Engine unit assembly structure in a vehicle

Abstract

An engine unit mounting structure comprises an integrally formed component formed by casting and an engine unit provided on an inside of the component in the vehicle width direction, wherein the component includes an upright wall section having a through-hole through which a bolt passes and which points in the vehicle width direction towards the engine unit, and a rib projecting to a predetermined height on an outer surface of the upright wall section towards an outside in the vehicle width direction in the vicinity of the through-hole, and wherein the engine unit has a mounting hole, the downstream side of which, in a bolt mounting direction, is an internally threaded section and the upstream side of which, in the bolt mounting direction, is an enlarged section whose inner diameter is larger than an outer diameter of a bolt shank.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to an engine unit mounting structure in a vehicle. 2. Description of the state of the art

[0002] A known arrangement exists in which the components comprising a vehicle body, including the shapes of the individual parts, are integrally formed (see, for example, Japanese patent application JP 2021 - 127 097 A). SUMMARY OF THE INVENTION

[0003] Nowadays, vehicles such as battery-powered electric vehicles are equipped with a motor unit. This motor unit has a housing made of metal, such as an aluminum alloy. To attach the motor unit to a component of the vehicle body, a bolt, threaded stud, or screw is inserted (tightened) into an internal threaded section formed in the housing. If the bolt is inserted at an angle into the internal threaded section of the aluminum housing, it damages the thread, and the bolt cannot be tightened. Therefore, a worker first loosely screws the bolt into the internal threaded section by hand and then uses an impact wrench to fully tighten the bolt.

[0004] On the other hand, there is a vehicle body component known as a "gigacast component," which is manufactured by integrally forming a multitude of parts through casting using a metal such as an aluminum alloy or similar, using a casting technology called "gigacasting." To reinforce the gigacast component, a multitude of ribs can be formed, projecting to a predetermined height. If the reinforcing rib is located near a through-hole for inserting the bolt to attach the engine unit to the gigacast component, it becomes difficult for the worker to reach the through-hole. That is, it becomes difficult for the worker to manually screw the bolt through the through-hole into the internal threaded section of the engine unit.

[0005] In a situation where the worker cannot loosely screw the bolt into the internal threaded section by hand and instead has to use an impact wrench to screw (tighten) the bolt directly into the internal threaded section, and the bolt is inserted at an angle, the bolt damages the internal threaded section, and consequently, the bolt cannot be screwed in (tightened). Therefore, concerns exist regarding the direct fastening of bolts or screws with an impact wrench when attaching the motor unit to the Gigacast component.

[0006] Accordingly, the object of the present invention is to provide an engine unit mounting structure in a vehicle in which there are no concerns regarding the screw fastening when an engine unit is attached to a component that is integrally formed by casting, even if a rib projecting to a predetermined height is formed near a through-hole for inserting a bolt into the component.

[0007] To solve the above-mentioned problem, an engine unit mounting structure in a vehicle according to a first aspect of the present invention comprises an integrally formed component by casting, which forms both sides of a front part of a vehicle body or both sides of a rear part of the vehicle body, and an engine unit which is provided on an inside of the component in the vehicle width direction and which drives the wheels, wherein the component has an upright wall section with a through hole through which a bolt ora screw is guided for fastening the motor unit and faces the motor unit in the vehicle width direction, and comprises a rib that projects in the vehicle width direction to an outside in the vicinity of the through-hole on an outer surface of the upright wall section up to a predetermined height, and the motor unit has a fastening hole, the downstream side of which is an internally threaded section in a bolt fastening direction and the upstream side of which is an enlarged section in the bolt fastening direction, the inner diameter of which is larger than the outer diameter of a bolt shank, and which is opened according to the through-hole.

[0008] According to the first aspect of the invention, the component forming both sides of the front part of the vehicle body or both sides of the rear part of the vehicle body is formed in one piece by casting, and the motor unit for driving the wheels is provided on the inside of the component in the vehicle width direction. The component has an upright wall section facing the motor unit in the vehicle width direction, and the upright wall section has the through-hole through which the bolt for fastening the motor unit is inserted. The rib is provided on the outer surface of the upright wall section near or surrounding the through-hole, so that it projects outwards in the vehicle width direction to a predetermined height. The motor unit also has mounting holes that are configured corresponding to the through-hole of the component.The mounting hole has an internal threaded section on the downstream side in the bolt mounting direction and an enlarged section with an inner diameter that is larger than the outer diameter of the bolt shank on the upstream side in the bolt mounting direction.

[0009] Accordingly, a rib is formed in the vicinity of the through-hole for inserting the bolt into the integrally formed, cast component. This rib projects to a predetermined height (to a height that makes it difficult for the worker to reach the through-hole by hand). Even if the bolt needs to be tightened with an impact wrench through the through-hole into the internal threaded section of the motor unit's mounting hole, the enlarged section prevents the bolt from tilting (being inserted at an angle). Therefore, there is no concern regarding bolt tightness when the motor unit is attached to the component.

[0010] Furthermore, the engine unit mounting structure for a vehicle according to a second aspect of the present invention is an engine unit mounting structure for a vehicle of the first aspect, wherein the length and inner diameter of the enlarged section are specified such that, when the bolt shank is inserted into the internal threaded section, the angle of inclination of the bolt shank with respect to an axial line of the mounting hole is 3 degrees or less.

[0011] According to the second aspect of the invention, the length and inner diameter of the enlarged section are determined such that the inclination angle of the bolt shank with respect to the axial line of the fastening hole, when the bolt shank is inserted into the internally threaded section, is 3 degrees or less. Thus, the inclination of the bolt (insertion at an angle) is further reduced compared to the case where the length and inner diameter of the enlarged section are determined such that its inclination angle is greater than 3 degrees.

[0012] As described above, according to the present invention, even if the rib projecting to a predetermined height is formed in the vicinity of the through-hole for inserting the bolt in the component formed in one piece by casting, there are no concerns regarding the tightening of the bolt when attaching the motor unit to the component. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The features and advantages as well as the technical and economic significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, showing: Fig. 1 a schematic perspective view showing an engine unit assembly structure according to one embodiment; Fig. 2 a schematic disassembled perspective view showing the motor unit assembly structure according to the embodiment; Fig. 3 a schematic side view showing the motor unit assembly structure according to the embodiment; Fig. 4 a schematic sectional view along line XX in Fig. 3; Fig. 5A a schematic sectional view showing a mounting hole according to the embodiment; and Fig. 5B is a schematic sectional view showing a state in which a bolt is inserted into the mounting hole according to the embodiment. DETAILED DESCRIPTION OF EXECUTION FORMS

[0014] An embodiment according to the present invention is described in detail below with reference to the drawings. It should be noted that, for the sake of simplicity, an arrow UP in the drawings indicates the upward direction of a vehicle, an arrow FR the forward direction of the vehicle, an arrow LH the left direction of the vehicle, and an arrow RH the right direction of the vehicle. When terms are used in the following description to describe the upward-downward, forward-backward, and right-left directions without specifying a particular direction, these refer to the upward-downward or vertical, forward-backward or longitudinal, and right-left or lateral directions of the vehicle. Furthermore, the right-left direction is synonymous with the vehicle's lateral direction.

[0015] A vehicle 12, such as a battery-powered electric vehicle or the like, equipped with a motor unit mounting structure 10 according to the present embodiment, has a component forming both sides of a front section and a component forming both sides of a rear section of a vehicle body. Here, the component forming both sides of the front section of the vehicle body (hereinafter referred to as the "front part 20 of the vehicle body") is described as shown in the Fig. 1 and Fig. Figure 2 is used as an example for the description. The front part 20 of the vehicle body is a cast item referred to as a "Gigacast component", in which several parts are integrally formed by die casting using a metal, for example an aluminum alloy or the like.

[0016] Both sides of the right and left side sections of the front part 20 of the vehicle body are integrally connected by a connecting wall 22, which generally has a rectangular and flat shape and is positioned in a central section in the direction of the vehicle's width. Wheel housings 28 with symmetrical shapes, each capable of accommodating the right and left wheels (front wheels, omitted in the illustration), are integrally formed on both sides of the right and left sides. A motor unit 14 for driving the right and left wheels (front wheels) is provided on an inner side in the direction of the vehicle's width of the front part 20 of the vehicle body (on a front face of the connecting wall 22).

[0017] The motor unit 14 has a housing 14A made of metal, for example an aluminum alloy or the like, and upright wall sections 24 are arranged integrally towards the front of the connecting wall 22 in the front part 20 of the vehicle body at both right and left ends. These upright wall sections face the housing 14A of the motor unit 14 in the vehicle width direction. Each of the upright wall sections 24 has a plurality of through holes 24A (e.g., two at the top and two at the bottom, for a total of four) through which (threaded) bolts or screws 18 are inserted to fasten the motor unit 14 to the front part 20 of the vehicle body, the vehicle width direction being its axial direction.

[0018] It should be noted that, as in Fig. Figure 5B shows that the screw 18 has an external thread section 18B of a predetermined length, which is formed only on a distal end section of a shaft 18A thereof, and that this external thread section 18B is designed to be screwed into (attached to) an internal thread section 16B of a fastening hole 16, which will be described later and is formed in the housing 14A of the motor unit 14.

[0019] Furthermore, as in the Fig. 1, Fig. 2, Fig. 3 to Fig. As shown in Figure 4, several ribs 26 are integrally formed on an outer surface of each of the upright wall sections 24 and also in the vicinity of each of the through-holes 24A, projecting outwards in the vehicle width direction up to a predetermined height. It should be noted that a plurality of ribs 27 are also integrally formed on an outer surface of each wheel arch 28, projecting outwards in the vehicle width direction up to a predetermined height. That is to say, several ribs 26 and 27 with a predetermined shape and a predetermined height are essentially integrally formed over the entire outer surfaces of the front part 20 of the vehicle body. This provides a configuration in which the front part 20 of the vehicle body is reinforced.

[0020] As in Fig. As shown in Figure 3, the ribs 26, which are integral to the outer surface of each of the upright wall sections 24, are configured to include a plurality of lateral ribs 26A extending longitudinally and a plurality of inclined ribs 26B extending in a direction inclined at an angle of approximately 45 degrees to the longitudinal direction, intersecting when viewed from the side in the vehicle width direction. Some of the lateral ribs 26A and the inclined ribs 26B are configured to surround and separate at least the upper and lower through-holes 24A on the rear side.

[0021] Accordingly, at least the upper and lower through-holes 24A on the rear are configured in such a way that they are not easily accessible to the worker by hand and cannot be reached. It should be noted that, as in Fig. Figure 4 shows the inclined ribs 26B having outer edges 26C in the longitudinal view, which are inclined such that the overhang height on the side of the lateral rib 26A is less than the overhang height above and below the lateral rib 26A.

[0022] As in the Fig. 2 and Fig. As shown in Figure 4, several (four) mounting holes 16, which are not through holes and each correspond to one of the through holes 24A in the front part 20 of the vehicle body, are formed on the rear end sections of both side walls of the housing 14A of the motor unit 14, with the vehicle width direction as their axial direction. Fig. As shown in Figure 5A, the internal threaded section 16B is formed on a downstream side in a fastening direction of the bolt / screw 18 in the fastening hole 16, and an enlarged section 16A of a predetermined length is formed on an upstream side in the fastening direction of the bolt / screw 18 in the fastening hole 16, the latter having an inner diameter that is larger than an outer diameter of the shank 18A of the bolt 18 without the external threaded section 18B (see Figure 5A). Fig. 5B).

[0023] Here are, as in Fig.As shown in Figure 5B, the length and inner diameter of the enlarged section 16A are designed such that the angle of inclination θ of the shank 18A of the bolt 18 with respect to an axial line C of the mounting hole 16, when the external threaded section 18B of the shank 18A of the bolt 18 is inserted into the internal threaded section 16B (before screwing begins), is 3 degrees or less. That is, the length and inner diameter of the enlarged section 16A are appropriately determined according to the length and outer diameter of the shank 18A (including the external threaded section 18B) of the bolt 18 to be screwed into the mounting hole 16.

[0024] Next, the operations of the motor unit assembly structure 10 according to the present embodiment, which is configured as above, will be described.

[0025] As described above, the front part 20 of the vehicle body, which is a component of the vehicle body, is formed in one piece by casting (die casting) a metal such as an aluminum alloy or the like, and the motor unit 14, which drives the wheels (front wheels), is provided on the inside of the front part 20 of the vehicle body in the vehicle width direction.

[0026] Here, the front part 20 of the vehicle body has upright wall sections 24 in the vehicle width direction, which face the housing 14A of the motor unit 14, and the upright wall sections 24 have through holes 24A formed therein, through which the shanks 18A of the bolts 18 for fastening the motor unit 14 to the front part 20 of the vehicle body are inserted. The ribs 26 are provided on the outer surface of the upright wall sections 24 in the vicinity of the through holes 24A and project outwards in the vehicle width direction to a predetermined height.

[0027] On the other hand, the housing 14A of the motor unit 14 has mounting holes 16, which correspond to the through holes 24A in the front part 20 of the vehicle body. The mounting holes 16 have internal threaded sections 16B on the downstream side in the mounting direction of the bolts 18, and enlarged sections 16A on the upstream side in the mounting direction of the bolts 18, with an inner diameter larger than the outer diameter of the shanks 18A of the bolts 18.

[0028] Accordingly, ribs 26 are formed in the vicinity of the through holes 24A for inserting the bolts into the front part 20 of the vehicle body. These ribs protrude to a predetermined height, in particular to such a height that it is difficult for the worker to reach the through holes 24A by hand, and even if the external threaded sections 18B of the shanks 18A of the bolts 18 have to be directly fastened to the internal threaded sections 16B of the fastening holes 16 through the through holes 24A with an impact wrench (not shown in the illustration) (the worker cannot screw by hand), the enlarged sections 16A prevent the shanks 18A (external threaded sections 18B) of the bolts 18 from tilting (being inserted at an angle to the axial line C of the fastening holes 16).

[0029] Accordingly, even if the motor unit 14 has an aluminum housing 14A, direct external tightening of the screws in the vehicle width direction using an impact wrench prevents damage to the internal thread sections 16B by the shanks 18A (external thread sections 18B) of the bolts / screws 18, and the external thread sections 18B of the bolts / screws 18 can be properly screwed into the internal thread sections 16B of the mounting holes 16. In other words, the problem of the external thread sections 18B of the bolts / screws 18 not being able to be screwed into the internal thread sections 16B of the mounting holes 16 can be suppressed, and concerns regarding the screw fastening when attaching the motor unit 14 to the front part 20 of the vehicle body can be avoided.

[0030] Furthermore, the length and inner diameter of the enlarged sections 16A are designed such that the inclination angle θ of the shanks 18A of the bolts / screws 18 with respect to the axial line C of the mounting holes 16 is 3 degrees or less when the shanks 18A (externally threaded sections 18B) of the bolts / screws 18 are inserted into the internally threaded sections 16B. Accordingly, the inclination of the shanks 18A (externally threaded sections 18B) of the bolts / screws 18 (inserted at an angle relative to the axial line C of the mounting holes 16) can be further reduced compared to the case where the length and inner diameter of the enlarged sections 16A are designed such that the inclination angle θ is greater than 3 degrees.

[0031] Since direct bolt fastening with an impact wrench can be achieved in this way without any concerns regarding the motor unit 14 with the aluminum housing 14A, the worker can omit the loose screwing in of the bolts 18 even if the ribs 26 are not formed on the outer surfaces of the upright wall sections 24 in the vicinity of the through holes 24A. This improves the efficiency of the assembly work of the motor unit 14 on the front part 20 of the vehicle body.

[0032] While the motor unit mounting structure 10 in the vehicle 12 according to the present embodiment has been described above with reference to the drawings, the motor unit mounting structure 10 according to the present embodiment is not limited to that shown in the drawings and can be modified in its design in a suitable manner without deviating from the idea and scope of the present invention. For example, in the case of a motor unit (not shown in the figure) for driving the right and left rear wheels, the motor unit is provided on the inside in the vehicle width direction of a component (rear part of the vehicle body, not shown in the figure) that forms both sides of the rear part of the vehicle body. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2021 - 127 097 A

[0002]

Claims

Engine unit assembly structure in a vehicle, wherein the engine unit assembly structure comprises: an integrally formed component by casting that forms both sides of a front part of a vehicle body or both sides of a rear part of the vehicle body;and a motor unit provided on an inside of the component in the vehicle width direction and driving wheels, the component comprising an upright wall section having a through-hole through which a bolt for fastening the motor unit passes and which faces the motor unit in the vehicle width direction, and a rib projecting to a predetermined height in a vicinity of the through-hole on an outer surface of the upright wall section in the direction of an outside in the vehicle width direction, and the motor unit having a fastening hole, the downstream side of which, in a bolt fastening direction, is an internally threaded section and the upstream side of which, in the bolt fastening direction, is an enlarged section whose inner diameter is larger than an outer diameter of a bolt shank, and which is open in accordance with the through-hole. Motor unit mounting structure according to claim 1, wherein the length and inner diameter of the enlarged section are specified such that, when the bolt shank is inserted into the internal threaded section, the angle of inclination of the bolt shank with respect to an axial line of the mounting hole is 3 degrees or less.

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