Power transmission unit for vehicles

Abstract

To provide a power transmission unit for vehicles that minimizes vibration transmission sensibility by inhibiting formation of a torque tube flexure.SOLUTION: An engine-side bearing support member 72 that supports an engine-side bearing 60 is integrally coupled to a coupling part 54 of an engine 20, and a transmission-side bearing support member 74 that supports a transmission-side bearing 66 is integrally coupled to a coupling part 56 of a transmission 30. Accordingly, a constraint force derived from rotation unbalance or misalignment of a shaft 50 is not directly transmitted to a torque tube 52 via the engine-side bearing 60 and transmission-side bearing 66, but is transmitted to the coupling part 54 of the engine 20 and the coupling part 56 of the transmission 30. This results in a power transmission unit 40 for vehicles characterized in that formation of a torque tube flexure is inhibited and a vibration transmission sensibility is minimized.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a power transmission device for a vehicle that suppresses vibrations. [Background technology]

[0002] Front-engine, rear-drive vehicles (FR vehicles) are well known, in which an engine is mounted at the front of the vehicle and a transmission is mounted at the rear of the vehicle, and the vehicle runs on rear-wheel drive. In such FR vehicles, the engine and transmission are connected by a power transmission device composed of a propeller shaft (hereinafter referred to as the shaft) and a torque tube. The shaft connects the engine and transmission along the longitudinal direction of the vehicle, and transmits power by rotating about an axis along the longitudinal direction. The torque tube is a cylindrical cover for the shaft to be inserted rotatably, and connects the engine and transmission to form a single rigid body.

[0003] In a torque tube, gear noise caused by meshing of gears constituting a connected engine or transmission, vibrations from a shaft rotating at high speed, and other factors are transmitted to and resonate with the torque tube, generating vibrations, and so suppression of these vibrations is required. One example is a power transmission device for vehicles described in Patent Document 1. Patent Document 1 discloses the shape and structure of a vibration suppressing member contained within the torque tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-280053 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to suppress vibration of the torque tube, it is effective to prevent the torque tube from being bent (hereinafter referred to as torque tube bending). The torque tube is easily bent due to a forcing force generated by rotational imbalance or misalignment of the shaft, which results in an increase (deterioration) in the level of vibration generated in the vehicle cabin, i.e., the vibration transmission sensitivity.

[0006] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a power transmission device for a vehicle that reduces vibration transmission sensitivity by suppressing the formation of torque tube bends. [Means for solving the problem]

[0007] The gist of a first invention is a power transmission device for a vehicle comprising: (a) a shaft that connects an engine and a transmission mounted on a vehicle along the longitudinal direction of the vehicle and rotates about an axis along the longitudinal direction to transmit driving force from the engine; a torque tube formed in a cylindrical shape through which the shaft is rotatably inserted, connecting the engine and the transmission such that the engine and the transmission form a single rigid body; an engine-side bearing that supports the shaft on the engine side; and a transmission-side bearing that supports the shaft on the transmission side, wherein: (b) an engine-side bearing support member that supports the engine-side bearing is integrally connected to the engine; and (c) a transmission-side bearing support member that supports the transmission-side bearing is integrally connected to the transmission. Effect of the Invention

[0008] According to the first aspect of the present invention, the engine-side bearing support member that supports the engine-side bearing is integrally connected to the engine, and the transmission-side bearing support member that supports the transmission-side bearing is integrally connected to the transmission. As a result, a compulsive force generated by a rotational imbalance or misalignment of the shaft is transmitted to the connection part with the engine and the connection part with the transmission via the engine-side bearing and the transmission-side bearing, rather than being transmitted directly to the torque tube. Therefore, it is possible to provide the vehicle power transmission device in which the formation of torque tube bends is suppressed and vibration transmission sensitivity is reduced. [Brief description of the drawings]

[0009] [Figure 1] 1A and 1B are schematic diagrams illustrating a conventional example of the general configuration of a power transmission device for a vehicle, in which (a) is a side view, and (b) is a diagram illustrating the formation of a bent torque tube. [Diagram 2] 1A and 1B are schematic diagrams illustrating an example of a schematic configuration of a vehicle power transmission device to which the present invention is applied, in which (a) is a side view and (b) is a diagram illustrating the formation of a bent torque tube. [Diagram 3] 5 is a diagram illustrating a comparison of vibration transmission sensitivity of a vehicle power transmission device to which the present invention is applied with a conventional example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0011] Fig. 1 is a schematic diagram illustrating a conventional example of the general configuration of a power transmission device 40. Fig. 1(a) is a schematic diagram of the power transmission device 40 and its vicinity as viewed from the side of a vehicle 10. An engine 20 and a clutch 22 connected to the engine 20 are mounted on the front portion (left side of the drawing) of the vehicle 10, and a transmission 30 is mounted on the rear portion (right side of the drawing) of the vehicle 10. The engine 20 (including the clutch 22) and the transmission 30 are connected by the power transmission device 40 having a shaft 50 and a torque tube 52.

[0012] The shaft 50 is connected to the transmission 30 along the longitudinal direction of the vehicle 10 from the engine 20 via the clutch 22. The driving force of the engine 20 is transmitted to the transmission 30 by the shaft 50 rotating about an axis along the longitudinal direction.

[0013] The torque tube 52 is formed in a cylindrical shape so as to cover the outer periphery of the shaft 50 so that the shaft 50 can be rotatably inserted therethrough, and integrally includes a tapered first cylindrical portion 52a connected to the engine 20, a tapered second cylindrical portion 52b connected to the transmission 30, and a third cylindrical portion 52c having a relatively smaller diameter than the first cylindrical portion 52a and the second cylindrical portion 52b and connecting the first cylindrical portion 52a and the second cylindrical portion 52b in the longitudinal direction of the vehicle 10. The first cylindrical portion 52a of the torque tube 52 is integrally connected to a connecting portion 54 of the engine 20 by a fastener such as a bolt. Similarly, the second cylindrical portion 52b of the torque tube 52 is integrally connected to a connecting portion 56 of the transmission 30 by a fastener such as a bolt. In other words, the engine 20 to the transmission 30 via the torque tube 52 are integrally connected as one rigid body.

[0014] The shaft 50 is rotatably supported by an engine-side bearing 60 on the engine 20 side (left side of the drawing) and a transmission-side bearing 66 on the transmission 30 side (right side of the drawing). The engine-side bearing 60 is supported by an engine-side bearing support member 62, which is fixed to a first fixed portion 64 in the first cylindrical portion 52a of the torque tube 52 and supported non-rotatably. Similarly, the transmission-side bearing 66 is supported by a transmission-side bearing support member 68, which is fixed to a second fixed portion 70 in the second cylindrical portion 52b of the torque tube 52 and supported non-rotatably. The engine-side bearing support member 62 (including the first fixed portion) and the transmission-side bearing support member 68 (including the second fixed portion) are arranged so that the distance between the engine-side bearing 60 and the transmission-side bearing 66 is the bearing distance Lb. The bearing distance Lb is a set distance that is predetermined by design based on the resonance conditions of the shaft 50 and cannot be changed.

[0015] FIG. 1B is a schematic diagram of a side view of a vehicle 10, illustrating an example in which the torque tube in the conventional example in FIG. 1A is bent by a forced force. The forced force generated by the rotational imbalance or misalignment of the shaft 50 during running is transmitted to a first fixed portion 64 in the first cylindrical portion 52a via an engine-side bearing 60 and an engine-side bearing support member 62. For example, the forced force is transmitted in the direction indicated by the arrow on the left side of FIG. 1B (vertically upward). Similarly, on the transmission 30 side, the forced force is transmitted to a second fixed portion 70 in the second cylindrical portion 52b via a transmission-side bearing 66 and a transmission-side bearing support member 68 in the direction indicated by the arrow on the right side of FIG. 1B (vertically upward). Since the transmission points of the forcing force (the first fixed portion 64 and the second fixed portion 70) are located near the third cylindrical portion 52c, the forcing force is easily transmitted to the third cylindrical portion 52c, which has a relatively small diameter, and a torque tube bend is formed in the upward direction of the page centered on the third cylindrical portion 52c. In FIG. 1B, a bending displacement of ΔU1 is shown at the center of the third cylindrical portion 52c. For example, if the transmission points of the forcing force (the first fixed portion 64 and the second fixed portion 70) are moved in a direction away from the third cylindrical portion 52c, the forcing force is less likely to be transmitted to the third cylindrical portion 52c, which is considered to tend to suppress the formation of the torque tube bend. However, in the conventional example, the distance between the engine side bearing 60 and the transmission side bearing 66 is determined by the resonance condition of the shaft 50 at the bearing distance Lb, and the bearings and their support positions cannot be changed, so there was a problem in suppressing the formation of the torque tube bend.

[0016] In contrast to the conventional example in Fig. 1, Fig. 2 is a diagram for explaining an example of the schematic configuration of a power transmission device 40 to which the present invention is applied. Parts common to those in Fig. 1 are given the same reference numerals and explanations thereof will be omitted.

[0017] FIG. 2(a) is a schematic diagram of the vicinity of the power transmission device 40 as viewed from the side of the vehicle 10, similar to FIG. 1(a). In FIG. 2(a), the engine-side bearing support member 72 is not fixed to the first cylindrical portion 52a of the torque tube 52, but is integrally connected to the connecting portion 54 of the engine 20 together with the first cylindrical portion 52a of the torque tube 52 by a fastener such as a bolt. Similarly, the transmission-side bearing support member 74 is not fixed to the second cylindrical portion 52b of the torque tube 52, but is integrally connected to the connecting portion 56 of the transmission 30 together with the second cylindrical portion 52b of the torque tube 52 by a fastener such as a bolt. The engine-side bearing support member 72 and the transmission-side bearing support member 74 are provided to protrude close to each other from the connecting portion 54 of the engine 20 and the connecting portion 56 of the transmission 30 so that the distance between the engine-side bearing 60 and the transmission-side bearing 66 satisfies the prescribed bearing distance Lb.

[0018] FIG. 2(b) is a schematic diagram illustrating an example in which the torque tube in this embodiment (FIG. 2(a)) is bent by a forcing force, in comparison with a conventional example (FIG. 1(a)). A forcing force generated by a rotational imbalance or misalignment of the shaft 50 during running is transmitted to the connecting part 54 of the engine 20 via the engine-side bearing 60 and the engine-side bearing support member 72, rather than to the torque tube 52. For example, the force is transmitted in the direction of the arrow on the left side of FIG. 2(b) (vertically upward). Similarly, on the transmission 30 side, the force is transmitted in the direction of the arrow on the right side of FIG. 2(b) (vertically upward) to the connecting part 56 of the transmission 30 via the transmission-side bearing 66 and the transmission-side bearing support member 74. Because the points at which the forcing force is transmitted (connecting portions 54 and 56) are located at both ends of the torque tube 52, the forcing force is less likely to be transmitted to the third cylindrical portion 52c, which has a relatively small diameter, and therefore the torque tube is less likely to bend upward in the page. The bending deformation of the central portion of the third cylindrical portion 52c is suppressed to ΔU2 (ΔU2<ΔU1), which is smaller than that of the conventional example (FIG. 1(b)).

[0019] Fig. 3 is a diagram comparing the vibration generation level in the vehicle cabin, i.e., the vibration transmission sensitivity, between the power transmission device 40 of the conventional example (Fig. 1) and the power transmission device 40 of this embodiment (Fig. 2). Fig. 3(a) compares the vibration transmission sensitivity on the engine side (front section), and Fig. 3(b) compares the vibration transmission sensitivity on the transmission side (rear section), with the horizontal axis of each diagram indicating the vibration frequency. In both Fig. 3(a) and (b), the vibration transmission sensitivity of this embodiment is reduced (improved) compared to the conventional example.

[0020] As described above, according to this embodiment, the engine-side bearing support member 72 that supports the engine-side bearing 60 is integrally connected to the connecting portion 54 of the engine 20, and the transmission-side bearing support member 74 that supports the transmission-side bearing 66 is integrally connected to the connecting portion 56 of the transmission 30. As a result, a compelling force generated due to rotational imbalance or misalignment of the shaft 50 is not transmitted directly to the torque tube 52, but is transmitted to the connecting portion 54 with the engine 20 and the connecting portion 56 with the transmission 30 via the engine-side bearing 60 and the transmission-side bearing 66. Therefore, it is possible to provide a vehicle power transmission device 40 that suppresses the formation of torque tube bends and reduces vibration transmission sensitivity.

[0021] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0022] For example, in the above-described embodiment, the vehicle 10 is engine-driven, but the present invention is not limited to this. For example, the present invention can be applied to a hybrid electric vehicle equipped with an engine and an electric motor as a power source.

[0023] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0024] 10: vehicle 20: engine 30: transmission 40: power transmission device (power transmission device for vehicle) 50: shaft 52: torque tube 60: engine side bearing 66: transmission side bearing 72: engine side bearing support member 74: transmission side bearing support member

Claims

[Claim 1] A power transmission device for a vehicle, comprising: a shaft that connects an engine and a transmission mounted on a vehicle along a longitudinal direction of the vehicle and rotates about an axis along the longitudinal direction to transmit a driving force from the engine; a torque tube that is formed in a cylindrical shape through which the shaft is rotatably inserted and connects the engine and the transmission such that the engine and the transmission form a single rigid body; an engine-side bearing that supports the shaft on the engine side; and a transmission-side bearing that supports the shaft on the transmission side, an engine-side bearing support member for supporting the engine-side bearing is integrally connected to the engine; a transmission-side bearing support member for supporting the transmission-side bearing, the transmission-side bearing support member being integrally connected to the transmission;

Images