JP4977155B2 - Power unit mounting structure - Google Patents

Description

  The present invention relates to a mount structure for a power unit for a vehicle including an engine and a transmission.

  Generally, as a structure of the front part of the vehicle body, a structure that absorbs the collision energy received at the time of a vehicle collision by deformation of the vehicle body is adopted. In a so-called FF vehicle equipped with a horizontal power unit including an engine and a transmission, vibration is generated in the front-rear direction due to the torque reaction force (input load) of the engine. As a measure to prevent such vibration in the front-rear direction, a torque rod extending in the front-rear direction of the vehicle body is provided, and one end of the torque rod is elastically supported by the vehicle body frame of the shock absorbing structure, and the other end is elastically supported by the power unit. Techniques for making them disclosed are disclosed.

  However, since the torque rod is arranged so as to extend in the longitudinal direction of the vehicle, when the body frame of the shock absorbing structure is deformed at the time of collision, the torque rod functions like a tension rod, and the shock absorbing stroke and engine There was a problem that the separability between the vehicle body frame and the vehicle body frame could not be sufficiently secured, and the shock absorption by the vehicle body frame was hindered.

  Therefore, normally, a torque rod that functions to prevent vibration in the front-rear direction due to engine torque reaction force (input load) and that is broken only at the time of collision and does not hinder shock absorption due to frame deformation is provided. A power unit mounting structure is disclosed (see Patent Document 1).

Japanese Patent Laid-Open No. 2003-2070 (FIG. 4)

  However, in the power unit mounting structure equipped with the conventional torque rod, the strength to suppress the torque reaction force (input load) received from the engine and the breaking strength required at the time of collision are close to the input load and direction, It may not be compatible. In particular, in the case of an engine that generates high output instantaneously, the torque reaction force (input load) at the time of driving the engine is further increased, and the input load necessary for breakage is closer and compatible. There is a problem that it becomes more difficult.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a power unit mounting structure capable of achieving both strength for suppressing an input load from an engine and breaking strength required at the time of a collision. .

  The present invention provides a power unit mounting structure in which a power unit including an engine and a transmission is attached to a vehicle body via a mounting member. The mounting member extends in the front-rear direction of the vehicle body and is formed on a vehicle body frame including an impact absorbing member. An elastic support portion provided, a bracket elastically supported by the elastic support portion and supporting the power unit behind the elastic support portion, and extending in the front-rear direction of the vehicle body and vibrating in the front-rear direction of the power unit A torque rod elastically supported by the bracket via a connecting member, and the bracket and the connecting member in a state where the torque rod is positioned between the bracket and the front of the elastic support portion. A stiffener for connecting the stiffener to the bracket. Rigidity than bets is characterized by being configured so as to form low.

  According to the present invention, when a load at the time of collision is input, the stiffener having low rigidity is deformed and the collar of the torque rod falls down, so that the bending stress due to the rotational moment is applied to the rod portion of the torque rod. This occurs and the fragile portion with low rigidity of the torque rod is broken by this bending stress. As a result, the torque rod does not function as a tension during a collision, and the shock absorbing stroke of the vehicle body frame can be increased. Therefore, the impact absorption by the body frame is not hindered.

  According to the present invention, it is possible to achieve both the strength to suppress the input load from the engine and the breaking strength required at the time of collision.

It is a top view which shows the mount structure of the power unit of this embodiment. It is a disassembled perspective view which shows the mount member in this embodiment. It is a perspective view which shows the state after the assembly of the mount member in this embodiment. It is a side view which shows the mount structure of the power unit of this embodiment. (A) is sectional drawing when a torque rod is assembled | attached normally, (b) is sectional drawing in the case of incorrect assembly, (c) is sectional drawing of the conventional structure as a comparative example.

  As shown in FIG. 1, the mount structure of the power unit 10 of this embodiment is configured such that a power unit 10 including an engine 11 and a transmission 12 is attached to a vehicle body 1 via a mount member 20.

  The front portion of the vehicle body 1 has a crushable structure, and includes a side frame 2 (only the right side is shown) and a damper housing 3 (only the right side is shown) on both sides in the vehicle width direction (left and right direction). The side frame 2 is configured by an impact absorbing member that absorbs an impact force by being deformed at the time of collision, extends in the front-rear direction, and is positioned at a substantially central portion in the height direction (see FIG. 4). The damper housing 3 is configured to accommodate a front suspension including a damper, a coil spring, an arm, and the like.

  The power unit 10 is of a horizontal type in which an engine 11 is provided on the right side and a transmission 12 is provided on the left side.

  The mount member 20 is configured by combining an elastic support portion 21, a bracket 22, a torque rod 23, and a stiffener 24, and the elastic support portion 21 is on the side frame 2, the bracket 22 is on the power unit 10, and the torque rod 23. Are respectively attached to the vehicle body fixing brackets 4 of the damper housing 3.

  As shown in FIG. 2, the elastic support portion 21 has a function of attenuating vertical vibration received from the power unit 10, and an elastic material (not shown) such as rubber inside a cylindrical case 21 a formed in a cylindrical shape. ) Is filled. Further, the case 21a is formed with a pair of flange portions 21b, 21b having bolt holes (not shown) on the side surfaces in the front-rear direction, and the upper surface of the side frame 2 via the fastening bolts B1, B1, B1, B1. A case 21a is fixed to the case. Also, the elastic support portion 21 is formed with a mounting bolt B2 supported by an elastic material (not shown) protruding from a hole 21c formed on the upper surface of the case 21a. It is fixed.

  Further, the elastic support portion 21 includes a stopper 25 that restricts vertical vibrations by the power unit 10 within a predetermined range. The stopper 25 is attached to the case 21a, and a through hole 25a1 is formed through which the mounting bolt B2 protruding upward from the elastic support portion 21 is inserted. The mounting bolt B2 inserted through the through hole 25a1 is fixed by being screwed to the lower surface of the bracket 22.

  The bracket 22 is formed by casting a metal material such as iron, and extends in the front-rear direction of the vehicle body 1. The bracket 22 includes a stiffener mounting portion 22a to which a stiffener 24, which will be described later, is mounted at the front end portion, a torque rod mounting portion 22b to which a torque rod 23 is mounted behind the stiffener mounting portion 22a, and the torque rod mounting portion 22b. A power unit attachment portion 22c to which the power unit 10 (engine 11) is attached is provided on the rear side.

  The stiffener mounting portion 22a has columnar fixing portions 22a2 and 22a2 that are formed to protrude upward, and a screw hole 22a1 is formed on the upper surface of each fixing portion 22a2.

  The torque rod attachment portion 22b is formed with a screw hole 22b1 into which a connection bolt (connection member) B5 for attaching one end (front end) of the torque rod 23 described later is screwed.

  The power unit mounting portion 22c is formed with bolt insertion holes (not shown) arranged in the front-rear direction, and via a flange (not shown) formed on the right side surface of the power unit 10 via fastening bolts B4 and B4. To be fixed.

  The bracket 22 has a curved portion 22d that curves inward in the vehicle width direction (the left side in FIG. 1) between the torque rod mounting portion 22b and the power unit mounting portion 22c, and the power unit mounting portion 22c is the side frame 2. It is located on the inner side in the vehicle width direction than the inner side surface.

  The torque rod 23 has a function of suppressing vibration in the front-rear direction when the engine 11 is driven. For example, by casting a metal material such as iron, the torque rod 23 has a small-diameter cylindrical body 23a, a large-diameter cylindrical body 23b, and a cylindrical body 23a. And the rod part 23c which joins the cylinder body 23b are comprised integrally.

  The torque rod 23 has a collar 23a1 smaller in diameter than the cylinder 23a in the center of the cylinder 23a and a collar 23b1 smaller in diameter than the cylinder 23b in the center of the cylinder 23b. The cylinder 23a and the collar 23a1. An elastic body 23a2 such as rubber is fixed in the space between the elastic body 23b2 and an elastic body 23b2 such as rubber is fixed in the space between the cylindrical body 23b and the collar 23b1. Incidentally, the elastic body 23a2 is formed so as to penetrate part of both sides in the vehicle width direction, and the elastic body 23b2 is formed to extend diagonally from the collar 23b1 to both sides in the vehicle width direction. In addition, the shape of these elastic bodies 23a2 and 23b2 is not limited to this embodiment.

  The rod portion 23c has a thin portion 23c1 that is disposed so that its axial direction is directed in the front-rear direction of the vehicle body 1, and a portion thereof is formed in a thin shape. The thin portion 23c1 is formed in a substantially T shape along the peripheral edge of the cylindrical body 23a and toward the cylindrical body 23b at the center. By providing such a thin part 23c1, a part of the torque rod 23 is a weak part having a lower rigidity than the other part.

  In the torque rod 23, the means for forming the fragile portion is not limited to the thinning method, and may be configured by combining members of different materials having low rigidity.

  The stiffener 24 is formed in a substantially triangular shape by bending a metal plate material, bolt insertion holes 24a1 are formed in the corner 24a at the rear end, and bolt insertion holes 24b1, 24b1 in the left and right corners 24b, 24b at the front end. Is formed. In addition, the stiffener 24 is configured to be bent downward in an L shape at the corners 24b and 24b.

  As shown in FIGS. 2 and 3, the connecting bolt B5 is inserted into the bolt insertion hole 24a1 of the stiffener 24 and the collar 23a1 of the torque rod 23 and screwed into the screw hole 22b1 of the torque rod mounting portion 22b of the bracket 22. Fixed. The bolts B3 and B3 are inserted into the bolt insertion holes 24b1 and 24b1 of the stiffener 24, and are screwed and fixed to the fixing portions 22a2 and 22a2. Thereby, one end (front end) of the torque rod 23 is elastically supported by the bracket 22.

  The torque rod 23 has a fastening bolt B6, a screw insertion hole (not shown) formed in one plate portion 4a of the vehicle body fixing bracket 4, a collar 23b1, and a screw insertion formed in the other plate portion 4b. Each is inserted through a hole (not shown) and connected via a nut N. Thereby, the other end (rear end) of the torque rod 23 is elastically supported by the vehicle body 1.

  Next, the effect | action in the mount structure of the power unit 10 of this embodiment is demonstrated with reference to FIG. In a normal case, first, as indicated by a broken line arrow in FIG. 4, a torque reaction force (input load) T received from the power unit 10 (engine 11) acts on the rear end portion of the bracket 22. The input load in this case is transmitted to the torque rod 23 through the power unit attachment portion 22c and the torque rod attachment portion 22b of the highly rigid bracket 22 and further through the corner portions 24a and 24b in the stiffener 24. At this time, the input of the stiffener 24 is below the deformation strength. Therefore, the torque rod 23 is not damaged by the input load due to the torque reaction force T, and the torque reaction force T due to the torque rod 23 can be reliably attenuated.

  On the other hand, when the vehicle collides, the collision load F acts on the front end portion of the bracket 22 as shown by a solid arrow in FIG. When such a collision load is input, the bracket 22 having sufficient rigidity is received without being deformed, and the stiffener 24 having low rigidity is immediately deformed, so that the upper portion of the collar 23a1 falls to the bolt B3 side. Then, a rotational moment M in the counterclockwise direction shown in the figure acts on the cylindrical body 23a of the torque rod 23. This rotational moment M acts as a bending load on the rod portion 23c. Therefore, in addition to the collision load F, the torque rod 23 also has a bending load due to the rotational moment M.

  Thus, when a bending load due to the rotational moment M acts on the torque rod 23, the thin portion 23c1 of the rod portion 23c becomes the fragile portion that is most easily broken. The fracture includes not only fracture but also plastic deformation exceeding elastic deformation such as buckling. When the vehicle collides, the thin portion 23c1 is subjected to a bending stress caused by the rotational moment M in addition to the axial stress caused by the collision load F. For example, the thin portion 23c1 is broken at the S point of the thin portion 23c1. When the torque rod 23 is broken, the torque rod 23 does not function as a tension, and the power unit 10 can move rearward. As a result, it is possible to ensure a long shock absorption stroke of the side frame 2 and sufficiently absorb the collision energy.

  In the present embodiment, only the upper right part of the vehicle has been illustrated and described, but the upper part on the left side is provided with a mount (corresponding to the elastic support portion 21) that attenuates vertical vibration, and the lower part on the right side. A mount (corresponding to the torque rod 23) for attenuating vibration in the front-rear direction of the power unit 10 is provided.

  By the way, the torque rod 23 has a characteristic difference in its vertical direction, and when the vertical shape difference is small, there is a possibility that the torque rod 23 is erroneously assembled upside down. That is, as shown in FIG. 5C, in the structure in which the connecting bolt B100 is inserted into the through hole 101s of the collar 101 and the screw groove b12 is screwed to the bracket 22, the torque rod 23 is assembled in either the upper or lower direction. Even so, the connecting bolt B100 can pass through the through hole 101s of the collar 101 and be screwed into the screw hole 22b1 of the bracket 22, and the torque rod 23 may be misassembled.

  Specific examples of the characteristic difference in the vertical direction mainly include the following depending on the holder shape of the torque rod 23 and the arrangement of the elastic bodies 23a2 and 23b2 provided on the cylindrical bodies 23a and 23b. it can. For example, (1) characteristic difference of failure mode at the time of collision, (2) vibration transmission characteristic difference of the engine 11, (3) stopper characteristic difference when the engine 11 swings, (4) durability characteristics of the elastic bodies 23a2 and 23b2. Differences, (5) assembly, detachability (productivity, maintainability) and the like can be mentioned. Incidentally, in the case of (1), there is a possibility that the intended breakage mode may not be achieved in the engine room at the time of a vehicle collision, as a problem when used in a misassembled state. In the case of (2), the vibration transmissibility deteriorates, and there is a risk that steering stability, riding comfort, noise and vibration will deteriorate. In the case of (3), the engine 11 does not have the intended displacement, and the steering stability, riding comfort, noise and vibration are deteriorated due to damage due to component interference in the engine room, abnormal noise, and a feeling of rocking of the engine 11. There is a risk. In the case of (4), the elastic bodies 23a2 and 23b2 of the torque rod 23 may be damaged early. In the case of (5), the torque rod 23 may be inverted upside down (erroneously assembled).

  Therefore, in the embodiment shown in FIG. 5A, the collar 23a1 and the connecting bolt B50 are configured to prevent erroneous assembly. The collar 23a1 is fixed to the torque rod 23 via an elastic body 23a2.

  The collar 23a1 is formed in a cylindrical shape, and has a through hole 23s in which a large-diameter hole 23s1 into which the connecting bolt B50 is inserted and a hole 23s2 having a smaller diameter than the hole 23s1 are continuously formed. ing. The large-diameter hole 23s1 is located on the proximal end side (stiffener 24 side) of the connection bolt B50, and the small-diameter hole 23s2 is located on the distal end side (bracket 22 side) of the connection bolt B50. That is, the through hole 23s of the collar 23a1 has a stepped portion P1 whose inner diameter is reduced in the middle of the through hole 23s from the side where the connecting bolt B50 is inserted.

  The connecting bolt B50 is a so-called flange bolt having a flange b1, and includes a large-diameter shaft portion b2 and a shaft portion b3 having a smaller diameter than the shaft portion b2. A thread groove is formed on the peripheral surface of the tip portion of the shaft portion b3. b4 is formed. That is, the connecting bolt B50 is formed with a stepped portion P2 whose outer diameter is reduced in the middle of the axial direction, the shaft portion b2 is fitted into the hole portion 23s1 of the collar 23a1, and the shaft portion b3 is a hole of the collar 23a1. It is configured to be fitted with the portion 23s2.

  In such a structure for preventing the wrong assembly of the torque rod 23, when it is assembled normally as shown in FIG. 5A, the collar 23a1 provided on the torque rod 23 is sandwiched between the bracket 22 and the stiffener 24. The connecting bolt B50 is inserted into the bolt insertion hole 24a1 of the stiffener 24 and the through hole 23s of the collar 23a1, and the screw groove b4 is screwed into the screw hole 22b1 of the bracket 22. In this case, the small-diameter shaft portion b3 of the connecting bolt B50 is fitted into the small-diameter hole portion 23s2 of the collar 23a1, and the large-diameter shaft portion b2 of the connecting bolt B50 is fitted into the large-diameter hole portion 23s1 of the collar 23a1. As a result, the connecting bolt B50 is inserted into the through hole 23s, and the screw groove b4 of the connecting bolt B50 is screwed into the screw hole 22b1 of the bracket 22, whereby the torque rod 23 is connected to the bracket 22 via the connecting bolt B50. Can be assembled to.

  In this way, the fitting shape of the collar 23a1 and the connecting bolt B50 is made an irregular shape with a step, and the assembly direction is uniquely (one direction) to prevent the torque rod 23 from being misassembled. Incidentally, as shown in FIG. 5B, when the torque rod 23 is turned upside down, the collar 23a1 is turned upside down so that the connecting bolt B50 is connected to the through hole 23s of the collar 23a1. Even if inserted, the stepped portion P2 of the connecting bolt B50 interferes with the opening of the through hole 23s of the collar 23a1, and the connecting bolt B50 cannot be inserted any more, and the torque rod 23 is prevented from being assembled incorrectly. become.

1 body 2 side frame (body frame)
DESCRIPTION OF SYMBOLS 10 Power unit 11 Engine 12 Transmission 20 Mount member 21 Elastic support part 22 Bracket 23 Torque rod 23a1 Collar 23c Rod part 23c1 Thin part 24 Stiffener B5 Connection bolt (connection member)

Claims (1)

In a power unit mounting structure in which a power unit including an engine and a transmission is attached to a vehicle body via a mounting member,
The mounting member is
An elastic support provided on a vehicle body frame extending in the front-rear direction of the vehicle body and comprising an impact absorbing member;
A bracket that is elastically supported by the elastic support portion and supports the power unit behind the elastic support portion;
A torque rod formed to extend in the front-rear direction of the vehicle body and attenuate vibrations in the front-rear direction of the power unit, and elastically supported by the bracket via a connecting member;
A stiffener for connecting the bracket and the connecting member in a state where the torque rod is positioned between the bracket and the bracket in front of the elastic support portion;
The power unit mounting structure, wherein the stiffener is formed to have lower rigidity than the bracket.

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