Motor unit mounting structure in vehicles
The motor unit mounting structure addresses the challenge of attaching a motor unit to a vehicle's skeletal member with protruding ribs by using a skeletal member with through holes and ribs, and a motor unit with an expanded portion, ensuring secure and efficient bolt fastening without thread damage.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-29
- Publication Date
- 2026-06-10
AI Technical Summary
The challenge of attaching a motor unit to a vehicle's skeletal member, particularly when ribs protrude around through-holes, makes it difficult to fasten bolts due to interference and potential damage to female screw portions, especially when using an impact wrench.
The motor unit mounting structure includes a skeletal member with vertical wall portions featuring through holes and outward-protruding ribs, and a motor unit with a female threaded portion and an expanded portion to accommodate bolt insertion, ensuring the bolt is aligned correctly and preventing tilting during fastening.
This structure allows for secure and efficient attachment of the motor unit to the skeletal member without damaging the female threads, even with protruding ribs, by aligning the bolt correctly and preventing tilting, thus improving assembly efficiency.
Smart Images
Figure 2026095021000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a structure for mounting a motor unit in a vehicle.
Background Art
[0002] It has been conventionally known that a skeletal member constituting a vehicle body is integrally formed including the shapes of respective parts (see, for example, Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, a motor unit is provided in a vehicle such as an electric vehicle. The motor unit includes a metal case made of an aluminum alloy or the like. In order to attach the motor unit to a skeletal member of the vehicle body, a bolt is fastened (threaded) to a female screw portion formed in the case. Here, when the bolt is inserted obliquely into the female screw portion, in the case made of aluminum, the female screw portion is damaged by the bolt, and the bolt cannot be fastened (threaded). Therefore, first, an operator temporarily fastens the bolt by hand to the female screw portion, and then fastens the bolt to the female screw portion with an impact wrench.
[0005] On the other hand, there are body frame components called Gigacast, which are made by integrally forming multiple parts by casting them from a metal such as an aluminum alloy. These Gigacast components sometimes have multiple ribs that protrude to a predetermined height for reinforcement. Therefore, if these reinforcing ribs are formed around the through-holes for inserting bolts to fasten the motor unit to the Gigacast, it becomes difficult for a worker to reach the through-holes. In other words, it becomes difficult for a worker to temporarily fasten bolts to the female threaded portion of the motor unit through the through-holes.
[0006] If the bolt cannot be pre-tightened into the female thread by the worker and is instead directly fastened (screwed) into the female thread using an impact wrench, and the bolt is inserted into the female thread at an angle, the female thread may be damaged by the bolt, making it impossible to fasten (screw) the bolt. Thus, there are concerns about directly fastening bolts with an impact wrench when attaching the motor unit to the Gigacast.
[0007] Therefore, the present invention aims to provide a motor unit mounting structure for a vehicle in which, even if ribs protruding to a predetermined height are formed around through holes for bolt insertion in a skeletal member integrally formed by casting, there are no concerns regarding bolt fastening when attaching the motor unit to the skeletal member. [Means for solving the problem]
[0008] To achieve the above objective, the motor unit mounting structure in a vehicle according to the first embodiment of the present invention comprises a skeletal member integrally formed by casting and constituting the front side or rear side of the vehicle body, and a motor unit provided on the inside of the skeletal member in the vehicle width direction and driving the wheels, wherein the skeletal member has a vertical wall portion facing the motor unit in the vehicle width direction with through holes formed for inserting bolts for mounting the motor unit, and ribs projecting outward in the vehicle width direction to a predetermined height on the outer surface of the vertical wall portion and around the through holes, and the motor unit has a female threaded portion on the downstream side in the bolt fastening direction and an expanded portion with an inner diameter larger than the outer diameter of the bolt shaft on the upstream side in the bolt fastening direction and has a fastening hole formed corresponding to the through hole.
[0009] According to the first embodiment of the invention, skeletal members constituting the front or rear sides of the vehicle body are integrally molded by casting, and a motor unit for driving the wheels is provided on the inside of the skeletal member in the vehicle width direction. Here, the skeletal member has a vertical wall portion facing the motor unit in the vehicle width direction, and through holes for inserting bolts for attaching the motor unit are formed in the vertical wall portion. On the outer surface of the vertical wall portion and around the through holes, ribs are provided projecting outward in the vehicle width direction to a predetermined height. The motor unit also has fastening holes formed corresponding to the through holes of the skeletal member. The fastening hole has a female threaded portion on the downstream side in the bolt fastening direction, and an expanded portion with an inner diameter larger than the outer diameter of the bolt shaft on the upstream side in the bolt fastening direction.
[0010] Therefore, when bolts are fastened to the female threads of the motor unit's fastening holes through the through-holes in the integrally molded frame member by casting, ribs are formed that protrude to a predetermined height (to a height that makes it difficult for an operator's hand to reach the through-holes), and even when the only way to fasten the bolts to the female threads of the motor unit's fastening holes is through the through-holes using an impact wrench, the expanding portion prevents the bolts from tilting (being inserted at an angle). Thus, there are no concerns when fastening bolts when attaching the motor unit to the frame member.
[0011] Furthermore, the motor unit mounting structure in a vehicle according to a second embodiment of the present invention is the motor unit mounting structure in a vehicle according to the first embodiment, wherein the length and inner diameter of the expanding portion are formed such that the inclination angle of the shaft portion of the bolt with respect to the axis of the fastening hole when the shaft portion of the bolt is inserted into the female thread portion is 3 degrees or less.
[0012] According to the second embodiment of the invention, the length and inner diameter of the expansion portion are formed such that the angle of inclination of the bolt shaft with respect to the axis of the fastening hole when the bolt shaft is inserted into the female thread portion is 3 degrees or less. Therefore, compared to the case where the length and inner diameter of the expansion portion are formed so that the angle of inclination is greater than 3 degrees, the tilting of the bolt (insertion at an angle) is further suppressed. [Effects of the Invention]
[0013] As described above, according to the present invention, even if ribs protruding to a predetermined height are formed around the through holes for bolt insertion in a skeletal member integrally molded by casting, there is no concern regarding bolt fastening when attaching a motor unit to the skeletal member. [Brief explanation of the drawing]
[0014] [Figure 1] This is a schematic perspective view showing the motor unit mounting structure according to this embodiment. [Figure 2] This is a schematic exploded perspective view showing the motor unit mounting structure according to this embodiment. [Figure 3] This is a schematic side view showing the motor unit mounting structure according to this embodiment. [Figure 4] Figure 3 is a schematic cross-sectional view taken along the line XX. [Figure 5] (A) A schematic cross-sectional view showing the fastening hole according to this embodiment. (B) A schematic cross-sectional view showing the state in which a bolt is inserted into the fastening hole according to this embodiment. [Modes for carrying out the invention]
[0015] The embodiments of the present invention will be described in detail below with reference to the drawings. For the sake of explanation, in each figure, the arrow UP will indicate the upward direction of the vehicle, the arrow FR the forward direction of the vehicle, the arrow LH the left direction of the vehicle, and the arrow RH the right direction of the vehicle. In the following description, unless otherwise specified, the directions of up and down, front and back, and left and right will refer to the up and down, front and back, and left and right directions of the vehicle. The left and right direction is synonymous with the vehicle width direction.
[0016] The vehicle 12, such as an electric vehicle, equipped with the motor unit mounting structure 10 according to this embodiment, has skeletal members that constitute both the front and rear sides of the vehicle body. Here, as shown in Figures 1 and 2, the skeletal members that constitute both the front sides of the vehicle body (hereinafter referred to as "front vehicle body 20") will be used as an example for explanation. The front vehicle body 20 is a casting called a Gigacast, in which multiple parts are integrally formed by die-casting, for example, an aluminum alloy.
[0017] The front section 20 of the vehicle body is integrally connected on both sides by a roughly rectangular, flat connecting wall 22 located in the center in the width direction of the vehicle. On both sides of this wall, symmetrical wheelhouses 28 capable of housing the left and right wheels (front wheels: not shown) are integrally formed. A motor unit 14 for driving the left and right wheels (front wheels) is provided on the inside of the front section 20 in the width direction of the vehicle body (in front of the connecting wall 22).
[0018] The motor unit 14 is equipped with a metal case 14A made of aluminum alloy or the like. At both the left and right ends of the connecting wall 22 at the front of the vehicle body 20, vertical wall portions 24 are integrally connected to the case 14A of the motor unit 14 in the vehicle width direction, extending forward. Each vertical wall portion 24 has multiple through holes 24A formed in the vehicle width direction axially (for example, two vertically and two vertically, for a total of four) through which bolts 18 for attaching the motor unit 14 to the front of the vehicle body 20 are inserted.
[0019] As shown in FIG. 5(B), the bolt 18 has a male screw portion 18B of a predetermined length formed only at the tip of its shaft portion 18A, and the male screw portion 18B is screwed (fastened) into a female screw portion 16B of a fastening hole 16, which will be described later, formed in the case 14A of the motor unit 14.
[0020] Further, as shown in FIGS. 1 to 4, on the outer surface of each vertical wall portion 24 and around each through hole 24A, a plurality of ribs 26 protruding outward in the vehicle width direction to a predetermined height are integrally formed. A plurality of ribs 27 protruding outward in the vehicle width direction to a predetermined height are also integrally formed on the outer surface of each wheel house 28. That is, a plurality of ribs 26 and 27 having a predetermined shape and protruding height are integrally formed on substantially the entire outer surface of the front portion 20 of the vehicle body. Thereby, the front portion 20 of the vehicle body is configured to be reinforced.
[0021] As shown in FIG. 3, the rib 26 integrally formed on the outer surface of each vertical wall portion 24 is configured such that, in a side view seen from the vehicle width direction, a plurality of horizontal ribs 26A along the front-rear direction and a plurality of inclined ribs 26B along a direction inclined at an angle of approximately 45 degrees with respect to the front-rear direction intersect with each other. And a part of the horizontal ribs 26A and the inclined ribs 26B are configured to surround at least the upper and lower through holes 24A at the rear side so as to partition them.
[0022] Therefore, it is configured such that it is difficult for an operator's hand to reach at least the upper and lower through holes 24A at the rear side. As shown in FIG. 4, when viewed from the front-rear direction, the outer edge end portion of the inclined rib 26B is formed obliquely such that the protruding height on the horizontal rib 26A side is lower than the protruding heights on the upper and lower sides of the horizontal rib 26A.
[0023] As shown in Figures 2 and 4, at the rear ends of both side walls of the motor unit 14 case 14A, a plurality (4) of non-penetrating fastening holes 16 are formed, each corresponding to the through-holes 24A of the front of the vehicle body 20, with the vehicle width direction as the axial direction. As shown in Figure 5(A), a female threaded portion 16B is formed on the downstream side of the fastening direction of the bolt 18 in the fastening hole 16, and an expanded portion 16A is formed for a predetermined length on the upstream side of the fastening direction of the bolt 18, with an inner diameter larger than the outer diameter of the shaft portion 18A (see Figure 5(B)) of the bolt 18 excluding the male threaded portion 18B.
[0024] Here, as shown in Figure 5(B), the length and inner diameter of the expanding portion 16A are formed so that the inclination angle θ of the shaft portion 18A of the bolt 18 with respect to the axis line C of the fastening hole 16 when the male threaded portion 18B of the shaft portion 18A of the bolt 18 is inserted into the female threaded portion 16B (before screwing begins) is 3 degrees or less. In other words, the length and inner diameter of the expanding portion 16A are set appropriately according to the length and outer diameter of the shaft portion 18A (including the male threaded portion 18B) of the bolt 18 to be fastened into the fastening hole 16.
[0025] The operation of the motor unit mounting structure 10 according to this embodiment, which has the configuration described above, will now be explained.
[0026] As described above, the front part 20 of the vehicle body, which is a structural member of the vehicle body, is integrally molded by die-casting of a metal such as an aluminum alloy, and a motor unit 14 for driving the wheels (front wheels) is provided on the inside of the front part 20 in the width direction of the vehicle body.
[0027] Here, the front part 20 of the vehicle body has a vertical wall portion 24 that faces the case 14A of the motor unit 14 in the vehicle width direction, and a through hole 24A is formed in the vertical wall portion 24 through which the shaft portion 18A of a bolt 18 for attaching the motor unit 14 to the front part 20 of the vehicle body is inserted. On the outer surface of the vertical wall portion 24 and around the through hole 24A, a plurality of ribs 26 are provided projecting outward in the vehicle width direction to a predetermined height.
[0028] On the other hand, the case 14A of the motor unit 14 has a fastening hole 16 formed in correspondence with the through hole 24A of the front part 20 of the vehicle body. The fastening hole 16 has a female threaded portion 16B on the downstream side in the fastening direction of the bolt 18, and an expanded portion 16A on the upstream side in the fastening direction of the bolt 18, with an inner diameter larger than the outer diameter of the shaft portion 18A of the bolt 18.
[0029] Therefore, multiple ribs 26 are formed around the through-hole 24A for bolt insertion in the front part 20 of the vehicle body, protruding to a predetermined height, specifically to a height that makes it difficult for an operator's hand to reach the through-hole 24A and prevents the operator from reaching the through-hole 24A. Even when the only way to fasten the male threaded portion 18B of the shaft portion 18A of the bolt 18 to the female threaded portion 16B of the fastening hole 16 is through the through-hole 24A using an impact wrench (not shown) (where the operator cannot temporarily fasten it by hand), the expanding portion 16A can suppress the tilting of the shaft portion 18A (male threaded portion 18B) of the bolt 18 (being inserted at an angle to the axis line C of the fastening hole 16).
[0030] Therefore, even with a motor unit 14 equipped with an aluminum case 14A, when bolting directly from the outside in the vehicle width direction using an impact wrench, damage to the female thread portion 16B by the shaft portion 18A (male thread portion 18B) of the bolt 18 can be prevented, and the male thread portion 18B of the bolt 18 can be properly screwed into the female thread portion 16B of the fastening hole 16. In other words, the occurrence of a problem in which the male thread portion 18B of the bolt 18 cannot be screwed into the female thread portion 16B of the fastening hole 16 can be prevented, and concerns can be avoided when bolting the motor unit 14 to the front part 20 of the vehicle body.
[0031] Furthermore, the length and inner diameter of the expanding portion 16A are formed such that the inclination angle θ of the shaft portion 18A (male threaded portion 18B) of the bolt 18 with respect to the axis C of the fastening hole 16 when the shaft portion 18A (male threaded portion 18B) of the bolt 18 is inserted into the female threaded portion 16B is 3 degrees or less. Therefore, compared to the case where the length and inner diameter of the expanding portion 16A are formed such that the inclination angle θ is greater than 3 degrees, the inclination of the shaft portion 18A (male threaded portion 18B) of the bolt 18 (being inserted at an angle with respect to the axis C of the fastening hole 16) can be suppressed even more effectively.
[0032] Furthermore, since direct bolt fastening with an impact wrench can be performed on the motor unit 14 equipped with an aluminum case 14A without any concerns, the temporary tightening of the bolts 18 by the worker can be omitted even if multiple ribs 26 are not formed on the outer surface of the vertical wall portion 24 and around the through hole 24A. Therefore, the efficiency of the assembly work of the motor unit 14 to the front portion 20 of the vehicle body can be improved.
[0033] The motor unit mounting structure 10 in the vehicle 12 according to this embodiment has been described above based on the drawings. However, the motor unit mounting structure 10 according to this embodiment is not limited to the illustrated structure, and can be modified as appropriate without departing from the spirit of the present invention. For example, in the case of a motor unit (not shown) for driving the left and right rear wheels, the motor unit is provided on the inside in the vehicle width direction of the skeletal members (rear of the vehicle body: not shown) that constitute both sides of the rear of the vehicle body. [Explanation of symbols]
[0034] 10. Motor unit mounting structure 14 Motor Unit 16 fastening holes 16A Expansion section 16B Female thread section 18 volts 20 Front of the vehicle body (framework) 24 Vertical wall section 24A through hole 26 Ribs
Claims
1. A skeletal member formed integrally by casting, which constitutes the front side or rear side of the vehicle body, A motor unit for driving the wheels is provided on the inner side of the frame member in the vehicle width direction, Equipped with, The aforementioned skeletal member is Through holes for inserting bolts for mounting the motor unit are formed in the vertical wall portion facing the motor unit in the vehicle width direction, On the outer surface of the aforementioned vertical wall portion, a rib is provided projecting outward in the vehicle width direction to a predetermined height around the through hole, It has, The motor unit is A motor unit mounting structure in a vehicle having a fastening hole formed corresponding to the through hole, wherein the downstream side in the bolt fastening direction is a female threaded portion, and the upstream side in the bolt fastening direction is an enlarged portion with an inner diameter larger than the outer diameter of the bolt shaft.
2. The length and inner diameter of the expanded portion are formed such that the angle of inclination of the bolt shaft with respect to the axis of the fastening hole when the bolt shaft is inserted into the female thread portion is 3 degrees or less.