of bolts 32. Only the center lines of the bolts 32 are shown as virtual lines in the figure (the same applies hereinafter).

[0027] The left and right axle shaft casings 30 form the left and right parts of a general axle housing. The common casing 31 forms the central part of a general axle housing.

[0028] The common casing 31 extends forward from a position between the left and right axle shaft casings 30. The common casing 31 is a casting formed of aluminum or an aluminum alloy. On the other hand, the left and right axle shaft casings 30 are made of iron and are assembled by welding a plurality of parts.

[0029] In the case of this embodiment, the common casing 31 is not common with the motor 3. The casing 29 of the motor 3 is fixed to the common casing 31 with a plurality of bolts 35 (see FIG. 4). The motor 3 includes electrical components (not shown) such as a stator and a rotor housed in the casing 29.

[0030] As shown in FIG. 4, the speed reducer 2 includes a gear mechanism 6 housed in a common casing 31. The gear mechanism 6 of the present embodiment is configured to reduce the rotational driving force of the electric motor 3 in three stages and transmit it to the differential device 5.

[0031] The gear mechanism 6 includes a drive shaft 10 coaxially connected to the output shaft 9 of the electric motor 3, a first reduction shaft 11A and a second reduction shaft 11B provided in parallel with the drive shaft 10, and a drive pinion gear 12 and a first spur gear 13A respectively attached to the drive shaft 10 and the first reduction shaft 11A and meshing with each other. The number of teeth of the first spur gear 13A is made larger than the number of teeth of the drive pinion gear 12.

[0032] The gear mechanism 6 also includes a first pinion gear 13B and a second spur gear 14A respectively attached to the first reduction shaft 11A and the second reduction shaft 11B and meshing with each other, and a second pinion gear 14B attached to the second reduction shaft 11B. The number of teeth of the second spur gear 14A is made larger than the number of teeth of the first pinion gear 13B.

[0033] The gear mechanism 6 also includes a plurality of bearings 15 fixed to the common casing 31 and rotatably supporting the drive shaft 10, the first reduction shaft 11A, and the second reduction shaft 11B respectively.

[0034] The differential device 5 includes a differential mechanism 1 housed in the common casing 31. The differential mechanism 1 includes a differential case 16, a plurality of bearings 17 fixed to the common casing 31 and rotatably supporting the differential case 16, and a differential spur gear 18 fixed to the differential case 16 and meshing with the second pinion gear 14B. The number of teeth of the differential spur gear 18 is made larger than the number of teeth of the second pinion gear 14B.

[0035] The differential mechanism 1 also includes a plurality of differential pinion gears 19 rotatably supported within a differential case 16, and left and right side gears 20 (20L, 20R) rotatably supported within the differential case 16 and meshed with the plurality of differential pinion gears 19. Left and right axle shafts 21 are coaxially connected to the left and right side gears 20, respectively.

[0036] The second pinion gear 14B and the differential spur gear 18 are parallel-axis gears (spur gears, helical gears, etc.). This makes manufacturing easier and improves vibration and noise performance compared to the case of using crossed-axis gears (bevel gears, etc.). Note that the other gears 12, 13A, 13B, 14A are also parallel-axis gears.

[0037] Alternatively, at least one of these gear sets may be configured with crossed-axis gears.

[0038] Let the center of the output shaft 9 of the electric motor 3 be the electric motor center C1. Also, let the center of the drive shaft 10 of the speed reducer 2 be the speed reducer center C2. Further, let the center of the axle shaft 21 be the axle shaft center C3. The electric motor center C1 and the speed reducer center C2 are coaxial, and the electric motor center C1, the speed reducer center C2, and the axle shaft center C3 are parallel to each other. The electric motor center C1, the speed reducer center C2, and the axle shaft center C3 extend in the left-right direction. The electric motor center C1 and the speed reducer center C2 are positioned in front of the axle shaft center C3.

[0039] The speed reducer 2 is arranged in front of the differential device 5, and the electric motor 3 is arranged in front of the differential device 5 and on the side (left side) of the speed reducer 2. This can make the entire electric axle device 100 compact.

[0040] As also shown in FIGS. 1 and 2, the common casing 31 is composed of split casings 34L and 34R which are formed by splitting it into two parts left and right. After the joints (joint surfaces) 35L and 35R of the split casings 34L and 34R perpendicular to the axle shaft center C3 are joined to each other, the split casings 34L and 34R are fixed to each other by a plurality of bolts 36. The joint positions of these joints 35L and 35R are set as the reference position C4 in the left-right direction.

[0041] In the left-right direction, the direction approaching the reference position C4 is defined as the inner side in the left-right direction or the inner side in the vehicle width direction, and the direction away from the reference position C4 is defined as the outer side in the left-right direction or the outer side in the vehicle width direction.

[0042] The left and right axle shaft casings 30 are generally symmetrically configured left and right, although their lengths in the left-right direction are slightly different.

[0043] The axle shaft casing 30 is formed in a cylindrical shape extending in the left-right direction. At the longitudinal intermediate part of the axle shaft casing 30, a hub flange 24 for connecting an axle hub (not shown) or the like and a spring bracket 25 for seating a suspension spring such as a leaf spring are integrally fixed by welding. The spring bracket 25 is located on the inner side in the vehicle width direction from the hub flange 24.

[0044] Among the axle shaft casings 30, the mounting part of the hub flange 24 and the part on the outer side in the vehicle width direction thereof are formed in a cylindrical shape with a circular cross section. Also, among the axle shaft casings 30, the part on the inner side in the vehicle width direction from the mounting part of the hub flange 24 has a rectangular cross section with rounded corners at the four corners and a certain front-rear width, as shown in FIGS. 5 and 6.

[0045] Among the axle shaft casings 30, the part on the inner side in the vehicle width direction from the spring bracket 25 gradually increases in height (vertical) dimension as it goes toward the inner side in the vehicle width direction, as shown in FIG. 1.

[0046] The spring bracket 25 is symmetrically mounted on the upper and lower surfaces of the axle shaft casing 30, respectively. The spring bracket 25 is formed by a U-shaped metal plate, specifically an iron plate, in a rear view as shown in Fig. 1. The upper spring bracket 25 is formed in a U shape with the lower side open, and the lower spring bracket 25 is formed in a U shape with the upper side open.

[0047] Since the upper and lower spring brackets 25 are vertically symmetric, only the upper spring bracket 25 will be described here. As shown in Fig. 5, the upper spring bracket 25 has a greater front-to-rear width than the axle shaft casing 30. And a recess 37 that fits onto the upper surface of the axle shaft casing 30 is formed on the lower end surface of the upper spring bracket 25. After the recess 37 is fitted onto the upper surface of the axle shaft casing 30, the upper spring bracket 25 is fillet welded to the axle shaft casing 30 and fixed.

[0048] As shown in Figs. 1 to 4, the left and right axle shaft casings 30 have disc-shaped flanges 38 (38L, 38R) that are attached to the common casing 31 by a plurality of bolts 32 at the inner ends in the vehicle width direction. The flange 38 is fixed to the axle shaft casing 30 by welding. After the common casing 31 and the flange 38 are joined together, these joints are fixed by a plurality of bolts 32. The bolts 32 are attached at equal intervals along the circumferential direction of the flange 38.

[0049] More specifically, the left flange 38L is fixed by bolts 32 to the left end (outer side in the vehicle width direction) of the left split casing 34L. Also, the right flange 38R is fixed by bolts 32 to the right end (outer side in the vehicle width direction) of the right split casing 34R.

[0050] The axle shaft casing 30 is assembled by integrating pre-divided components by welding. That is, the axle shaft casing 30 is composed of a cylindrical component 30A in which the hub flange 24 and the portion outside it in the vehicle width direction are integrated by welding, angular cylindrical components 30U and 30D that are located inside the hub flange 24 in the vehicle width direction and are divided into two parts vertically, and a flange 38, which are integrated by welding.

[0051] As shown in FIGS. 1 to 3, the electric axle device 100 includes an inverter 39 attached to the outer peripheral portion of the casing 29 of the electric motor 3. The inverter 39 is an electrical component for controlling the rotation of the electric motor 3 and is electrically connected to the electric motor 3 via a relatively short cable. In the case of this embodiment, the inverter 39 is formed in a flat rectangular box shape, is placed horizontally on the upper surface portion of the casing 29, and is fixed to the casing 29 by bolts (not shown). Thus, the weight of the inverter 39 is supported from below by the casing 29. The inverter 39 is arranged on the left side of the reference position C4 in the left-right direction.

[0052] The electric axle device 100 also includes a park lock actuator 40 attached to the outer peripheral portion of the common casing 31. The park lock actuator 40 meshes with a gear (for example, the drive pinion gear 12) of the gear mechanism 6 during operation to lock the gear and is for realizing an electric parking brake. The park lock actuator 40 is formed in a flat rectangular box shape smaller than the inverter 39, is placed horizontally on the upper surface portion of the common casing 31, and is fixed to the common casing 31 by bolts (not shown). Thus, the weight of the park lock actuator 40 is supported from below by the common casing 31.

[0053] The park lock actuator 40 is arranged to the immediate right of the inverter 39 straddling the reference position C4 in the left-right direction and on top of the front end portion of the common casing 31. Therefore, the park lock actuator 40 is arranged straddling the left and right split casings 34L and 34R.

[0054] The inverter 39 and the park lock actuator 40 are both arranged behind the foremost end of the common casing 31 and are arranged so as not to protrude forward of the common casing 31. Thereby, a compact electric axle device 100 can be realized.

[0055] Now, in the present embodiment, from the viewpoint of ensuring the degree of freedom in design and the like, the casings of the speed reducer 2 and the differential device 5 are integrated as a common casing 31, and the left and right axle shaft casings 30 are fastened and fixed to this common casing 31 with bolts 32.

[0056] However, with this structure, ensuring the fastening strength of the common casing 31 and the left and right axle shaft casings 30 and the bending strength of the entire common casing 31 and the left and right axle shaft casings 30 becomes a problem.

[0057] Therefore, in the present embodiment, in order to ensure such fastening strength and bending strength, a reinforcing member 33 is provided on the outside of the common casing 31 to connect the left and right axle shaft casings 30. This will be described below.

[0058] As shown in FIGS. 1 to 3, in the present embodiment, a plurality (specifically, three) of reinforcing members 33 are provided, including a lower reinforcing member 33D arranged below the common casing 31, an upper reinforcing member 33U arranged above the common casing 31, and a rear reinforcing member 33R arranged behind the common casing 31. These have the same configuration.

[0059] As shown in FIGS. 1, 3, and 6, the reinforcing member 33 extends in the left - right direction and is formed by an elongated metal plate formed in a hat shape in a rear view (FIG. 1). The cross - section of the reinforcing member 33 is a rectangle in which the thickness t is smaller than the width W. The material of the reinforcing member 33 is iron, and the reinforcing member 33 is formed by bending an elongated solid iron plate into a hat shape by press working or the like. The reinforcing member 33 is configured symmetrically about the left - right direction.

[0060] The lower reinforcing member 33D is formed in a hat shape convex downward, the upper reinforcing member 33U is formed in a hat shape convex upward, and the rear reinforcing member 33R is formed in a hat shape convex rearward. Thereby, the common casing 31 can be avoided and interference with the common casing 31 can be avoided.

[0061] In the present embodiment, brackets 41 are fixed to the left and right axle shaft casings 30 (30L, 30R) by welding, and both ends of the reinforcing member 33 are fixed to the left and right brackets 41 by welding.

[0062] The bracket 41 is configured in the same manner as the aforementioned spring bracket 25. The bracket 41 is formed of a U-shaped metal plate, specifically an iron plate, when viewed from the rear. The bracket 41 integrally has a flat plate portion 42 on which the reinforcing member 33 is seated and fixed, and a pair of leg portions 43 extending vertically from both left and right ends of the flat plate portion 42. The bracket 41 is attached at a position between the spring bracket 25 and the flange 38 in the axle shaft casing 30 and at a portion where the height dimension gradually changes.

[0063] The width W1 of the bracket 41 is made equal to the width W of the reinforcing member 33. These widths W and W1 are slightly smaller than the front-rear width W2 of the axle shaft casing 30. Since the height H2 of the axle shaft casing 30 is larger than the front-rear width W2, the widths W and W1 of the reinforcing member 33 and the bracket 41 are smaller than the height H2 of the axle shaft casing 30. The bracket 41 and the reinforcing member 33 are fixed such that both end faces in the W1 and W directions are at the same position.

[0064] Three brackets 41 are provided for each of the left and right axle shaft casings 30 corresponding to the three reinforcing members 33.

[0065] Regarding the lower reinforcement member 33D, the bracket 41 is attached to the lower surface portions of the left and right axle shaft casings 30. The bracket 41 is arranged in a U-shaped configuration with an open upper side. Shallow recesses 44 conforming to the shape of the lower surface portions of the axle shaft casings 30 are formed on the upper end surface portions of the pair of leg portions 43. After the recesses 44 are fitted to the lower surface portions of the axle shaft casings 30, the leg portions 43 of the bracket 41 are fillet welded to the lower surface portions of the axle shaft casings 30 and fixed. In the fixed state, the lower reinforcement member 33D and the bracket 41 do not protrude forward and backward from the axle shaft casing 30.

[0066] Regarding the upper reinforcement member 33U, since it is the same as the case of the lower reinforcement member 33D except that it is upside down, the description is omitted.

[0067] Regarding the rear reinforcement member 33R, it is the same as the configuration in which the orientation of the configuration regarding the lower reinforcement member 33D is changed by 90° rearward around the axle shaft center C3. However, on the rear surface portions of the left and right axle shaft casings 30, there are flat surfaces having a height dimension larger than the width W1 of the bracket 41. Therefore, the aforementioned recesses 44 are not provided on the front end surface portions of the pair of leg portions 43 of the bracket 41, and after the flat front end surface portions of the leg portions 43 are seated on the flat rear surface portions of the axle shaft casings 30, the leg portions 43 are fillet welded to the rear surface portions of the axle shaft casings 30 and fixed. In the fixed state, the rear reinforcement member 33R and the bracket 41 do not protrude upward and downward from the axle shaft casing 30.

[0068] As shown in FIGS. 1 to 3, the positions of the left end surface portions in the left - right direction of each reinforcement member 33 are the same as the positions of the left end surface portions of the left bracket 41. Also, the positions of the right end surface portions in the left - right direction of each reinforcement member 33 are the same as the positions of the right end surface portions of the right bracket 41.

[0069] The lower reinforcement member 33D, the upper reinforcement member 33U, and the rear reinforcement member 33R are arranged at equal intervals of 90° in the circumferential direction around the axle shaft center C3.

[0070] The lower reinforcing member 33D and the upper reinforcing member 33U are horizontally arranged so that the width W direction thereof coincides with the front-rear direction. Thereby, the projected areas of the lower reinforcing member 33D and the upper reinforcing member 33U when viewed from the front are minimized, and an increase in air resistance caused by these can be suppressed to a minimum.

[0071] Further, the rear reinforcing member 33R is vertically arranged so that the width W direction thereof coincides with the vertical direction. Thereby, the projected area of the rear reinforcing member 33R when viewed from the front becomes the largest. However, the rear reinforcing member 33R is arranged hidden behind the common casing 31 and is not directly hit by the traveling wind. Therefore, there is substantially no increase in air resistance due to the rear reinforcing member 33R.

[0072] In the present embodiment, the common casing 31 extends forward from a position between the left and right axle shaft casings 30. Therefore, no reinforcing member 33 is provided in front of the common casing 31, and the reinforcing members 33 are provided below, above, and behind the common casing 31 other than that.

[0073] Thus, in the present embodiment, the left and right axle shaft casings 30 are connected by the reinforcing members 33. Therefore, the fastening strength of the common casing 31 and the left and right axle shaft casings 30 can be enhanced, and the bending strength of the common casing 31 and the left and right axle shaft casings 30 as a whole can be enhanced. Therefore, it is possible to ensure sufficient fastening strength and bending strength. In addition, in the present embodiment, the torsional strength of the common casing 31 and the left and right axle shaft casings 30 as a whole can also be enhanced.

[0074] In the present embodiment, since a plurality of reinforcing members 33 are provided, the fastening strength, bending strength, and torsional strength can be further ensured. Further, since the lower reinforcing member 33D, the upper reinforcing member 33U, and the rear reinforcing member 33R are arranged in a well-balanced manner in the circumferential direction around the axle shaft center C3, a suitable strength balance can be obtained.

[0075] Further, the reinforcing member 33 is disposed outside the common casing 31 with a gap therebetween. There is also a gap between the three reinforcing members 33D, 33U, and 33R. Therefore, outside air and running wind can be directly applied to the common casing 31 through these gaps. As a result, the common casing 31 can be sufficiently air-cooled.

[0076] Note that the heat of the common casing 31 is transmitted to the reinforcing member 33 through the axle shaft casing 30 and the bracket 41, and the heat of the reinforcing member 33 is dissipated to the outside air. Therefore, the common casing 31 can also be air-cooled through the reinforcing member 33.

[0077] Also, in the present embodiment, since the lower reinforcing member 33D serves to block the spring stone during running, the common casing 31 and the axle shaft casing 30 can be protected from the spring stone. Further, the lower reinforcing member 33D can be used as a jack-up point during vehicle maintenance.

[0078] In the present embodiment, since the reinforcing member 33 is attached to the axle shaft casing 30 via the bracket 41, the attachment of the reinforcing member 33 becomes easy and the attachment position of the reinforcing member 33 can be adjusted by the bracket 41. Therefore, a common reinforcing member 33 can be used as the three reinforcing members 33D, 33U, and 33R, and cost reduction can be achieved by commonizing parts. In fact, such commonization is being carried out in the present embodiment.

[0079] In the present embodiment, the inverter 39 is attached to the outer peripheral portion (particularly the upper surface portion) of the casing 29 of the electric motor 3. Usually, the inverter is attached to the vehicle body side of the vehicle and connected to the electric motor via a relatively long cable. However, in this case, the relatively long cable has to be routed along a predetermined route, which poses a difficulty in terms of assemblability.

[0080] Also, when the vehicle is running, the motor moves up and down with respect to the vehicle body. On the other hand, the inverter is fixed to the vehicle body side. Therefore, the cable must always be deformed following the up and down movement of the motor with respect to the inverter, and there is a risk that the cable will be damaged or disconnected. Also, an unnecessary load is applied to the connectors that connect the cable to the inverter and the motor, and there is a risk that the connector connection part will be damaged. All of these will lead to a decrease in reliability.

[0081] However, in the present embodiment, the inverter 39 is attached to the outer peripheral portion of the casing 29 of the motor 3. By doing so, the cable connecting the inverter 39 and the motor 3 can be shortened, the cable routing becomes easy, and the assemblability can be improved.

[0082] Also, when the motor 3 moves up and down with respect to the vehicle body during vehicle running, the inverter 39 also moves up and down integrally following the motor 3. For this reason, no relative movement occurs between the inverter 39 and the motor 3, and deformation of the cable during up and down movement can be prevented. Therefore, it is possible to prevent the cable from being damaged or disconnected due to the relative movement between the two. Also, an unnecessary load does not need to be applied to the connectors that connect the cable to the inverter 39 and the motor 3, and damage to the connector connection part can also be prevented. In this way, the reliability can be greatly improved.

[0083] [Second Embodiment] Next, a second embodiment of the present disclosure will be described. Note that the description of the same parts as in the first embodiment will be omitted, and hereinafter, the differences from the first embodiment will be mainly described.

[0084] Figs. 7 to 9 show an electric axle device 200 according to the second embodiment, Fig. 7 is a rear view, Fig. 8 is a plan view, and Fig. 9 is a right side view.

[0085] As shown in Figs. 7 to 9, also in the present embodiment, a plurality (specifically, three) of reinforcing members 33 are provided, including a lower reinforcing member 33D disposed below the common casing 31, an upper reinforcing member 33U disposed above the common casing 31, and a rear reinforcing member 33R disposed behind the common casing 31.

[0086] In the case of this embodiment, both ends of the reinforcing member 33 are fixed to the left and right flanges 38 (38L, 38R). Therefore, the bracket 41 in the first embodiment is omitted, whereby the number of parts and the manufacturing cost can be reduced, and the manufacturing can be facilitated.

[0087] As shown in FIG. 10, the flange 38 has, in addition to the disc-shaped main body portion 50 similar to that of the first embodiment, a protruding portion 51 provided so as to protrude radially outward on the outer peripheral portion of the main body portion 50. Here, the radial direction is the radial direction with reference to the axle shaft center C3. The reinforcing member 33 is overlapped and attached to this protruding portion 50. Corresponding to the three reinforcing members 33, three protruding portions 51, that is, a lower protruding portion 51D, an upper protruding portion 51U, and a rear protruding portion 51R are provided. The protruding portion 51 has an arcuate outer peripheral surface when viewed from the axial direction with reference to the axle shaft center C3. And the arcuate outer peripheral surfaces of the lower protruding portion 51D, the upper protruding portion 51U, and the rear protruding portion 51R have the same radius with respect to the axle shaft center C3.

[0088] In the circumferential direction with reference to the axle shaft center C3, let the phase centers of the lower protruding portion 51D, the upper protruding portion 51U, and the rear protruding portion 51R be PD, PU, PR respectively, and the phase widths be WD, WU, WR respectively. The phase centers PD, PU, PR of these protruding portions 51D, 51U, 51R are approximately equally spaced and are separated from each other by about 90°. Also, the phase centers PD, PU of the lower protruding portion 51D and the upper protruding portion 51U are shifted clockwise in the drawing by predetermined angles θD, θU with respect to the vertical axis. The phase center PR of the rear protruding portion 51R is also shifted clockwise in the drawing by a predetermined angle θR with respect to the front-rear axis. θD, θU, θR are angles at approximately the same level. Thereby, when the electric axle device 200 is mounted in a rear-tilted state, with respect to the axle shaft center C3, the phase center PD of the lower protruding portion 51D is positioned almost directly below, the phase center PU of the upper protruding portion 51U is positioned almost directly above, and the phase center PR of the rear protruding portion 51R is positioned almost directly behind.

[0089] The phase widths WU and WR of the upper protruding portion 51U and the rear protruding portion 51R are substantially equal. On the other hand, the phase width WD of the lower protruding portion 51D is larger than those phase widths WU and WR, and although it is arbitrary, it is preferably 90° or in the vicinity thereof. In the present embodiment, the phase width WD is 90°, and among them, the portion in front of the vertical axis passing through the axle shaft center C3 is 25°, and the portion behind it is 65°.

[0090] As shown in detail in FIGS. 10 and 11, the reinforcing member 33 has a main body portion 52 extending in the left - right direction and formed in an arc - shaped cross - section (see FIG. 10), and hook portions 53 extending radially inward (with reference to the axle shaft center C3) from the left and right ends of the main body portion 52. The reinforcing member 33 is formed of a metal plate. Specifically, the material of the reinforcing member 33 is iron, and an elongated solid iron plate is formed into an arc - shaped cross - section by pressing or the like, and both ends thereof are bent at right angles to form the reinforcing member 33. The reinforcing member 33 is configured symmetrically about the left - right direction.

[0091] By attaching such a reinforcing member 33 to the protruding portion 51, similar to the hat - shaped reinforcing member 33 of the first embodiment, the common casing 31 can be avoided, and interference with the common casing 31 can be prevented.

[0092] The main body portion 52 of the reinforcing member 33 is overlapped with the arc - shaped outer peripheral surface of the protruding portion 51. Also, the left and right hook portions 53 of the reinforcing member 33 are overlapped with the outer - side surfaces in the left - right direction of the protruding portion 51 of the left and right flanges 38L and 38R. That is, the reinforcing member 33 is fitted across these protruding portions 51 so as to sandwich the protruding portion 51 of the left and right flanges 38L and 38R.

[0093] On the back surface (the radially inner surface) of the main body portion 52, a relatively shallow groove 54 for fitting the outer peripheral portion of the protruding portion 51 is formed at a location adjacent to the hook portion 53. Thereby, the position of the reinforcing member 33 with respect to the flange 38 can be accurately positioned in the left - right direction, and the rigidity after attachment of the reinforcing member 33 can be improved.

[0094] The hook portion 53 is fixed to the left and right direction outer side surfaces of the protruding portion 51 by bolts 55. That is, bolt insertion holes 56 are provided penetrating through the hook portion 53, and screw holes 57 are provided penetrating through the protruding portion 51. The bolt 55 is inserted into the bolt insertion hole 56 from the left and right direction outer side and tightened to the screw hole 57. Thereby, the reinforcing member 33 is detachably fixed to the flanges 38L and 38R.

[0095] A plurality of such bolt fixing locations are provided. Two locations are provided for the upper reinforcing member 33U and the rear reinforcing member 33R, and four locations are provided for the lower reinforcing member 33D.

[0096] As shown in FIG. 10, the lower reinforcing member 33D, the upper reinforcing member 33U, and the rear reinforcing member 33R have the same phase centers PD, PU, PR and phase widths WD, WU, WR as the lower protruding portion 51D, the upper protruding portion 51U, and the rear protruding portion 51R. Therefore, the phase centers PD, PU, PR and phase widths WD, WU, WR of the protruding portions 51D, 51U, 51R can be equivalently referred to as the phase centers PD, PU, PR and phase widths WD, WU, WR of the reinforcing members 33D, 33U, 33R.

[0097] The phase widths WU, WR of the upper reinforcing member 33U and the rear reinforcing member 33R are substantially equal. On the other hand, the phase width WD of the lower reinforcing member 33D is larger than those phase widths WU, WR, and although it is arbitrary, it is preferably 90° or in the vicinity thereof. In the present embodiment, the phase width WD is 90°, and among them, the portion in front of the vertical axis passing through the axle shaft center C3 is 25°, and the portion behind it is 65°.

[0098] By increasing the phase width WD of the lower reinforcing member 33D in this way, the pebbles during running can be blocked in a wide range by the lower reinforcing member 33D. Further, when the lower reinforcing member 33D is used as a jack-up point, the load applied to the lower reinforcing member 33D can be dispersed over a wide range.

[0099] In addition, the thickness tD of the main body portion 52 of the lower reinforcing member 33D is larger than the thicknesses tU and tR of the main body portions 52 of the upper reinforcing member 33U and the rear reinforcing member 33R. Therefore, the rigidity of the lower reinforcing member 33D can be increased, making it suitable as a jacking point.

[0100] When the vehicle is mounted, a jack is applied near the phase center PD of the lower reinforcing member 33D. In this embodiment, there are no bolts 55 in the region near the phase center PD. Therefore, deformation of the bolt 55 due to the load during jacking can be suppressed.

[0101] Note that the thicknesses tU and tR of the main body portions 52 of the upper reinforcing member 33U and the rear reinforcing member 33R are equal. The upper reinforcing member 33U and the rear reinforcing member 33R may be made of the same part and shared. Thereby, the manufacturing cost can be reduced.

[0102] The effects of this embodiment are basically the same as those of the first embodiment. In addition to this, in this embodiment, since the reinforcing member 33 is fixed to the flange 38, the bracket 41 of the first embodiment can be omitted, and cost reduction and easier manufacturing can be achieved by reducing the number of parts.

[0103] Also, in the first embodiment, the widths W of the reinforcing members 33D, 33U, and 33R are limited to some extent by the width W1 of the bracket 41 (see FIG. 6). However, in this embodiment, there is no such limitation on the phase widths WD, WU, and WR of the reinforcing members 33D, 33U, and 33R. Moreover, compared with the total of the widths W1 of the brackets 41 in the first embodiment, the total peripheral length of the flange 38 in this embodiment is significantly larger. Therefore, the phase widths WD, WU, and WR of the reinforcing members 33D, 33U, and 33R in this embodiment can be made larger than the widths W of the reinforcing members 33D, 33U, and 33R in the first embodiment. Thus, in this embodiment, the fastening strength and the bending strength can be enhanced more than in the first embodiment. In fact, the phase width WD of the lower reinforcing member 33D in this embodiment is significantly larger than the width W of the lower reinforcing member 33D in the first embodiment.

[0104] In addition, since the reinforcing member 33 has a main body portion 52 with an arcuate cross section and hook portions 53 at the left and right ends of the main body portion 52, the rigidity of the reinforcing member 33 can be increased, which is more advantageous for ensuring the fastening strength and the bending strength.

[0105] By providing the protruding portion 51 on the flange 38 and overlapping the main body portion 52 of the reinforcing member 33 on its outer peripheral surface, the reinforcing member 33 can be separated radially outward from the common casing 31, and their interference can be preferably prevented.

[0106] By overlapping the left and right hook portions 53 on the left and right outer side surfaces in the left - right direction of the left and right protruding portions 51, the reinforcing member 33 can be accurately positioned in the left - right direction with respect to the left and right flanges 38.

[0107] By fixing the left and right hook portions 53 to the left and right outer side surfaces in the left - right direction of the left and right protruding portions 51 with bolts 55, the hook portions 53 can be firmly and easily fixed. In addition, the opening and closing operations of the left and right flanges 38 during bending of the electric axle device 200 can be restrained by the reinforcing member 33. In addition, the reinforcing member 33 can be detached and replaced in case of damage or the like.

[0108] As described above, the embodiments of the present disclosure have been described in detail, but various other embodiments and modifications of the present disclosure are conceivable.

[0109] For example, the reinforcing member 33 may have a structure other than those described above. The reinforcing member 33 of the first embodiment may have other cross - sectional shapes (such as circular) or may have a hollow structure instead of being solid. Therefore, the reinforcing member 33 may be formed by a circular shaft, a square shaft, a circular cylinder, a square cylinder, or the like.

[0110] Similarly, the axle shaft casing 30 may also have a structure other than those described above. For example, the cross - sectional shape of the portion inside the vehicle width direction from the hub flange 24 may be circular or elliptical, etc. Also, accordingly, the shapes of the seating surfaces of the spring bracket 25 and the bracket 41 may be changed.

[0111] In the first embodiment, the reinforcing member 33 may be directly welded to the axle shaft casing 30 without passing through the bracket 41.

[0112] The number of the reinforcing members 33 can be changed, and one or two reinforcing members may be provided, or four or more reinforcing members may be provided. For example, only one or two of the lower reinforcing member 33D, the upper reinforcing member 33U, and the rear reinforcing member 33R may be provided.

[0113] In the first embodiment, if possible, the reinforcing member 33 may be fixed to the bracket 41 or the axle shaft casing 30 with bolts.

[0114] In the second embodiment, if possible, both left and right ends of the reinforcing member 33 may be fixed to the left and right flanges 38L and 38R by welding.

[0115] The embodiments of the present disclosure are not limited to the foregoing embodiments, and all modifications, application examples, and equivalents included in the idea of the present disclosure defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be construed in a limited manner, and it is possible to apply the present disclosure to any other technology belonging to the scope of the idea of the present disclosure.

Description of Reference Numerals

[0116] 2 Reducer 3 Motor 5 Differential device 21 Axle shaft 30 Axle shaft casing 31 Common casing 32 Bolt 33 Reinforcing member 33D Lower reinforcing member 33U Upper reinforcing member 33R Rear reinforcing member 38 Flange 41 Bracket 50 Main body part 51 Protrusion 52 Main body part 53 Hook part 55 volts 100, 200 Electric axle device

Claims

1. An electric motor; A reducer connected to an output side of the electric motor; A differential device connected to an output side of the reducer; left and right axle shafts connected to an output side of the differential device; left and right axle shaft casings accommodating the left and right axle shafts, respectively; a common casing common to the reduction gear and the differential device, the common casing being sandwiched between the left and right axle shaft casings and fixed to the left and right axle shaft casings with bolts; a reinforcing member disposed on an outer side of the common casing and connecting the left and right axle shaft casings; An electric axle device for a vehicle comprising:

2. Brackets are fixed to the left and right axle shaft casings by welding, and both ends of the reinforcing member are fixed to the left and right brackets by welding. The electric axle device for a vehicle according to claim 1 .

3. The reinforcing member is formed of a thin, hat-shaped metal plate extending in the left-right direction. The electric axle device for a vehicle according to claim 1 .

4. The reinforcing member is disposed below the common casing. The electric axle device for a vehicle according to claim 1 .

5. The reinforcing member is disposed on the upper side of the common casing. The electric axle device for a vehicle according to claim 1 .

6. The reinforcing member is disposed on the rear side of the common casing. The electric axle device for a vehicle according to claim 1 .

7. The common casing extends forward from a position between the left and right axle shaft casings. The electric axle device for a vehicle according to claim 1 .

8. The common casing is a casting made of aluminum or an aluminum alloy. The electric axle device for a vehicle according to claim 1 .

9. The left and right axle shaft casings have flanges that are attached to the common casing by the bolts. The electric axle device for a vehicle according to claim 1 .

10. Both ends of the reinforcing member are fixed to the left and right flanges. The electric axle device for a vehicle according to claim 9.

11. The reinforcing member has a main body portion extending in the left-right direction and formed to have an arc-shaped cross section, and hook portions extending radially inward from left and right ends of the main body portion, The flange has a disk-shaped main body and a protrusion provided on an outer periphery of the main body so as to protrude radially outward, The main body is placed on an arc-shaped outer peripheral surface of the protruding portion, and the hook is placed on an outer side surface of the protruding portion in the left-right direction. The electric axle device for a vehicle according to claim 10.

12. The hook portion is fixed to the outer side surface of the protrusion in the left-right direction by a bolt. The electric axle device for a vehicle according to claim 11.

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