JP2007069742A - Torque rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely control a breaking position and a breaking load by proving a breaking structure to a torque rod itself in a torque rod to be broken at a predetermined compression load at the time of collision. <P>SOLUTION: This torque rod 1 comprises a long rod part 5, and cylindrical parts 6 and 7 provided on both ends of the rod part. Fragile parts 12 and 15 are provided at portions where a maximum stress is generated by a compression load F1 and a tensile load F2 at the time of collision on an action axial line C of the cylindrical parts 6 and 7. When the compression load F1 or the tensile load F2 is applied at the time of collision, a large tensile stress is generated to the fragile parts 12 or 15. The cylindrical part 6 or 7 is surely broken at the fragile parts 12 or 15 by resultant tensile distortion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a torque rod used for connecting a power unit to a vehicle body. In particular, a part of the power rod is destroyed at the time of a collision, and the breaking position and the breaking load at this time can be controlled to be constant. About things.

A conventional torque rod includes a rod portion having a substantially rod shape and ring-shaped cylindrical portions provided at both ends thereof, and connects the vehicle body and the power unit in the front-rear direction via bushes supported by each cylindrical portion. It was.
In addition, the rod part is formed in a roughly diamond shape, and a bent part that forms a mountain shape is provided in the middle part, and when collision load is compressed and input to the rod part, stress is concentrated on this bent part to control fracture. A thing is also well-known (refer patent document 1).
Further, there is a yoke provided with a slit for reaching the bolt hole in the yoke portion for attaching the bush so that the bush is dropped at the time of collision (see Patent Document 2).

JP 2004-255967 A Japanese Patent Laid-Open No. 2004-243952

By the way, in the case of a general torque rod in which the rod portion has a substantially uniform cross section in the length direction, the breaking position is not constant, and the breaking load may be difficult to control. In addition, since the rod portion is originally a relatively high-strength member, a special structure as in Patent Document 1 is required to reliably break the rod portion at the time of collision.
In the case of Patent Document 2 in which a slit is provided in a yoke portion other than the rod portion, the strength of the yoke portion is reduced by the slit.
Therefore, the present invention can surely break the portion other than the rod portion by the load input at the time of collision, can control the breaking position and the breaking load to be constant, and does not cause a decrease in strength by providing a slit or the like. An object of the present invention is to provide a torque rod that can be used.

In order to solve the above-mentioned problem, claim 1 according to the torque rod of the present application includes a rod portion and bush mounting brackets provided at both ends thereof, and a power unit and a power unit via bushes supported by these bush mounting brackets. In the torque rod connected to the car body,
At least one side of the bracket for mounting the bush is a cylindrical portion, and the outer peripheral portion of the cylindrical portion is a portion overlapping with the action axis line connecting the load input points of both the brackets for mounting the bush. A fragile portion is provided in a site where the rupture occurs, and the cylindrical portion is destroyed starting from the fragile portion when a predetermined load is input.

  A second aspect of the present invention according to the first aspect is characterized in that the fragile portion is a concave portion provided on an arcuate curved surface on the outer periphery of the cylindrical portion, or a hole or a thin portion formed in the central axis direction of the cylindrical portion. And

  A third aspect of the present invention is characterized in that, in the first aspect, the fragile portion is provided on the rod portion side of the cylindrical portion, and is destroyed by a load at the time of a collision input to the rod portion in a compression direction. To do.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the rod portion is provided with a guide portion that obliquely intersects with an axial direction thereof, and an input portion of a compressive load that moves when the fragile portion is broken is disposed from the rod portion. It is characterized in that it is disengaged outside the action axis.

  According to a fifth aspect of the present invention, in the first aspect, the fragile portion is provided on a side opposite to the rod portion of the cylindrical portion, and is destroyed by a load at the time of a collision input to the rod portion in a pulling direction. Features.

  According to the first aspect of the present invention, in the outer peripheral portion of the cylindrical portion, a weak portion is provided on a portion where the tensile strain is generated by the load input on the action axis, and the cylindrical portion is caused by the tensile strain generated when a predetermined load is input. Was destroyed starting from the vulnerable part.

  Therefore, when a predetermined load is input to the cylindrical portion and applied in the longitudinal direction of the torque rod, if it is set to be broken from the fragile portion by the tensile strain generated along with the tensile stress concentrated on the fragile portion, By inputting a predetermined load at the time of collision, the cylindrical portion is reliably broken at the weak portion, and the breaking position becomes accurate. Also, the control of the breaking load becomes accurate. Moreover, it is possible to prevent the strength from being lowered by providing a slit or the like.

  According to the second aspect, the fragile portion is a concave portion provided on the arcuate curved surface on the outer periphery of the cylindrical portion, or a hole or a thin portion formed in the central axis direction of the cylindrical portion.

  According to the third aspect, since the fragile portion is provided on the rod portion side of the cylindrical portion, it can be accurately broken by the load at the time of collision input to the rod portion in the compression direction.

  According to the fourth aspect of the present invention, since the guide portion obliquely intersecting the axis is provided in the rod portion in the vicinity of the fragile portion, the compression load input portion that moves by breaking the cylindrical portion at the fragile portion is directed to the guide portion. If it reaches, it will be guided and moved away from the action axis of the rod part. For this reason, it is possible to avoid a situation where the input portion of the compressive load remains on the axis of the rod portion even after the torque rod is broken and the compressive load is continuously transmitted to the rod portion. In addition, after the cylindrical portion is broken, the transmission of the compressive load to the rod portion can be reliably interrupted.

  According to the fifth aspect, since the fragile portion is provided on the opposite side of the rod portion of the cylindrical portion, it can be accurately broken by the load at the time of collision input to the rod portion in the pulling direction.

  Hereinafter, an embodiment will be described based on the drawings. FIG. 1 is a schematic view showing a usage state of a torque rod. The torque rod 1 is a longitudinal member, and the power unit 3 and the vehicle body 4 are connected in a vibration-proof manner via bushes 2 provided at both ends in the longitudinal direction. The power unit 3 integrates the engine and the transmission, is mounted horizontally on the FF vehicle, and is mounted on the vehicle body side in an anti-vibration manner in the form of an inertia main shaft. The bush 2 in this example is configured as a side mount.

  The torque rod 1 is for the power unit 3 to restrict rolling around the inertia main shaft, and is arranged with its longitudinal direction directed in the longitudinal direction of the vehicle body so as to receive a compressive load F1 at the time of collision in the longitudinal direction. It has become. In this example, the torque rod 1 receives the compressive load F1 at the time of the collision by the power unit 3 that is arranged behind the power unit 3 and moves backward at the time of the collision.

  Here, expressions relating to various directions referred to in the present application are defined as follows. In the attached state of FIG. 1, the front-rear direction refers to the front-rear direction of the vehicle body. Further, a state in which the torque rod is viewed from above the vehicle body is viewed from the top surface, and a state viewed from the side of the vehicle body perpendicular to the torque rod is viewed from front. The left-right direction of the vehicle body in the top view is the horizontal direction or the thickness direction, and the width of the torque rod in this direction is the horizontal width or thickness. The vertical direction of the vehicle body in the front view is the vertical direction or the vertical direction, and the width of the torque rod in this direction is simply the width.

  2 is a perspective view of the torque rod 1, and FIG. 3 is a front view thereof. As shown in these drawings, the torque rod 1 includes a longitudinal rod portion 5 and cylindrical portions 6 and 7 provided integrally at both ends in the longitudinal direction. The rod portion 5 has a plurality of lightening holes 8 formed at appropriate intervals in the longitudinal direction. Each lightening hole 8 penetrates in the lateral direction. A partition wall 9 is formed between the adjacent hollow holes 8. Both end portions in the length direction of the rod portion 5 form a round shape to the cylindrical portions 6 and 7 and are continuously integrated.

  As shown in FIG. 3, the torque rod 1 is substantially symmetrical with respect to a longitudinal action axis C connecting the center points c1 and c2 of the cylindrical portion 6 and the cylindrical portion 7 (except for a guide portion 13 described later). . Each of the center points c1 and c2 is also an input point of a load at the time of collision. The action axis C is also the longitudinal axis of the rod portion 5 and is the center line of the width of the rod portion 5 in the state shown in FIG. Further, the action axis C is orthogonal to the center axes C1 and C2 (FIG. 2) passing through the center points c1 and c2 of the cylindrical portions 6 and 7.

  The cylindrical portions 6 and 7 are different in size. In this example, the cylindrical portion 6 on the power unit 3 side has a small diameter, and the cylindrical portion 7 on the vehicle body 4 side has a large diameter. Further, among the respective hollow holes 8, those adjacent to the cylindrical portion 6 are particularly referred to as end hole 10. An inner portion 11 of the cylindrical portion 6 faces the end hole 10, and a fragile portion 12 is formed on an arcuate curved surface of the outer peripheral portion in this portion.

  The fragile portion 12 is a substantially semicircular recess that opens into the end hole 10, and is located on the action axis C in the longitudinal direction of the rod portion 5. The inner part 11 forms a partition wall between the bush hole 6 a and the end hole 10 of the cylindrical part 6. Further, the partition wall 9 formed between the end hole 10 and the inner hollow hole 8 adjacent to the end hole 10 is a guide portion 13 having an inclined surface oblique to the action axis C. . The guide portion 13 is located on the opposite side of the inner portion 11 with the end hole 10 interposed therebetween.

A partition wall 14 forming a part of the cylindrical portion 7 is formed between the bush hole 7 a of the cylindrical portion 7 and the adjacent hollow hole 8. A fragile portion 15 is formed at the end of the torque rod on the action axis C at the outer peripheral portion of the cylindrical portion 7. The fragile portion 15 is the same as the fragile portion 12 and is provided on the outer side portion 16 of the cylindrical portion 7 on the action axis C.
The outer portion 16 is a portion on the outer peripheral portion of the cylindrical portion 7 that is opposite to the partition wall 14 of the rod portion 5 with the bush hole 7a interposed therebetween. It is formed as a recess opened to the direction.

  As is apparent from FIG. 2, these fragile portions 12 and 15 are each formed continuously over the entire width direction, and are preferably formed at the same time as the extrusion of the torque rod material described later.

  In FIG. 3, the cylindrical space of the cylindrical portion 6 has a bush hole 6a, and the bush 2 (FIG. 1) is attached thereto by baking. The bush 2 is a known member made of an anti-vibration rubber 18 with an inner cylinder 17 integrated at the center, and is attached to the power unit 3 (FIG. 1) by a connecting shaft (not shown) such as a bolt passing through the inner cylinder 17.

  The same applies to the cylindrical portion 7 side, and the bush 2 is provided inside the bush hole 7a and is attached to the bracket 4a of the vehicle body 4 via the bush 2 (FIG. 1). In addition, the bush 2 provided in the cylindrical part 6 or 7 may be provided with an outer cylinder, formed as an independent part of the cylindrical part 6 or 7, and press-fitted into the cylindrical part 6 or 7.

  FIG. 4 is an enlarged view of the cylindrical portion 6 and shows the states before (A) and after (B) destruction. As shown in A of this figure, when the compressive load F1 at the time of collision is applied to the point P on the inner peripheral side of the inner part 11 on the action axis C, the point Q near the fragile part 12 on the outer peripheral side is maximized. Stress is concentrated. A portion on the action axis C of the inner portion 11 including the point PQ is a stress maximum portion R where the stress becomes the largest when a compressive load is input on the cylindrical portion 6.

  A limit value is set for the strength of this portion so that it breaks when it is broken by a predetermined tensile strain caused by a tensile stress, and this limit value can be freely adjusted by the size of the fragile portion 12 or the like. Further, the predetermined stress corresponding to the limit value can be freely determined according to the load input at the time of collision. Accordingly, the torque rod 1 is set to maintain a necessary and sufficient strength at the time of non-collision by preventing the inner portion 11 from being destroyed when the load at the time of collision is small and the generated stress is less than a predetermined value.

  In the torque rod 1, the rod portion 5 and the cylindrical portions 6 and 7 are integrally formed of a metal such as an aluminum alloy or an appropriate resin. In the case of a resin, a known material such as 6-6 nylon can be used, and fiber reinforcement can be performed if necessary. With either metal or resin, a long extruded material is formed by extruding the front view shape in FIG. 3 as a cross-sectional shape, and then the extruded material is cut at a predetermined thickness interval perpendicular to the extrusion direction. Can be formed efficiently. In particular, since the central axes C1 and C2 of the cylindrical portions 6 and 7 are parallel to the lateral direction and coincide with the penetration direction of the end hole 10 and each of the hollows 8, the entire extrusion is integrally extruded. Is possible.

  In addition, there is no weld joint between the rod portion 5 and the cylindrical portions 6 and 7 by integrally forming the whole. Since stress concentration is likely to occur in such a welded joint, the fracture site tends to become unstable or the fracture load tends to be difficult to control. However, the absence of such a welded joint makes it possible to specify the fracture site and control the fracture load.

  Next, the operation of this embodiment will be described. 4 and 5 show the operation of the cylindrical portion 6 at the time of collision. In FIG. 1, when the power unit 3 moves rearward due to a collision, the rod portion 5 is compressed in the direction of the action axis C. Then, as shown in A of FIG. 4, the compression load F <b> 1 at the time of the collision is input to the point P of the inner portion 11 through the bush 2.

  The stress due to the compressive load F1 at the time of the collision is concentrated on the maximum stress portion R. However, the behavior is different at points P and Q in the maximum stress portion R, and the outer point Q receives a tensile stress f2 and the inner point P receives a compressive stress f1. Therefore, when the tensile strain due to the tensile stress f2 in the maximum stress portion R becomes larger than the limit strength of the portion of the maximum stress portion R adjusted by the weak portion 12, the weak portion 12 is the starting point as shown in FIG. It is destroyed by cracking.

  Accordingly, the fragile portion 12 is surely broken, and the rupture position is specified by the fragile portion 12 and becomes constant. In addition, the fracture load that is a load (in this case, corresponding to the compressive load F1) at the time of causing the fracture starting from the fragile portion 12 at the maximum stress portion R is also constant. In addition, since this fracture uses the tensile stress accompanying the input of the compressive load F1, it can be reliably destroyed even by the compressive load.

  In addition, when a predetermined compressive load F1 is input, the predetermined weak portion 12 of the cylindrical portion 6 is always broken, so that the break position is accurate and the control of the break load is also accurate. In addition, since it is not necessary to provide a special structure on the vehicle body or the power unit side by breaking with the cylindrical portion 6 instead of the rod portion 5 which is not easily broken against the compressive load, the breaking structure at the time of collision with the torque rod 1 alone is not required. The structure for destruction is simplified.

  Further, if the tensile strain for causing the fracture in the fragile portion 12 is related to the predetermined compressive load F1 at the time of the collision, the predetermined compressive load F1 is input at the time of the collision so that the fragile portion 12 can reliably Will cause destruction. Moreover, this association can be easily made by calculation or experiment. For this reason, it is possible to accurately specify the fracture position and to accurately control the value of the compression load corresponding to the compression load F1 at the time of collision that causes the fracture.

 As a result, even when the torque rod 1 is made of an aluminum alloy or the like and has a high overall rigidity, it is easy to specify the fracture position, which is effective in controlling the fracture position for such a high-rigidity member. is there.

  Further, when the inner portion 11 is broken as shown in FIG. 4B at the time of a collision, the bush 2 passes through the broken portion and exits from the bush hole 16 and enters the end hole 10 as shown in FIG. The figure shows the movement trajectory of the inner cylinder 17 at this time, and the inner cylinder 17 serves as an input portion for a compression load. The inner cylinder 17 is shown to represent the movement trajectory of the bush 2.

  When the inner cylinder 17 (bush 2) reaches the guide portion 13, the guide portion 13 obliquely intersects with the action axis C, and in this figure, the guide portion 13 is inclined obliquely upward to the rear, so that it contacts the guide portion 13. As a result, the inner cylinder 17 (bush 2) is guided obliquely upward in the drawing, guided outward in the direction perpendicular to the action axis C, and finally detached from the rod portion 5.

  For this reason, even if the inner side part 11 is destroyed, it is possible to avoid a situation in which the bush 2 remains inside the rod part 5 and continues to exert a compressive load F1 upon collision on the rod part 5. As a result, it is possible to reliably block transmission of the predetermined compressive load F1 at the time of collision to the rod portion 5 side.

  On the contrary, the fragile portion 15 on the cylindrical portion 7 side is to be broken by a load input in the pulling direction at the time of collision. In FIG. 3, when the tensile load F2 at the time of collision is input, the entire torque rod 1 is pulled forward. At this time, tensile strain does not occur in the fragile portion 12, but tensile strain occurs in the fragile portion 15 instead.

  That is, since the bush 2 pushes the cylindrical portion 7 backward, the tensile strain similar to that described with reference to FIG. 4A is generated on the fragile portion 15 provided on the outer peripheral side of the outer portion 16 of the cylindrical portion 7. . Moreover, since the fragile portion 15 is on the action axis C in the outer portion 16 of the cylindrical portion 7 and is located at the maximum stress portion, the cylindrical portion 7 is also caused by the tensile strain generated with the input of the predetermined tensile load F2. The fragile portion 15 is destroyed starting from the destruction start point. Similar to the fragile portion 12, the fracture position and the tensile load F2 can be accurately controlled.

In this example, since the fragile portions 12 and 15 are provided in the cylindrical portions 6 and 7, respectively, it is possible to accurately destroy any load input at the time of collision in the compression direction and the pulling direction. Further, the rod portion 5 can be broken at both end sides.
Furthermore, the magnitude of the tensile strain that causes breakage in the fragile portions 12 and 15 can be set to be different, and even in this case, the different compression load F1 or tensile load F2 can be accurately controlled.

  The present invention is not limited to the above-described embodiments, and various modifications and applications can be made within the principle of the invention. For example, the weak portion 12 and the same portion 15 can be provided only on one side. Alternatively, only one of the cylindrical portions 6 or 7 may be provided, and the other side may be a yoke having a substantially U-shaped bifurcated structure. In this case, either the fragile portion 12 or 15 will be provided. If the fragile portion 12 is used, the torque rod will be broken by a load input at the time of a collision in the compression direction. It becomes a torque rod of the type that breaks by the load input at the time of collision.

Furthermore, the fragile portions 12 and 15 are not limited to recesses, and may be through holes or thin portions. In this case, the thin portion is formed by reducing the thickness in the direction of the central axis C1 or C2 that is the width direction. The through hole penetrates in the same direction and can be easily formed at the time of the extrusion molding. Further, the rod portion 5 and the cylindrical portions 6 and 7 may be separately manufactured by casting, forging, or the like, and may be coupled to each other by welding or the like.

Schematic diagram showing torque rod usage Torque rod perspective view Front view of torque rod Action diagram Same as above

Explanation of symbols

1: Torque rod, 2: Bush, 3: Power unit, 4: Vehicle body, 5: Rod part, 6: Cylindrical part, 7: Cylindrical part, 8: Vent hole, 9: Bulkhead, 12: Fragile part, 15: Fragile Part

Claims (5)

In a torque rod comprising a rod portion and bush mounting brackets provided at both ends thereof, and connected to the power unit and the vehicle body via bushes supported by these bush mounting brackets,
At least one side of the bracket for mounting the bush is a cylindrical portion, and the outer peripheral portion of the cylindrical portion is a portion overlapping with the action axis line connecting the load input points of both the brackets for mounting the bush. A torque rod characterized in that a weak portion is provided at a site where the rupture occurs and the cylindrical portion is broken starting from the weak portion when a predetermined load is input.   2. The torque according to claim 1, wherein the fragile portion is a concave portion provided on an arcuate curved surface on an outer periphery of the cylindrical portion, or a through hole or a thin portion formed toward a central axis direction of the cylindrical portion. rod.   2. The torque rod according to claim 1, wherein the fragile portion is provided on the rod portion side of the cylindrical portion, and is broken by a predetermined load at the time of a collision input to the rod portion in a compression direction. .   2. A guide portion obliquely intersecting with the axial direction of the rod portion is provided, and an input portion of a compressive load that moves when the fragile portion is broken is separated from the rod portion to the outside of the working axis. The torque rod described in any one of?   2. The torque according to claim 1, wherein the fragile portion is provided on a side opposite to the rod portion of the cylindrical portion, and is destroyed by a predetermined load at the time of a collision input to the rod portion in a pulling direction. rod.

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