JPH04365628A - Power unit structure for vehicle - Google Patents

Abstract

PURPOSE:To suppress noise and vibration of a vehicle by effectively preventing a winding-up phenomenon due to the driving reactive force generated by a differential gear device. CONSTITUTION:A connecting member 10 extends in nearly parallel to a propeller shaft 5, and the front edge is connected with the rear edge of a differential gear case 9, and the rear edge is connected with the transverse case part 4b of a transfer case 4. A mounting device 14 which supports the rear edge part of a power unit is installed at a bendable part between the longitudinal case part 4 and the transverse case part 4b. Accordingly, the stress due to the winding-up which acts on the bendable part is received also by the mounting device 14. Accordingly, because of the existence of the mounting device 14, the reinforcing effect can be obtained for the acting force for the relative shift, such as the force for separating the longitudinal case part 4a of the transfer case 4 and the transverse case part 4b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power unit structure having an engine, a transmission device, a transfer device, and a differential device, and more particularly to a support structure thereof.

0002

2. Description of the Related Art An example of a power unit structure that takes measures against vehicle vibration and noise is disclosed in Japanese Patent Laid-Open No. 62-261529. In this disclosed structure, the differential device is integrally connected to the engine disposed above the differential device using a bracket, thereby reducing the vibration of the vehicle body.
Trying to reduce noise.

0003

[Problem to be Solved] A driving reaction force from the driving wheels is an acting force transmitted to a differential device that distributes driving force to the driving wheels via the rotating shaft of the driving wheels. This drive reaction force causes a so-called wind-up in the differential device, which causes displacement around the rotation axis of the drive wheels, which causes a problem in that vibration and noise of the vehicle increase. Further, when windup occurs, a loss of drive torque also occurs.

[0004] In the configuration disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-261529, it is difficult to effectively reduce windup in a configuration in which the differential device is disposed on the side of the engine. In addition, since the bracket connects the engine and differential device vertically, it is effective in preventing relative displacement between the two, but the support point between the rotating shaft, which is the input point of the drive reaction force, and the bracket is Because they are close to each other, it is not effective in reducing vibration and noise caused by windup.

[0005] FR as a means of reducing windup
In terms of layout, a structure in which a transmission case and a differential device are connected by a connecting member is disclosed in Japanese Patent Application Laid-Open No. 63-269721. If this configuration is simply applied to the one disclosed in JP-A-62-261529, a force is generated at a position (transfer case) that is offset from the engine output shaft due to windup, and the engine, transmission, and transfer force Torsional torque is generated in the power plant section. This adversely affects the joints of the engine, transmission, and transfer, and also causes twisting in the cylinder block, deforming the cylinder bore.

Therefore, an object of the present invention is to provide a power unit structure that can effectively prevent the windup phenomenon based on the drive reaction force generated in the power unit, particularly the differential device, and reduce vehicle noise and vibration. be. Furthermore, it is an object of the present invention to connect the transfer case and the differential device with a connecting member in order to arrange a power unit mounting device at a bent portion of a transfer case, which is a component of the power unit, and to reduce vibration noise caused by windup. The purpose is to alleviate the concentration of acting force on the bending portion of the transfer case, which occurs in such cases.

Furthermore, it is possible to suppress the vibration and noise of the power unit due to wind-up of the differential device based on drive reaction force while minimizing the burden on the components of the power unit.

[0008]

[Means for Solving the Problems] The present invention for solving the above problems is constructed as follows. The vehicle power unit structure of the present invention includes an engine arranged so that its output shaft extends along the longitudinal direction of the vehicle, a transmission device arranged coaxially with the output shaft of the engine, and a transmission device arranged on the output side of the transmission. a transfer device that transmits power in the lateral direction of the vehicle; a propeller shaft that is connected to the output side of the transfer device and extends parallel to the output shaft of the engine; a case member that covers the transfer device and the transmission device and has a vertical case portion extending in the longitudinal direction of the vehicle, and a horizontal case portion extending from the vertical case portion in the lateral direction of the vehicle; , a mount member for a transmission device attached to a bent portion formed by a vertical case portion and a horizontal case portion of the case member, and a connecting member extending substantially parallel to the propeller shaft and connecting the differential device and the case member. It is characterized by:

The present invention is suitable for a power unit structure in which an engine and a differential device are arranged side by side in the horizontal direction.

0010

[Operation] A rotational reaction force acts on the differential device from the left and right drive wheels in a direction opposite to the direction of rotation thereof. In the configuration of this example, the differential device and the case member are connected by a connecting member extending substantially parallel to the propeller shaft, and the connecting portion on the other end side of the connecting member is the input point of the driving reaction force of the differential device, that is, Since it is far away from the rotation axis of the drive wheel, it is effective in preventing windup. In this case, an acting force based on a driving reaction force transmitted from the differential device via the connecting member acts on the case member that is the connecting portion on the other end side of the connecting member. As a result, a torsion moment acts on the vertical case portion of the case member via the horizontal case portion to which the connecting member is coupled. Due to this torsional moment, a force that tends to separate the vertical case part and the horizontal case part concentrates on the bent part that is the joint between the vertical case part and the horizontal case part. In the present invention, the mount member of the transmission device is attached to this bent portion, and the power unit is supported via this portion. This mounting member not only has the function of supporting the transmission device, but also has the function of relieving the stress caused by the moment acting on the bent portion of the case member via the connecting member to prevent wind-up of the differential device. Combined with motsu.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. Referring to FIGS. 1, 2 and 3, a power unit structure of a front wheel drive vehicle to which the present invention is applied is schematically shown. The power unit 1 includes a vertical engine 2 disposed to extend in the longitudinal direction of the vehicle, a transmission case 3 housing a transmission device (not shown) connected to the rear end or output end of the engine 2, and A transfer case 4 that is connected to the rear end of the transmission device 3 and accommodates a transfer device (not shown) that extends in the lateral direction of the vehicle; and a transfer case 4 that is connected to the output end of the transfer device and that is connected to the engine 2 and the rotation axis L1 of the transmission device. It houses a propeller shaft 5 that extends forward in substantially parallel fashion, and a differential device (not shown) that is connected to the output end of the propeller shaft 5 and distributes driving force to axles 7 and 8 for left and right front wheels FL and FR. A differential case 9 is provided. The rotation axis L2 of the axles 7 and 8 and the axis of the differential device are coaxially arranged.

Note that a cooling fan 6 is attached to the front side of the engine 2. In the arrangement of this example, the engine 2 and the differential device are located side by side in the lateral direction. The transfer case 4 includes a vertical case portion 4a connected to the rear end of the transmission case 3 and extending in the longitudinal direction of the vehicle body, and a horizontal case portion 4b extending laterally from the vertical case portion. Differential case 9 and transfer case 4 are connected by a connecting member 10. The connecting member 10 extends substantially parallel to the propeller shaft 5, and its front end is attached to the rear end of the differential case 9 with a bolt 11, and its rear end is connected to the horizontal case portion 4b of the transfer case 4 with a bolt 12.

The engine 2 and the differential device are supported on a rectangular support 13. Further, a pair of mission mount devices 14 are attached to both sides of the vertical case portion 4a of the transfer case 4, and support the rear end of the power unit consisting of the engine 2, transmission device, transfer device, propeller shaft 5, and differential device. It looks like this. Furthermore, a pair of engine mount devices 15 are attached to both sides of the engine.

As shown in FIG. 4, the transfer case 4
The mission mount device 14 attached to the vehicle has a U-shaped bracket 16 and a rubber bushing 17. The bracket 16 includes a web portion 16a attached to the vertical case portion 4a, and a pair of flange portions 16b extending in parallel from both ends of the web portion 16a in the longitudinal direction of the vehicle body.
, 16c. In this case, as shown in FIG. 4, the rear flange portion 16c has through holes 18 and 19, through which bolts (not shown) are inserted and fixed to the horizontal case portion 4b.

The engine mount device 14 includes a U-shaped bracket 20 provided above and below and having flange portions extending in the horizontal direction, and a rubber bushing 21 supported by the bracket 20. As shown in FIG. 3, the mounting devices 14 and 15 are arranged on the rotation axis L1 of the engine, that is, the power transmission axis of the power unit in the vertical direction. When viewed from above, the positions supported by the mount devices 14 and 15 are symmetrical with respect to the rotation axis L1. Thereby, the power unit can suppress rotational movement, that is, roll, about the engine rotation axis as much as possible.

In the above structure, when a driving force acts on the front wheels FL and FR axles 7 and 8, a driving reaction force from the road surface acts in the opposite direction to the driving force. The moment due to this drive reaction force acts to cause rotational displacement, or windup, around the axles 7 and 8 of the differential device. However, in this example structure,
Since the differential case 9 is connected to the transfer case 4 via the connecting member 10, this windup can be suppressed.

Since the other end of the connecting member 10 supporting the differential case 9 is supported by the transfer case 4 remote from the rotation axis L2, which is the input point of the driving reaction force moment, the supporting effect against the moment is high. In this case, since the rear end of the connecting member 10 is connected to the lateral case portion 4b of the transfer case 4 at a position laterally away from the engine rotation axis L1, the transfer case 4 is not affected by the wind-up operation from the differential device. The force based on this will act as a torsional moment. In particular, the vertical case part 4a and the horizontal case part 4
The continuous portion with b, that is, the bent portion becomes a point of application of the torsional moment due to the wind-up, so stress becomes large. In this example, a mount device 14 that supports the rear end of the power unit is attached to this bent portion. Therefore, the mount device 14 also takes on the stress due to the windup that acts on the bent portion. In particular, the presence of the mounting device 14 provides a reinforcing effect against forces that tend to cause relative displacement, such as forces that tend to separate the vertical case portion 4a and horizontal case portion 4b of the transfer case 4.

[0018]

[Effect] According to the present invention, the mounting device of the power unit is arranged at the bent part of the transfer case, which is a component of the power unit, so that the connection member connects the transfer case and the differential device in order to reduce vibration noise caused by windup. It is possible to alleviate the concentration of acting force on the bent portion of the transfer case that occurs when the transfer case is connected. Therefore, while reducing the load on the components of the power unit as much as possible, it is possible to suppress vibrations and noise of the power unit due to wind-up of the differential device based on drive reaction force. Since the mount device is disposed on the power transmission shaft of the power unit structure when viewed in the horizontal direction, it is possible to enhance the roll suppression effect of the power unit. This can further enhance the damping effect.

Furthermore, by constructing the mount member with a bracket and a rubber bushing, the reinforcing effect can be enhanced, and the rigidity of the bending portion of the transfer device can be increased.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the structure of a power unit according to an embodiment of the present invention;

FIG. 2 is a schematic plan view of the structure of the power unit of the embodiment shown in FIG. 1;

FIG. 3 is a side view of the power unit structure according to the embodiment of FIG. 1;

FIG. 4 is a perspective view showing the structure of the bending portion of the present invention.

[Explanation of symbols]

1 Power unit 2 Engine 3 Transmission case 4 Transfer case 5 Propeller shaft 9 Differential case 10 Connecting member 14 Mounting device 15 Mounting device

Claims (2)

[Claims] Claims: 1. An engine disposed such that its output shaft extends along the longitudinal direction of a vehicle, a transmission device disposed coaxially with the output shaft of the engine, and a transmission device disposed on the output side of the transmission of the vehicle. a transfer device that transmits power in the lateral direction; a propeller shaft connected to the output side of the transfer device and extending parallel to the output shaft of the engine; and a propeller shaft connected to the output side of the propeller shaft to transmit driving force to the left and right wheels. a case member that covers the transfer device and the transmission device and has a vertical case portion that extends in the longitudinal direction of the vehicle; and a horizontal case portion that extends from the vertical case portion in the lateral direction of the vehicle; A mounting member for a transmission device that is attached to a bent portion formed by a vertical case portion and a horizontal case portion of the member, and a connecting member that extends substantially parallel to the propeller shaft and connects the differential device and the case member. A vehicle power unit structure featuring: 2. A power unit structure for a vehicle, wherein the mount member is constituted by a bracket and a rubber bushing, and the bracket connects the vertical case portion and the horizontal case portion of the transfer device.