JP6535617B2 - Stabilizer for vehicle and jig for shot peening for the stabilizer - Google Patents

Description

  The present invention relates to a stabilizer for a vehicle disposed in a suspension mechanism of a vehicle such as an automobile, and a jig for shot peening for the stabilizer.

  The stabilizer disposed in the suspension mechanism of the vehicle is a steel pipe or a solid rod-like steel material, and a pair of a torsion portion (twist portion) extending in the width direction of the vehicle and a pair of bending portions at both ends of the torsion portion. It has an arm portion (arm portion) and a curved portion formed between the torsion portion and the arm portion. An eyeball is formed at the tip of each arm. In one example of the suspension mechanism, the torsion portion of the stabilizer is supported by the vehicle body via a rubber bush or the like, and the eyeball is connected to the suspension arm or the like of the suspension mechanism via a connecting member such as a stabilizer link. The stabilizer assembled to the suspension mechanism can enhance the roll rigidity of the vehicle by the arm, the bending portion and the torsion portion functioning as a spring with respect to the rolling behavior of the vehicle body.

  In the stabilizer, the force of bending in the opposite direction is applied to each of the arm portions by the one arm portion and the other arm portion moving in the opposite direction according to the traveling condition such as when the vehicle travels a curve. At the same time, bending and twisting forces are applied to the curved portion, and the torsion portion is twisted, thereby suppressing the rolling behavior of the vehicle body. Stress due to bending or twist is generated in the arm portion, the bending portion and the torsion portion. In particular, it is also known that stress peaks occur at curved portions.

  As a means for enhancing the fatigue strength of the stabilizer, for example, as disclosed in Patent Document 1, a shot peening apparatus is proposed in which fine particles (shots) such as a cut wire are projected onto the surface of the stabilizer by a projector. In order to enhance the durability of the stabilizer, it is also proposed to perform shot peening particularly carefully on the curved portion. However, in the radial cross section of the curved portion, the stress distribution is not constant in the circumferential direction. That is, a stress peak exists at a specific position in the circumferential direction.

  During travel of the vehicle, the bending portion is twisted in the first direction and the second direction with equal frequency. Therefore, in the radial cross section of the curved portion, assuming that the center of the bending inner side is 0 ° and the center of the bending outer side is 180 °, the stress distribution of the curved portion is symmetrical with respect to the reference line connecting 0 ° and 180 °. Become. Therefore, according to general knowledge, the shot should be projected evenly over the entire surface of the curved portion, or the distribution of compressive residual stress is symmetrical with the reference line connecting 0 ° and 180 ° as the axis of symmetry. It is customary for shot peening to

JP, 2010-228020, A

  However, as a result of intensive studies by the present inventors, depending on the aspect of the suspension mechanism in which the stabilizer is disposed, it may not always be the best if the stress distribution of the curved portion is symmetrical with respect to the reference axis. Findings were obtained. For example, the lower surface of the stabilizer may be affected by stepping stones or a snow melting agent to cause minute corrosion pits. For this reason, if the depth of compressive residual stress near the lower surface of the stabilizer is equal to that near the upper surface, the pit depth exceeds the depth of compressive residual stress when pits formed on the lower surface of the stabilizer grow to a certain extent , May affect the structural integrity of the stabilizer.

  Further, as in the shot peening apparatus described in Patent Document 1, when shot peening is performed one by one, the working efficiency is poor, and there is also a problem that the shot peening apparatus can not be used efficiently.

  Therefore, an object of the present invention is to provide a vehicle stabilizer having a preferable stress distribution with respect to durability of a curved portion, and a shot peening jig capable of efficiently performing shot peening on a plurality of stabilizers.

  The stabilizer according to one embodiment is formed of a rod-like steel material and extends in the width direction of the vehicle, a pair of curved parts connected to both ends of the torsion part, and a pair of arm parts connected to the respective curved parts. The curved portion has a radial cross section with respect to its circumferential position, and the center of the bending inner side is 0 °, the center of the bending outer side is 180 °, and the midpoint between 0 ° and 180 ° is When the opposite side of 90 ° and 90 ° is 270 °, the curved inner portion located at the 0 ° and having a compressive residual stress from the surface of the steel material to the first depth, and the surface located at the 180 ° and the surface A curved outer portion having compressive residual stress from the surface to the second depth, a first side surface portion having compressive residual stress from the surface to the third depth, located at the 90 °, and positioned at the 270 ° Compressive residual stress from the surface to the fourth depth And a second side surface portion, and the sum of compressive residual stress from the surface of the curved inner portion to the first depth is the amount of compressive residual stress from the surface of the curved outer portion to the second depth. The sum of compressive residual stress greater than the sum and from the surface of the second side surface to the fourth depth is the sum of compressive residual stress from the surface of the first side surface to the third depth It is characterized by being larger than. The first depth is deeper than the second depth. Also the fourth depth. Deeper than the third depth. In an example of the stabilizer, the steel material is a steel pipe, and the thickness of the curved outer side portion is smaller than the thickness of the curved inner side portion. The first side surface may be disposed on the upper side of the vehicle, and the second side surface may be disposed on the lower side of the vehicle.

  The shot peening jig according to one embodiment is the same as the center rod extending in the vertical direction, the upper arms radially provided at the upper portion of the center rod, and the upper arm at the lower portion of the center rod. The lower arms are provided radially as many as the number. The upper arm portions respectively support eyeballs formed on one arm portion of the stabilizer to hold the torsion portion of the stabilizer in a substantially vertical posture along the center rod. The lower arm supports the other arm of the stabilizer. In the shot peening jig, the curved inner portion and the second side surface portion of each stabilizer face the outside of the center rod in a state where the plurality of stabilizers are suspended by the upper arm portion, The curved outer side portion and the first side portion face inward. The tip of the upper arm may be provided with a pin inserted into the hole of the eyeball of the one arm. In addition, the lower end of the lower arm may have a hook for supporting the other arm.

  ADVANTAGE OF THE INVENTION According to this invention, in order to improve durability of a curved part, the stabilizer which has distribution of a compressive residual stress preferable can be obtained, and durability of a stabilizer can be improved.

The perspective view which shows a part of vehicle and a stabilizer. The top view which shows an example of a stabilizer. FIG. 3 is a radial cross-sectional view of a curved portion of the stabilizer, taken along line F3-F3 in FIG. 2; BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows stabilizer (s) and the jig | tool for shot peening which concern on one Embodiment. The top view which looked at the stabilizer and jig for shot peening shown in Drawing 4 from the upper part. The top view which looked at only stabilizer (s) shown by FIG. 4 from upper direction. The top view which looked at only the jig for shot peening shown in Drawing 4 from the upper part. The side view which shows a stabilizer and a shot peening apparatus typically. The graph showing the relationship of the depth from the surface, and the magnitude | size of a residual stress about four places of the circumferential direction of the 1st curved part of the stabilizer of one embodiment. The graph showing the relationship of the depth from the surface, and the magnitude | size of a residual stress about four places of the circumferential direction of the 2nd curved part of the stabilizer.

Hereinafter, a stabilizer according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 shows a part of a vehicle 11 provided with a stabilizer 10. FIG. 2 is a plan view of the stabilizer 10. The stabilizer 10 is disposed in the suspension mechanism of the vehicle 11. Stabilizer 10 includes a torsion portion 20 extending in the width direction (direction indicated by arrow W in FIG. 1) of vehicle body 12 of vehicle 11, a pair of curved portions 21 and 22 connected to both ends of torsion portion 20, and respective curved portions 21. , 22 and is formed by a bending machine. The material of the stabilizer 10 is a rod-like spring steel of a steel type whose strength can be improved by heat treatment such as quenching. Since this embodiment is a hollow stabilizer 10, a hollow steel (steel pipe) 10A is used. In the case of a solid stabilizer, solid steel is used.

  The stabilizer 10 is symmetrical about the symmetry axis S1 (shown in FIG. 2) and has eyeballs 25 and 26 at both ends. However, the shape of the stabilizer 10 is not limited to FIG. 2, and the torsion portion 20 and the arm portions 23 and 24 may have one or more bent portions. The shapes of the eyeballs 25 and 26 also vary depending on the aspect of the suspension mechanism. That is, stabilizers of various shapes may be used, including a three-dimensional bending shape.

  The torsion portion 20 is supported by, for example, a part of the vehicle body 12 via a pair of support portions 30 and 31 provided with a rubber bush or the like. The pair of eyeballs 25 and 26 are connected to, for example, a suspension arm (not shown) of the suspension mechanism via connecting members 32 and 33 such as stabilizer links. When loads in opposite phases (upward or downward) are input to the arm portions 23 and 24 when the traveling vehicle 11 bends, bending forces in opposite directions are applied to the arm portions 23 and 24 and the bending portion 21 , 22 is subjected to bending and twisting forces, and the torsion portion 20 is further twisted. Thus, a repulsive load for suppressing the rolling behavior of the vehicle body 12 is generated.

Since the bending portions 21 and 22 are symmetrical with respect to the symmetry axis S1 (shown in FIG. 2), the first bending portion 21 (FIG. 3) will be representatively described hereinafter. The second curved portion 22 also has the same configuration.
FIG. 3 shows a radial cross section of the bending portion 21. As shown in FIG. In this specification, with respect to the circumferential position of the radial cross section of the bending portion 21, the center of the inside of the bend is 0 °, the center of the outside of the bend is 180 °, and the middle between 0 ° and 180 ° The point is defined as 90 ° and the opposite side of 90 ° as 270 °. A line segment X1 connecting 0 ° and 180 ° is called a reference line, and a line segment Y1 (line segment connecting 90 ° and 270 °) perpendicular to the line segment X1 is called a perpendicular.

  That is, with respect to the position in the circumferential direction in the radial cross section, this curved portion 21 is a curved inner portion located at 0 ° when the center of the bending inner side of the curved portion 21 is 0 ° and the center of the bending outer side is 180 °. 41, a curved outer portion 42 located at 180 °, a first side 51 located at 90 °, and a second side 52 located at 270 °.

  Since the stabilizer 10 bends the steel pipe by a bending machine, the thickness t2 of the curved outer portion 42 is smaller than the thickness t1 of the curved inner portion 41 in the radial cross section of the curved portion 21. Moreover, the range of 90 ° to 270 ° has a somewhat flat cross-sectional shape. The dashed-two dotted line Q1 in FIG. 3 has shown the outline of the outer surface (substantially perfect circle) of the steel pipe before a bending process.

The shot peening jig 60 will be described below with reference to FIGS. 4 to 8.
FIG. 4 shows a shot peening jig 60 and a plurality of (for example, six) stabilizers 10 held by the shot peening jig 60. 5 is a plan view of the shot peening jig 60 and the stabilizer 10 viewed from above, FIG. 6 is a plan view of only the stabilizer 10 viewed from above, and FIG. 7 is a view of only the shot peening jig 60 from above It is a plan view.

  The shot peening jig 60 includes a center rod 61 extending in the vertical direction, a plurality of (for example, six) upper arm portions 62 provided on the upper portion of the center rod 61, and a plurality of For example, six lower arms 63 are provided. The upper arm portion 62 is fixed to the center rod 61 via the upper mounting base 65. The lower arm 63 is fixed to the center rod 61 via the lower mounting base 66.

  The upper arms 62 are provided in a number corresponding to the number (for example, six) of the stabilizers 10 to be supported at one time by the shot peening jig 60. The upper arm portions 62 have a shape common to each other, and are radially provided at equal intervals in the circumferential direction of the mounting base 65 from the center rod 61 toward the outside. At the tip of each upper arm 62, a pin 70 to be inserted into the hole 25a of one eye 25 of the stabilizer 10 is provided. The pin 70 projects upward from the tip of the upper arm 62.

  The lower arms 63 are provided in the same number (for example, six) as the upper arms 62. The lower arms 63 have a shape common to each other, and are radially provided at equal intervals in the circumferential direction of the mounting base 66 from the center rod 61 toward the outside. At the tip of each lower arm 63, a hook 71 having a shape (for example, a U shape) capable of holding the arm 24 positioned on the lower side in FIG.

  The eyeball 25 of one arm 23 of the stabilizer 10 is supported by the pin 70 of the upper arm 62, and the stabilizer 10 is suspended by its own weight, and the other arm 24 is held by the hook 71 of the lower arm 63. Ru. In this state, the stabilizer 10 is in a vertical posture in which the torsion portion 20 follows the center rod 61. The plurality of stabilizers 10 are simultaneously suspended by the shot peening jig 60 at equally spaced angles θ1 (shown in FIGS. 5 and 6) in the circumferential direction. An example of the angle θ1 is 60 °. The shot is projected from the direction indicated by the arrow SP in FIG.

  As shown in FIGS. 5 and 6, in the stabilizer 10 suspended by the shot peening jig 60, the curved inner portion 41 and the second side surface portion 52 face outward, and the curved outer portion 42 and the first And the side 51 of the face face inward. That is, according to the type of the stabilizer 10, the angle θ2 (shown in FIG. 7) between the upper arm 62 and the lower arm 63 so that the curved inner portion 41 and the second side surface 52 face outward. The shapes and lengths of the upper arm 62 and the lower arm 63, the position of the pin 70, the shape of the hook 71, and the like are set.

  FIG. 8 schematically shows a shot peening apparatus 80 for performing shot peening on a plurality of (for example, six) stabilizers 10 held by a shot peening jig 60. The shot peening apparatus 80 rotates a first shot projector 81 disposed on the lower side, a second shot projector 82 disposed on the upper side, and a jig 60 for shot peening around the center rod 61. And a rotating mechanism 83. For example, in a state where six stabilizers 10 are simultaneously held by the shot peening jig 60, the shot peening jig 60 and the stabilizer 10 rotate integrally in the direction indicated by the arrow Z.

  The first shot projector 81 projects a shot toward the first bending portion 21 as schematically shown by a two-dot chain line P1 in FIG. The shot projected from the first shot projector 81 collides with the upper half portion or the like of the stabilizer 10 on the side closer to the first shot projector 81 (right side in FIG. 8), whereby Compressive residual stress occurs on the surface of the upper half. The shot projected from the first shot projector 81 also collides with the stabilizer 10 on the far side (left side in FIG. 8) from the first shot projector 81, whereby the upper half portion of the stabilizer 10 on the far side is Compressive residual stress also occurs on the surface.

  The second shot projector 82 projects a shot toward the second bending portion 22, as schematically shown by a two-dot chain line P2 in FIG. The shot projected from the second shot projector 82 collides with the lower half portion or the like of the stabilizer 10 on the side closer to the second shot projector 82 (right side in FIG. 8), etc. Compressive residual stress occurs on the surface of the lower half. The shot projected from the second shot projector 82 also collides with the stabilizer 10 on the side far from the second shot projector 82 (the left side in FIG. 8). Compressive residual stress also occurs on the surface.

  In the stabilizer 10 held by the shot peening jig 60, as shown in FIG. 6, the curved inner portion 41 and the second side portion 52 face outward, and the curved outer portion 42 and the first side portion 51 and turn to the inside. For this reason, the shot projected from the first shot projector 81 and the second shot projector 82 is particularly effectively hit to the curved inner portion 41 and the second side surface 52.

  FIG. 9 shows the depth from the surface and the magnitude of the residual stress at four positions (0 °, 90 °, 180 °, 270 °) in the circumferential direction of the first curved portion 21 after shot peening. It shows the relationship. The solid line L1 in FIG. 9 indicates the distribution of residual stress in the curved inner portion 41 (0 °). An alternate long and short dash line L2 indicates the distribution of residual stress in the curved outer portion 42 (180 °). The broken line L3 shows the distribution of residual stress of the first side surface 51 (90 °). A two-dot chain line L4 indicates the distribution of residual stress of the second side surface 52 (270 °).

  As shown in FIG. 9, the curved inner portion 41 (0 °) has a compressive residual stress formed from the surface to the first depth D1. The curved outer portion 42 (180 °) has a compressive residual stress formed to a second depth D2. The first depth D1 is deeper than the second depth D2. In the first side surface portion 51 (90 °), compressive residual stress is formed up to the third depth D3. The second side surface portion 52 (270 °) has a compressive residual stress formed up to a fourth depth D4. The fourth depth D4 is deeper than the third depth D3.

  As shown in FIG. 9, the absolute value of the compressive residual stress of the curved inner portion 41 (0 °) is higher than the absolute value of the compressive residual stress of the curved outer portion 42 (180 °) in the region deeper than 0.15 mm. large. Moreover, the sum (area) of the compressive residual stress from the surface of the curved inner portion 41 (0 °) to the first depth D1 is the compression from the surface of the curved outer portion 42 (180 °) to the second depth D2 Larger than the total sum (area) of residual stress. The absolute value of the compressive residual stress of the second side surface 52 (270 °) is larger than that of the first side surface 51 (90 °) at any depth. Moreover, the sum (area) of the compressive residual stress from the surface of the second side surface 52 (270 °) to the fourth depth D4 is the third depth from the surface of the first side surface 51 (90 °) Greater than the sum (area) of compressive residual stress up to D3.

  FIG. 10 shows the depth from the surface and the magnitude of the residual stress at four circumferential positions (0 °, 90 °, 180 °, 270 °) of the second curved portion 22 after shot peening. It shows the relationship. The solid line R1 in FIG. 10 indicates the distribution of residual stress at the curved inner portion 41 (0 °). An alternate long and short dash line R2 indicates the distribution of residual stress in the curved outer portion 42 (180 °). The broken line R3 shows the distribution of residual stress of the first side surface 51 (90 °). And, a two-dot chain line R4 shows the distribution of the residual stress of the second side surface 52 (270 °).

  As shown in FIG. 10, in the curved inner portion 41 (0 °), compressive residual stress is formed from the surface to a first depth d1. The curved outer portion 42 (180 °) has a compressive residual stress formed to a second depth d2. The first depth d1 is deeper than the second depth d2. The first side surface portion 51 (90 °) has a compressive residual stress formed to a third depth d3. The second side surface portion 52 (270 °) has a compressive residual stress formed up to the fourth depth d4. The fourth depth d4 is deeper than the third depth d3.

  As shown in FIG. 10, the absolute value of the compressive residual stress of the curved inner portion 41 (0 °) is higher than the absolute value of the compressive residual stress of the curved outer portion 42 (180 °) in the region deeper than 0.10 mm. large. Moreover, the sum (area) of the compressive residual stress from the surface of the curved inner portion 41 (0 °) to the first depth d1 is the compression from the surface of the curved outer portion 42 (180 °) to the second depth d2 Larger than the total sum (area) of residual stress. The absolute value of the compressive residual stress of the second side surface 52 (270 °) is greater than the absolute value of the compressive residual stress of the first side surface 51 (90 °) at any depth. Moreover, the sum (area) of the compressive residual stress from the surface of the second side surface 52 (270 °) to the fourth depth d4 is the third depth from the surface of the first side surface 51 (90 °) Greater than the sum (area) of compressive residual stress up to d3.

  That is, in either case of FIG. 9 and FIG. 10, the sum (area) of the compressive residual stress in the curved inner portion 41 (0 °) is larger than the sum (area) of the compressive residual stress in the curved outer portion 42 (180 °) And, the sum (area) of the compressive residual stress of the second side face 52 (270 °) is larger than the sum (area) of the compressive residual stress of the first side face 51 (90 °).

  Thus, in the stabilizer 10 of the present embodiment, compressive residual stress is formed to a position deeper than the curved outer portion 42 in both the first curved portion 21 and the second curved portion 22. In addition, the sum (area) of the compressive residual stress of the curved inner portion 41 is larger than the sum (area) of the compressive residual stress of the curved outer portion 42. For this reason, it becomes distribution of effective compressive stress to a peak of stress which may arise in curved inner side part 41, and it can avoid that curved inner side part 41 becomes a weak point about endurance.

  Moreover, in each of the first curved portion 21 and the second curved portion 22, compressive residual stress is formed to a position deeper than the first side surface 51 in the second side surface 52, and the second side surface 52 is formed. The sum (area) of the compressive residual stress is larger than the sum (area) of the compressive residual stress of the compressive residual stress of the first side surface portion 51. For this reason, for example, even if a corrosion pit is generated on the second side portion 52 which has a high possibility of coming into contact with a bouncer and a road surface freezing agent during traveling, a distribution of compressive residual stress effective to suppress the influence is obtained. . However, depending on the aspect of the suspension mechanism or the specification of the stabilizer, the stabilizer may be disposed such that the second side surface 52 is on the upper side.

  In the practice of the present invention, the distribution of compressive residual stress may be appropriately changed without departing from the scope of the present invention according to the mode of the suspension mechanism or the specification of the stabilizer. It goes without saying that various modifications can be made to the embodiment such as the material of the stabilizer, and the specific shapes of the torsion portion, the arm portion and the curved portion, and the arrangement of the stabilizer.

  DESCRIPTION OF SYMBOLS 10 Stabilizer 11 Vehicle 20 Torsion part 21,22 Curved part 23,24 Arm part 25,26 Eye ball part 25a Hole 41 inside curved part 42 Outside curved part DESCRIPTION OF SYMBOLS 51 ... 1st side part, 52 ... 2nd side part, 60 ... Jig for shot peening, 61 ... Center rod, 62 ... Upper arm, 63 ... Lower arm, 70 ... pin, 71 ... Hook part .

Claims (7)

A torsion member made of a rod-like steel material and extending in the width direction of the vehicle;
A pair of curved portions connected to both ends of the torsion portion;
And a pair of arm portions connected to the respective curved portions,
Each of the curved portions has a radial cross section with respect to a circumferential position thereof,
When the center of bending inside is 0 °, the center of bending outside is 180 °, the midpoint between 0 ° and 180 ° is 90 °, and the opposite side of 90 ° is 270 °,
A curved inner portion located at the 0 ° and having a compressive residual stress from the surface of the steel material to a first depth;
A curved outer portion located at the 180 ° and having a compressive residual stress from the surface to a second depth;
A first side portion located at the 90 ° and having a compressive residual stress from the surface to a third depth;
And a second side portion located at the 270 ° and having a compressive residual stress from the surface to a fourth depth, and
The sum of compressive residual stress from the surface of the curved inner portion to the first depth is larger than the sum of compressive residual stress from the surface of the curved outer portion to the second depth,
The sum of the compressive residual stress from the surface of the second side surface part to the fourth depth is larger than the sum of the compressive residual stress from the surface of the first side surface part to the third depth Stabilizer for vehicles.   The vehicle stabilizer according to claim 1, wherein the first depth is deeper than the second depth, and the fourth depth is deeper than the third depth.   The stabilizer for a vehicle according to claim 1 or 2, wherein the steel material is a steel pipe, and a thickness of the curved outer side portion is smaller than a thickness of the curved inner side portion.   The vehicle stabilizer according to claim 1 or 2, wherein the first side surface portion is disposed on the upper side of the vehicle, and the second side surface portion is disposed on the lower side of the vehicle. Torsion parts made of rod-like steel material extending in the width direction of the vehicle, a pair of curved parts connected to both ends of the torsion part, a pair of arm parts connected to the respective curved parts, and a tip formed of each arm part A jig for shot peening for a stabilizer having an eyeball portion,
The stabilizer is located at a circumferential cross-section of each of the curved portions in the radial direction, and the center of the curved inner side of each curved portion is 0 °, and the center of the curved outer side is between 180 ° and 0 ° 90 ° and the opposite side of the 90 ° are 270 °, the curved inner portion located at the 0 °, the curved outer portion located at the 180 °, and the first side surface located at the 90 ° And a second side portion located at the 270.degree.
The shot peening jig is
A vertically extending center rod,
And an upper arm portion provided radially on the upper portion of the center rod, and supporting the eyeball portion formed on one of the arm portions of the stabilizer to hold the torsion portion along the center rod. ,
And a lower arm portion provided radially at the lower portion of the center rod by the same number as the upper arm portion and supporting the other arm portion of the stabilizer,
In the state where the stabilizer is suspended, the curved inner side portion and the second side surface portion of each stabilizer face the outer side of the center rod, and the curved outer side portion and the first side surface portion face the inner side. Jig for shot peening of the stabilizer characterized by the above.   The shot peening jig according to claim 5, further comprising: a pin inserted into a hole of an eyeball portion of the one arm portion at a tip end of the upper arm portion.   7. The shot peening jig according to claim 5, wherein a hook portion for supporting the other arm portion is provided at a tip end of the lower arm portion.

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