JP-7856946-B2 - Bush

Inventors

• 安武 嶺
• 秋竹 俊太郎
• 城 光
• 山本 佳祐
• 榎田 智幸
• 大森 幸一
• 具志堅 泰邦
• 田中 勇太

Assignees

• 三菱自動車工業株式会社

Dates

Publication Date

20260512

Application Date

20230323

Claims (4)

1. A bush comprising an inner cylinder, an outer cylinder, and an elastic member provided between them, A shape memory alloy is provided that is incorporated into the elastic member in a deformed state from a pre-stored shape , and by self-heating due to the application of electricity, it recovers its shape to the stored shape, thereby compressing or extending the elastic member between the inner cylinder or the outer cylinder, and changing the spring characteristics of the bush. A bush characterized by the following features.
2. The shape memory alloy is cylindrical, and its diameter expands or contracts during the shape recovery operation. The bush according to feature 1.
3. The shape memory alloy is provided coaxially with the inner cylinder and the outer cylinder. The bush according to feature 1.
4. Multiple cavities are provided in the elastic member at intervals in the circumferential direction, The shape memory alloy is provided in the cavity, A bush according to claim 1 or 2, characterized in that it is a bush.

Description

This invention relates to a bushing. As a vehicle suspension system, a system is known in which trailing arms or lower arms that support the wheels are pivotably connected to the vehicle body via bushings. A bushing comprises an inner cylinder, an outer cylinder, and an elastic member provided between them. For example, the inner cylinder is connected to a trailing arm or lower arm, and the outer cylinder is connected to the vehicle body. Such bushings are designed to have a predetermined spring characteristic (elastic modulus). Spring characteristics refer to the amount of change in deflection in response to a load. Incidentally, the greater the deflection of a bushing under load, or in other words, the lower the rigidity of the elastic component, the better the ride comfort tends to be, but the worse the handling stability tends to be. Furthermore, the less the bushing deflects under load, or in other words, the higher the rigidity of the elastic component, the better the handling stability, but the more the ride comfort tends to decrease. Thus, ride comfort and handling stability are often at odds. Therefore, Patent Document 1 discloses a technique for prioritizing either ride comfort or handling stability by changing the spring characteristics of a bush by supplying hydraulic pressure from a hydraulic source to a plurality of fluid chambers provided inside an elastic member. Japanese Patent Application Publication No. 10-138725 This is an explanatory diagram of a bush according to the first embodiment, where (A) is a plan view of the shape memory alloy before the shape recovery operation, (B) is a plan view of the shape memory alloy after the shape recovery operation, and (C) is a diagram showing the load-displacement characteristics of the bush.(A) is a cross-sectional view along the line X-X in Figure 1(A), and (B) is a modified example of the cross-sectional view along the line X-X in Figure 1(A).This is an explanatory diagram of a bush according to the second embodiment, where (A) is a plan view of the shape memory alloy before the shape recovery operation, (B) is a plan view of the shape memory alloy after the shape recovery operation, and (C) is a diagram showing the load-displacement characteristics of the bush.This is an explanatory diagram of a bush according to the third embodiment, where (A) is a plan view of the shape memory alloy before the shape recovery operation, (B) is a plan view of the shape memory alloy after the shape recovery operation, (C) is a cross-sectional view of (B) along line C-C, and (D) is a diagram showing the load-displacement characteristics of the bush.This is an explanatory diagram of a bush according to the fourth embodiment, where (A) is a plan view of the shape memory alloy before the shape recovery operation, (B) is a plan view of the shape memory alloy after the shape recovery operation, and (C) is a diagram showing the load-displacement characteristics of the bush.This is an explanatory diagram of a bush according to the fifth embodiment, where (A) is a plan view of the shape memory alloy before the shape recovery operation, and (B) is a plan view of the shape memory alloy after the shape recovery operation.This is an explanatory diagram of a bush according to the sixth embodiment, where (A) is a plan view of the shape memory alloy before the shape recovery operation, and (B) is a plan view of the shape memory alloy after the shape recovery operation. (First Embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment describes a case in which the bush of the present invention is applied to a vehicle suspension system that includes a bush that pivotably connects a lower arm supporting the vehicle's wheels to a suspension cross member (vehicle body). As shown in Figure 1(A), the bush 10A comprises a metal inner cylinder 12, an outer cylinder 14, and an elastic member 16 provided between them, the elastic member 16 being made of a shape memory alloy 18. The inner cylinder 12 and the outer cylinder 14 are cylindrical in shape, and an elastic member 16 is provided between the inner cylinder 12 and the outer cylinder 14. The inner cylinder 12, the outer cylinder 14, and the elastic member 16 are arranged coaxially, and various conventionally known elastic materials such as rubber can be used as the elastic member 16. The inner cylinder 12 is connected to a suspension cross member (not shown) via fastening members such as bolts and nuts, and the outer cylinder 14 is connected to a lower arm (not shown). The inner circumferential surface of the elastic member 16 is vulcanized and bonded to the outer circumferential surface of the inner cylinder 12, and the outer circumferential surface of the elastic member 16 is vulcanized and bonded to the inner circumferential surface of the outer cylinder 14. The shape memory alloy 18 performs a shape recovery operation by self-heating (Joule heating) due to the ap