KR960014064B1 - Fitting construction of engine mount bracket - Google Patents

Abstract

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Description

Attachment Structure of Engine Mount Bracket

1 is a plan view showing an engine mount bracket of an embodiment according to the present invention.

2 is a side view showing the engine mount bracket of the embodiment according to the present invention.

3 is a side view showing the engine mount bracket of the embodiment according to the present invention.

4 is a plan view showing the connection of the anti-vibration rubber device and the engine by the engine mount bracket of the embodiment according to the present invention.

5 is a diagram showing an amplification factor of engine vibration in the embodiment according to the present invention.

6 is a plan view showing an engine mount bracket of a second embodiment according to the present invention.

7 is a plan view showing the engine mount bracket of the embodiment according to the present invention.

8 is a schematic diagram showing the attachment of the engine front cover of the embodiment according to the present invention.

9 is a schematic diagram showing the attachment of the engine mount bracket of the embodiment according to the present invention.

10 is a diagram showing moments related to engine mount brackets of the embodiment according to the present invention.

Fig. 11 is a diagram showing moments related to engine mount brackets of the embodiment according to the present invention.

* Explanation of symbols for main parts of the drawings

1a: Arm 1: Engine Mount Bracket

2: engine block 2a: shear surface

3: Attachment part 3a, 4b, 6a of discharge rubber device: Mounting hole

4: engine front cover 4a: flange portion

4c: face 4d: end

5: Cover Attachment 6: Attachment to Engine Block

7: Attaching bolt 8: Discharge rubber device

8a: outer cylinder 9: chain

10: support pillar 10a: fitting hole

11: attachment bolt 12: frame of the body

13: Stay 14: Rib

A, B, C: Engine attachment point M: Mass

R _A , R _B , R _C : Reaction force X: Interval

8: displacement of the anti-vibration rubber device 9 side

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine mount bracket for a dustproof rubber device and an engine when elastically supporting an engine mounted in a lateral direction on a vehicle body, and in particular, an attachment structure of an engine mount bracket used for installing an engine front end portion. It is about.

In the conventional engine mount bracket, for example, as described in Japanese Patent Application Laid-Open No. 62-118734, the main body of the engine mount bracket is formed in an L-shape or the like, and one side of the attachment piece is connected to the engine outer wall. It is attached by bolt fixing to the engine block which comprises.

One of the attachment pieces is attached by touching the engine block constituting the outer wall of the engine and bolting it.

Further, the outer cylinder side of the anti-vibration rubber device is bolted to the tip end side of the other mounting piece portion of the engine mount bracket.

The anti-vibration rubber device is composed of a discharge rubber sandwiched between an outer cylinder and an inner cylinder, and the inner cylinder side is elastically prevented from the vehicle body by attaching the inner cylinder side to the vehicle body by an engine mount bracket on the vehicle body side. have.

In addition, since the reinforcing ribs are provided in the engine mount bracket, the rigidity is improved to suppress resonance caused by engine vibration.

As described above, in the attachment structure of the conventional engine mount bracket, all the attachment points on the engine side are set in the engine block so as to extend laterally from the engine block, and the anti-vibration rubber device is attached to the front end of the extension direction.

For this reason, an external force is input from the anti-vibration rubber device to the engine mount bracket by the relative motion between the vehicle body and the engine due to the engine vibration, and the input force is used to close the gap between the anti-vibration rubber device and the engine block. As the length of the arm, the load is applied to the attachment point on the engine side, and the wider the gap, the greater the reaction force generated at the attachment point, which becomes a severely disadvantageous condition, and the resonance frequency so as not to resonate with the engine noise. In view of increasing the area, the conditions are disadvantageous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an attachment structure for reducing the reaction force generated at the engine attachment point and increasing the resonance frequency range with respect to the engine attachment portion of the engine mount bracket. It is aimed at.

In order to achieve the above object, the engine mount bracket of the present invention is an engine mount bracket in an engine mount bracket for connecting a dustproof rubber device attached to the vehicle body side and a front end portion of the engine block, in the engine side attachment structure. A plurality of attachment points are set on the block to support the engine mount bracket on the engine block, and an attachment point is also set on the engine front cover which protrudes from the front end face of the engine block.

At this time, the tip of the spherical bolt may be attached to the engine block when the engine mount bracket and the engine front bolt are fixed.

The engine front cover may be provided with a support pillar extending from the attachment point of the engine mount bracket toward the engine block, the tip end of which being able to contact the engine block, and having the inside of the support pillar pass through the attachment bolt. .

Since the engine front cover protrudes from the front end face of the engine block, when viewed from the anti-vibration rubber device attached to the other end side of the engine mount bracket, the distance to the engine front cover is shorter than the front face of the engine block.

In view of this point, the present invention greatly reduces the reaction force input to the engine-side attachment portion by taking a part of the engine-side attachment point of the engine mount bracket on the engine front cover, and thus the engine-side attachment of the engine mount bracket. Improve the stiffness of wealth

In this case, the engine is elastically supported by the vehicle body by the engine mount bracket and the anti-vibration rubber device, and the engine vibration is input to the anti-vibration rubber device through the engine mount bracket, whereby the engine is absorbed by the anti-vibration rubber device. Although the vibration transmission is reduced on the side, at this time, a relative force is generated between the vehicle body and the engine by the vibration of the engine, and a predetermined force is input from the anti-vibration rubber device to the engine mount bracket. The engine mount bracket is vibrated at a predetermined frequency by the force, and the strength is required at the point of attachment on the engine side so as to withstand it.

The force applied to the attachment point on the engine side is input as a moment due to an external force from the anti-vibration rubber device. However, in the present invention, a part of the attachment point is taken as the engine front cover close to the distance from the anti-vibration rubber device as described above. As a result, a rotational force around the engine block side attachment point due to the force from the anti-vibration rubber device is mainly obtained at the engine front cover side attachment point.

The moment applied to the attachment point on the engine front cover side has a shorter arm than the engine block side, and therefore it is only required to receive a small force as compared with the case on the attachment point on the engine block side. do.

Further, the engine mount bracket has a form of one support protrusion because one end is strongly coupled to the engine side and the other end is elastically supported by the anti-vibration rubber of the anti-vibration rubber device.

At this time, for example, assuming that the stiffness of the engine mount bracket is constant, the second moment of the cross section of the engine mount bracket is set to I, the Young's module is set to E, and the input input from the anti-vibration rubber device is set to P. By the force P, the displacement δ of the anti-vibration rubber device side is represented by the following equation.

Here, X is the space | interval (arm length) between a dustproof rubber apparatus and an engine side attachment part.

As can be seen from this equation (1), since the displacement of the anti-vibration rubber device due to the attachment point on the small engine front cover side of X is small, the attachment point on the engine front cover side is smaller than the attachment point on the engine block side. It can be seen that the force mainly due to the external force is loaded.

For example, as shown in FIG. 9, the engine block side attachment point of an engine mount bracket is made into two points of A and B, the engine front cover side attachment point is made into a C point, and Y direction between ABs. The distance in the Y direction between a and AC is c, and the distance in the X direction from the anti-vibration rubber device to the engine block side attachment point is L1 and the X from the anti-vibration rubber device to the engine front cover side attachment point. When the distance in the direction is set to L2 and the external force input to the engine mount bracket from the anti-vibration rubber device is set to F when the engine is shaken in the Y direction by a roll or the like, as shown in FIG. 10, point A is shown. Assuming that F is input to M as the moment of rotation center, in the conventional engine mount bracket, with respect to point B,

Although reaction force of is input, in this invention, with respect to k point which is an attachment point of an engine front cover side,

Reaction force is input.

This reaction force (R _C ) takes the attachment point (D) at a position b away from the engine block, and inputs only a small force as small as (L2 / L1) compared to the reaction force input at the point D. Since there is a front cover, the attachment point is difficult to take at point D.

In addition, in the case where F is input as the moment with the point B as the center of rotation, as shown in FIG. 11, in the conventional engine mount bracket, with respect to the point A,

Although reaction force of is input, in the present invention,

_{F · L1 = R A · a} + R C · (ca)

And point B becomes the center of rotation,

_{R A · a = R c ·} (ca)

Where the equation is

_{F · L1 = 2 · R A} · a = 2 · R c · (ca)

Appears. therefore,

Reaction force is input to A point and B point, respectively.

If the spring constant of the engine mount bracket is k, in the above formula (1),

Appears.

In addition, if the frequency generated by the vibration generated in the engine mount bracket is f,

2πf = ω = (k / M) ^1/2

Because it may appear as

Appears.

Here, M is a dustproof rubber device.

As can be seen from this equation (3), the attachment point is also applied to the engine front cover as compared with the conventional case in which all attachment points are attached to the engine block. It can be seen that.

In general, the resonance frequency region generated in the engine mount bracket is set high so that the resonance point does not occur in the engine rotational speed region, and the amplification of the engine vibration sound caused by the bracket resonance is suppressed. The high range is effective for suppressing amplification of engine vibration sounds.

In addition, as described in claim 2, when the engine mount bracket is bolted to the engine front cover, the bolt that penetrates the front cover with the bolt is also fixed to the engine block, thereby providing the engine front cover to the engine block. The attachment point is increased, and the attachment rigidity of the engine front cover is improved, thereby increasing the resonance point of the engine front cover, thereby making it possible to lower the amplification rate of noise from the chain covered by the engine front cover.

In particular, the engine front cover usually has a flange portion on the outer surface that abuts on the engine block as an attachment point to the engine block, and a surface portion facing the engine block front end surface with a predetermined space is freely capable of membrane vibration. However, as described above, by fixing the engine mount bracket to the surface portion, the membrane vibration of the engine front cover can be lowered, and this surface portion can be further lowered by being fixed to the engine block.

At this time, since the attachment bolt crosses the space between the engine front cover and the engine block, for example, the engine front cover itself and the engine mount bra are provided by providing a support column as described in claim 3. Reinforcing the attachment point of the ket further suppresses the film vibration of the face portion of the engine front cover and improves the attachment strength of the engine mount bracket to the engine front cover by inserting the attachment bolt into the support pillar.

EXAMPLE

An embodiment of the present invention will be described with reference to the drawings.

The engine of the present embodiment is assumed to be mounted on the vehicle body in a state of being placed laterally.

As shown in FIG. 1, the engine mount bracket 1 of this embodiment is attached to the front end face 2a of the engine block 2, extends outward in the vehicle width direction, and is equipped with an anti-vibration rubber device at the leading end thereof in the extension direction. The attachment part 3 is formed, and the arm 1a protrudes laterally from the extension side end side toward the engine front cover 4 surface, and the cover attachment part 5 is provided at the tip end of the arm 1a. ).

The attachment portion 6 of the engine mount bracket 1 to the engine block 2 is composed of three attachment holes 6a bored in the horizontal direction as shown in FIGS. 2 and 3. The bolts are fixedly attached to the front end face 2a of the engine block 2 by attachment bolts 7 passing through the three attachment holes 6a.

Moreover, as shown in FIG. 1, the attaching part 3 of the anti-vibration rubber apparatus 8 side is comprised by the horizontal horizontal part which an adhesion surface faces upward, and has three horizontal parts which an axis faces in the up-down direction. The attachment hole 3a is drilled.

Then, as shown in Figs. 3 and 4, the attachment portion provided in the outer cylinder 8a of the anti-vibration rubber device 8 is engaged and bolted through the attachment hole, so that the anti-vibration rubber device 8 is the engine. It is attached to the mount bracket 1.

In addition, the front face 2a of the engine block 2 is covered with a chain 9 so that the engine front cover 4 is attached via the flange portion 4a, and the engine front cover 4 is provided. ) Is fitted with the cover 5 of the engine mount bracket 1.

In the cover attachment part 5, one attachment hole which drilled the shaft horizontally toward the engine block 2 side is drilled.

The engine front cover 4 also has a support pillar 10 extending coaxially with the attachment hole and extending toward the engine block 2 coaxially from the attachment hole 4b. Is installed.

The supporting column 10 is provided with an insertion hole 10a extending through the axial direction through which the attachment bolt 11 can penetrate.

The cover attachment portion 5 is attached to the engine front cover 4 by an attachment bolt 11 fitted to penetrate the attachment hole of the cover attachment portion 5 and the support pillar 10 of the engine front cover 4. ) And the engine block 2 are fastened together and fixed.

The anti-vibration rubber device 8 is provided with an anti-vibration rubber between the outer cylinder 8a and the inner cylinder, the shaft of which is arranged in a substantially concentric shape in the front-rear direction of the vehicle, and the inner cylinder side is formed by the frame of the vehicle body ( 12) is attached.

13 is a stay and 14 is a rib which reinforces the engine mount bracket 1.

In addition, the rear end of the engine block 2 is also attached to the vehicle body side via an engine mount bracket and an anti-vibration rubber device (not shown), so that the engine is elastically supported by the vehicle body.

When the vibration of the engine is input to the anti-vibration rubber device 8 through the engine mount bracket 1, the anti-vibration rubber of the anti-vibration rubber device 8 absorbs the vibration and lowers the transmission of vibration to the vehicle body side. .

At this time, the engine mount bracket 1 is shaken by causing relative motion between the vehicle body and the engine due to the vibration or roll of the engine. As a result, a predetermined force is relatively input to the engine mount bracket 1 from the anti-vibration rubber device 8, and the strength of the engine mount bracket 1 due to the force to withstand vibration is increased on the engine side. Required before attachment.

The moment by the input force is the arm of the moment which is an interval of the X direction (vehicle width direction) from the center point M of the anti-vibration rubber device 8 to the engine side attachment points A, B, and C. However, in this embodiment, since the engine front cover 4 closer to the dustproof rubber device 8 than the engine block 2, part C of the attachment point of the engine mount bracket 1 is taken. The length of the arm of the moment is shorter, and the reaction force input to each attachment point to this moment is smaller than before.

To explain this, the engine mount bracket 1 is seen as one support beam because one end is strongly coupled to the engine side and the other end is elastically supported by the anti-vibration rubber of the anti-vibration rubber device 8.

For simplicity, assuming that the rigidity of the engine mount bracket 1 is constant, the secondary moment of rotation of the engine mount bracket 1 is set to I and the Young's modulus is E, which is inputted from the anti-vibration rubber device 8. When the force is P, the displacement δ on the dustproof rubber device 8 side is represented by the following equation by the force P.

Here, X is the space | interval (arm length) of the X direction between the dustproof rubber device 8 and the engine side attachment part.

As can be seen from this equation, since the displacement of the anti-vibration rubber device 8 due to the attachment point C on the small engine front cover 4 side of X is smaller, it is smaller than the attachment point on the engine block 2 side. It can be seen that the moment is mainly applied to the attachment point on the engine front cover 44 side.

For example, the space | interval in the Y direction between the attachment points AB of the engine block 2 side is 20 cm, and the space | interval in the Y direction between AC is 70 cm, and the attachment point of the engine block 2 side from the anti-vibration rubber device 8 The distance in the X direction to (A) and (B) is 90 cm, and the distance in the X direction from the anti-vibration rubber device 8 to the attachment point C on the engine front cover 4 side is 20 cm. When the external force input to the engine mount bracket 1 from the anti-vibration rubber device 8 is set to 10 Kgf when it is shaken in the Y direction, assuming that 100 Kgf is input as the moment with the attachment point A as the rotation center. In the conventional engine mount bracket which does not take the attachment point C on the engine front cover 4, with respect to the attachment point B,

Reaction force is entered,

In the present embodiment, with respect to the attachment point C on the engine front cover 4 side

The reaction force is input, the reaction force does not occur of 3/50 as compared with the conventional R _B.

This reaction force R _C is smaller by (20/90) = (2/9) even when the attachment point D is taken on the engine block 2 side by 70 cm from the attachment point A. If it is assumed that 1000 Kgf is applied as the moment centering on the attachment point B, and the attachment point C is not taken on the engine front cover 4,

Although reaction force of is inputted, in this embodiment,

_{1000 · 90 = R A · 20} + R C · (70-20)

And the attachment point B becomes the center of rotation,

_{R A · 20 = R c ·} (70-20)

Where the formula is

_{1000 · 90 = 2 = R A} · 20 = 2 · R C · (70-20)

Appears. therefore,

The reaction force of each, are input to the respective attachment points A, C is reduced by the reaction force of this embodiment R _A to (1/2), R _c to (1/5) compared to a conventional R _A.

In this way, in the engine mount bracket 1 of the present embodiment, the reaction force generated at each engine side attachment point becomes small, and when viewed in rigidity, the design of the engine side attachment portion becomes easy.

Moreover, if the spring constant of the engine mount bracket 1 is set to K, from the above formula (1),

Appears.

In addition, if the frequency generated by the vibration generated in the engine mount bracket 1 is f,

2πf = ω = (k / M) ^1/2

Because it may appear as

Appears.

Where M is the mass of the anti-vibration rubber device 8.

As can be seen from this equation (3), compared to the conventional case where all the attachment points are taken to the engine block 2, the force of the present embodiment which also takes the attachment points to the engine mount bracket 4 is equal to the interval ( Since X) becomes small, it can be seen that the resonance frequency region becomes high.

As a result, the resonance frequency region of the engine mount bracket 1 can be set high, and the resonance point of the engine mount bracket can be set so that the resonance point does not occur in the engine use rotation region, whereby amplification of the engine vibration sound caused by the bracket resonance can be suppressed. In addition, the amplification suppression effect of the engine vibration sound is improved.

In fact, when the attachment point is set to C on the engine front cover 4 as in the present embodiment, and when the attachment point is not set on the engine front cover 4 for comparison, When measured, the result as shown in FIG. 5 was obtained.

This is virtually measured by taking the X axis in the vehicle front and rear directions, the Y axis in the vehicle width direction, and the Z axis in the vertical direction, and the solid line sets the attachment point C to the engine front cover 4 based on the present embodiment. The broken line shows a case where the point of attachment is not attached to the engine front cover 4 for comparison.

As can be seen from this figure, by setting the attachment point C in the engine front cover 4, it can be seen that the amplification factor of the engine vibration is low.

In particular, the vibration amplification ratio in the X and Y directions is significantly low, and thus the effect is large in reducing noise during acceleration.

In addition, when bolting the engine mount bracket 1 to the engine front cover 4, the bolt 11 penetrates the engine front cover 4 and the front end of the bolt 11 is connected to the engine block 1. ), The attachment point to the engine block 2 with respect to the engine front cover 4 increases, and the resonance point of this engine front cover 4 also becomes high.

This increases the resonance point with the noise from the chain 9 covered by the engine front cover 4, thereby lowering the amplification of this noise.

In general, the engine front cover 4 is capable of freely vibrating the surface portion 4c in which the flange portion 4a of the outer circumferential portion thereof faces the front end surface 2a of the engine block 2 with a predetermined space. However, as described above, by fixing the surface portion 4c, the vibration of the surface portion 4c of the engine front cover 4 is further suppressed, and the inside of the mounting bolt 11 penetrates the engine mount bracket ( The attachment to the engine front cover 4 of 1) is made firm.

Moreover, in order to improve the engagement of the cover attachment part 5 of the engine mount bracket 1 with this engine front cover 4, as shown in FIG. 6, the edge part 4d is attached to this attachment part. May be formed or a recess may be formed.

In the above embodiment, the attachment bolt 11 penetrates the engine front cover 4 and is attached to the engine mount bracket 1 and the bolt engine block 2, but as shown in FIG. Only the engine front cover 4 and the engine mount bracket 1 may be bolted.

In this case, of course, the attachment rigidity of the cover attachment part 5 of the engine mount bracket 1 is lower than in the above embodiment.

In fact, in order to confirm the noise reduction situation of the chain 9, by measuring the noise level at a position of 1 m from the engine block front face 2a with respect to the engine rotation speed, the result as shown in Fig. 8 is obtained. lost.

This measurement measures the case where the engine mount bracket 1 is bolted only to the engine front cover 4 and the case where the support pillar 10 is installed and fastened together to the engine block 2 together. Only the engine front cover 4 is bolt-fastened, and the broken line shows the case where it was fastened together with the engine mount bracket.

As can be seen from this figure, it can be seen that the chain noise reduction is improved by fastening together to the engine block 2.

In the above embodiment, only one attachment point is provided for the engine front cover 4, but if no interference with the chain 9 or the like occurs, various attachment points are placed on the engine front cover 4. It may be set.

In the above embodiment, the attachment bolt 11 penetrates the attachment hole of the engine mount bracket 1 and the engine front cover 4, and the tip end of the attachment bolt 11 is screwed into the engine block 2. On the contrary, the head side of the attachment bolt 11 is fixedly attached to the engine block 2 side, so that the support pillar 10 of the engine front cover 4 is attached to the shaft portion of the bolt 11. It is also suitable for the attachment structure in which the nut is screwed to the distal end thereof.

In the above embodiment, the mounting bolt 11 is only fitted to the support pillar 10 or the like of the engine front cover 4, but the female screw is provided on the support pillar 10 or the like, and the attachment bolt 11 is provided. And the support column 10 may be integrally screwed together.

As described above, in the attachment structure of the engine mount bracket of the present invention, only by studying the attachment position, the reaction force generated on the side attachment portion of the engine mount bracket becomes small, and the rigid design of the attachment portion is easy. do.

In addition, when the resonance frequency is high, and the resonance point for the engine vibration sound is increased, and it is possible to design such that the resonance does not occur in the normal engine speed range, the amplification of the engine vibration can be lowered.

Also, by constructing as in claim 2 or 3, the stiffness of the engine front cover is also improved to increase the resonance point for noise such as chain noise, thereby lowering the noise amplification for this noise, and to the engine front cover of the engine mount bracket. The attachment part of becomes firm.

Claims (3)

In the mounting structure on the engine side in the engine mount bracket connecting the anti-vibration rubber device 8 attached to the vehicle body and the front end face of the engine block 2, a plurality of attachment points are set on the engine block 2; The engine mount bracket 1 is supported on the engine block 2, and the attachment point is also set on the engine front cover 4 protruding from the front face 2a of the engine block 2. An engine mounting bracket mounting structure. 2. The mounting structure of the engine mount bracket according to claim 1, wherein the tip of the attachment bolt is attached to the engine block 2 when the engine mount bracket 1 and the engine front cover 4 are bolted. . The support according to claim 2, wherein the engine front cover (4) extends from the attachment point of the engine mount bracket (1) toward the engine block (2), the tip of which being able to contact the engine block (2). An installation structure of an engine mount bracket for installing a pillar (10) and fitting a bolt attached to the supporting pillar (10).