JPS6212418A - Support structure for horizontally laid power unit - Google Patents

Abstract

PURPOSE:To prevent first and second resilient support members for supporting the front and rear sections of a power unit from exciting vibration, by positioning these resilient support members such that the resilient center among them is positioned on the torque roll axis of the power unit. CONSTITUTION:A power unit 4 is composed of an engine 7, a transmission 8 and a differential gear integrally incorporated with the transmission 8. In this arrangement the power unit 4 is supported at its front and rear ends, resiliently by first and second resilient support members 11, 12 which are opposed in the longitudinal direction so that the torque axis of the power unit is laid there between and which are spaced from each other by a predetermined distance, and is supported at its both side sections by third and fourth resilient support members 13, 14 at positions which are spaced from each other by a predetermined distance in the direction of torque roll axis Z of the power unit. Further, the first and second support member 11, 12 are arranged so that the resilient center V among them is positioned on the torque roll axis Z.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a support structure for a horizontal power unit equipped with an engine, a transmission, and the like.

(Prior art) For example, in a front-engine, front-drive vehicle, the power unit consisting of the engine, transmission, etc. is placed horizontally in the engine room at the front of the vehicle with the engine's torque shaft (crankshaft) facing left and right of the vehicle. In this case, the main axis of inertia of the engine's rolling motion and the axis of rotation of the tire are parallel to each other, so that the torque reaction force due to the rotation of the tire acts directly on the rolling direction of the engine. do. For this reason, in vehicles equipped with the above-mentioned horizontally mounted power unit, the engine is supported by the vehicle body so that its own vibrations are less likely to be transmitted to the vehicle body, and the torque reaction force due to the rotation of the tires is also The uke is required to be supported so that it can be stopped.

If the engine is supported without this requirement being met, rotational vibrations around the principal axis of inertia will be transmitted to the car body when the engine is running at low speeds, especially when idling, while rotational vibrations around the torque roll axis will be transmitted to the car body when the engine is running at high speeds. , there are problems such as increased noise and worsened ride comfort.

Here, the above-mentioned torque roll axis is, as is well known, an axis determined by the torque axis where torque is generated and the principal axis of inertia, and is the rotation of the power unit when torque around the crankshaft is applied to the unrestrained power unit. The power unit rotates around the torque roll axis above the road when the engine rotates at high speeds, that is, when the forced vibration frequency of the power unit is sufficiently larger than the natural frequency and receives high-frequency torque fluctuations. It is something to do.

The main axis of inertia passes through the center of gravity of the power unit with respect to a horizontal axis parallel to the output shaft of the differential gear, and is inclined at an angle α of about 10° to 15° from the horizontal, and the torque roll axis passes through the center of gravity and is inclined at an angle α of about 10° to 15° from the horizontal. It is inclined with respect to the principal axis of inertia by an angle β having the relationship between α and the following equation.

tan β= (IX / IZ) ・tan α However, I is the moment around the principal axis of roll inertia, and Iz is the moment about the principal axis of yawing inertia, which is approximately vertical through the center of gravity, and generally Ix<Iz, so
α>β.

As a technique for preventing rotational vibration around the principal axis of inertia, the technique disclosed in Japanese Utility Model Application Laid-Open No. 57-135426 is known.

(Object of the Invention) An object of the present invention is to provide a support structure for a horizontal power unit that can prevent rotational vibration around the torque roll axis.

(Structure of the Invention) The present invention provides a support structure for a horizontal power unit that includes an engine, a transmission, etc., and has a torque shaft disposed in the lateral direction of a vehicle body, the torque shaft being connected to the vehicle body so as to elastically support the front and rear portions of the power unit. first and second elastic support members sandwiched in the front-rear direction and placed a predetermined distance apart; and third and fourth elastic supports placed a predetermined distance apart in the lateral direction of the vehicle body so as to elastically support both sides of the power unit. The first and second elastic support members are arranged such that their centers of elasticity are located on the torque roll axis.

(Effects of the Invention) In the support structure for a horizontal power unit of the present invention configured as described above, the elastic centers of the first and second elastic support members supporting the front and rear parts of the power unit are arranged so as to be located on the torque roll axis. Therefore, when the engine vibrates, especially when idling, no vibration moment is applied to these first and second elastic support members, and vibrations caused by these elastic support members can be prevented.

(Example) Hereinafter, a support structure for a horizontal power unit according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the arrangement of the power unit. As shown in the figure, a power unit mount member 3 is installed in the engine compartment 2 formed at the front of the vehicle body 1 in the longitudinal direction of the vehicle body (in the example shown, the vehicle body The front part is indicated by arrow F, and the rear part of the vehicle body is indicated by arrow R), and a power unit 4 is mounted on the member 3. Here, the mount member 3 is attached to the vehicle body 1 with bolts 6 through anti-vibration rubbers 5 at both front and rear ends 3a and 3b, respectively.
It is installed using 6.

On the other hand, the power unit 4 is composed of an engine 7, a transmission 8 attached to one side of the engine 7, and a differential gear device 9 integrated with the transmission 8. The differential gear device 9 is arranged horizontally so that X faces the left and right direction of the vehicle body 1, and the differential gear device 9
Drive shafts 10 and 10 extend in the left and right directions of the vehicle body, and left and right wheels (not shown) are connected to their ends.

As shown in FIGS. 1 and 2, the power unit 4 has first and second elastic support members 11 and 12 at its front and rear sides, and third and fourth elastic support members 13 at both sides. and 14 by said member 3
and are supported by the vehicle body 1, respectively.

Further, among the elastic support semi-recesses 11 to 14, the first and second elastic support means 11.12 are located at the rear end of the front QW 'fR and U differential gear device 9 of the transmission 8, that is, at the rear end of the The third and fourth elastic support means 13 and 14 are disposed at a predetermined distance apart from each other in the longitudinal direction of the vehicle, and elastically support the power unit 4 on the member 3. Similarly, the power unit 4 is elastically supported on the vehicle body 1 at each side, that is, at positions separated by a predetermined interval in the torque roll axis Z direction. Here, in this embodiment, the first elastic support member 11 (the same applies to the second elastic support member 12) connects the inner cylinder 15 and the outer cylinder 16 as shown in FIGS. The inner cylinder 15 is configured of a rubber bush consisting of an elastic rubber 17, and is attached to a bracket 18 (bracket 19 for the second elastic support member 12) fixed to the power unit 4.
is pivotally supported and the outer cylinder 16 is fixed to the mount member 3 via the attachment part 16a, thereby reducing the transmission of vibrations of the power unit 4 to the member 3, that is, to the vehicle body 1. ing. In the third and fourth elastic support members 13 and 14, the outer cylinder sides of the rubber bushes are fixed to the power plant 4 via brackets 13a and 14a, respectively.

The first and second elastic support members 11 and 12 are arranged such that the elastic center (2) between them is located on the torque roll axis Z, as shown in FIGS. 4 and 5. ing. The elastic centers of the first and second elastic support members are determined by the positions of both elastic members, the orientations of the two high and low elastic principal axes of both elastic members, and the spring constants in the biaxial directions, and by tuning these, the elastic centers (2) is located on the torque roll axis Z. This makes it possible to prevent vibrations from being caused by the first and second elastic support members 11 and 12. In addition, in the figure, symbol X indicates a torque axis, and symbol W indicates the center of gravity of the power unit 4, respectively.

[Brief explanation of drawings]

1 is a plan view of a support structure for a horizontal power unit according to an embodiment of the present invention, FIG. 2 is a front view of the support structure shown in FIG. 1, and FIG. 3 is a line taken along line III-- in FIG. 4 and 5 are cross-sectional views taken along line III, FIGS.
FIG. 3 is a schematic plan view and a schematic front view showing an elastic center between the first elastic support member and the second elastic support member. 1...Vehicle body 4...Power unit 11...First elastic support member 12...Second elastic support member 13...Third elasticity Support member 14... 4th - Elastic support member ■... Elastic center Fig. 4 Fig. 5

Claims (1)

[Claims] This is a support structure for a horizontally installed power unit that includes an engine, a transmission, etc., and has a torque shaft placed in the lateral direction of the vehicle body, and the torque shaft is sandwiched in the front and rear direction of the vehicle body so as to elastically support the front and rear parts of the power unit. first and second elastic support members arranged, and third and fourth elastic support members arranged at a predetermined distance apart in the lateral direction of the vehicle body so as to elastically support both sides of the power unit; A support structure for a horizontal power unit, wherein the second elastic support members are arranged such that their elastic centers are located on the torque roll axis.