JP2005306146A - Designing method for steering knuckle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a designing method for a steering knuckle capable of reducing the squeaking of a brake easily. <P>SOLUTION: The fundamental designing of the steering knuckle 10 is executed, and the vibrating characteristics of a calipers mount 14 to be connected are acquired, followed by formation of a stationary body 18 with a calipers mount 14 secured to the steering knuckle 10, and simulation is made for the vibrating characteristics of the whole stationary body 18 when the calipers mount 14 is vibrated on the basis of its vibrating characteristics of the mount 14. A shape change of the steering knuckle 10 is executed so as to suppress the peak value of the vibrating characteristics of the stationary body 18 on the basis of the result from simulation, and the steering knuckle 10 is allowed to function as a dynamic damper with respect to the calipers mount 14. The stationary body 18 is dropped into the desired vibrating characteristics until the brake squeak reduces by performing the simulation of the vibrating characteristics of the stationary body with the shape changed and another shape change repetitively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steering knuckle design method, and more particularly to an improvement in a steering knuckle design method capable of suppressing the squealing of a brake in the caliper mount when the caliper mount is connected.

  Conventionally, a disc brake used as a braking device for a vehicle includes a disc rotor that rotates together with an axle and a caliper that supports a pad that presses against the disc rotor. This caliper is fixed to the steering knuckle as a caliper mount. The steering knuckle is also formed with a portion for receiving an axle, a lower arm, a shock absorber, a tie rod, and the like.

By the way, when the vehicle brakes, the pad is pressed against the disc rotor by hydraulic pressure. At this time, the caliper vibrates depending on the state of the pad, the state of the disc rotor, etc., and an abnormal noise, that is, “brake squeal” is generated. Since this brake squeak gives the driver a sense of incongruity and discomfort, various measures have been conventionally taken to suppress the brake squeal. For example, it is conceivable to suppress vibrations by changing the shape of the caliper mount that supports the caliper or adding mass. Further, for example, a configuration has been proposed in which brake squeal is reduced by improving the torsional rigidity of the steering knuckle-side mounting portion that supports the caliper mount. Specifically, by providing a reinforcement connecting portion that directly connects a plurality of attachment portions on the steering knuckle side, the rigidity on the steering knuckle side is improved, and vibration suppression on the caliper mount side is attempted (for example, , See Patent Document 1).
JP 2002-161930 A

  However, when trying to suppress brake noise by changing the shape of the caliper mount or attaching an additional component, it is necessary to ensure a large rigidity. That is, a large shape change of the caliper mount and attachment of a large appendage accompany the increase in size of each member. Normally, there is little space around the steering knuckle, and the above-described vibration suppression by changing the shape of the caliper mount or attaching an additional object is not preferable. Similarly, it is not preferable in terms of space to add a reinforcing connecting member to the steering knuckle. Furthermore, such a shape change or attachment of additional members places many restrictions on the design of caliper mounts and steering knuckles, and causes a reduction in design flexibility.

  Accordingly, an object of the present invention is to provide a steering knuckle design method capable of reducing brake noise without changing the shape of the caliper mount and without changing the shape of the steering knuckle. And

  The present invention includes a step of performing a basic design of a steering knuckle, a step of obtaining vibration characteristics of a caliper mount connected to the steering knuckle, a fixed body in which the caliper mount is fixed to the steering knuckle, and forming a caliper mount. The step of simulating the vibration characteristics of the whole fixed body when vibrated based on the vibration characteristics, and the shape change of the steering knuckle to suppress the peak value of the vibration characteristics based on the vibration characteristics of the fixed body A step of causing the steering knuckle to function as a dynamic damper with respect to the caliper mount, and a step of repeatedly simulating and changing the vibration characteristics of the fixed body after the shape change, and dropping the fixed body into a desired vibration characteristic. To do.

  Here, the caliper mount includes a caliper main body and a mount main body. Further, the basic design of the steering knuckle is a design of the shape, strength, weight, etc. of the steering knuckle required for a predetermined vehicle according to each design condition.

  According to this configuration, the steering knuckle is actively vibrated by changing the shape only on the steering knuckle side. That is, the vibration characteristic on the steering knuckle side is substantially matched with the vibration characteristic on the integrated caliper mount side, and the steering knuckle functions as a dynamic damper for the caliper mount. As a result, the fixed body composed of the steering knuckle and the caliper mount vibrates integrally, suppressing the vibration of the caliper mount alone and reducing the brake squeal.

  Further, in the above configuration, the shape change of the steering knuckle is performed by overlaying or shaving.

  According to this configuration, the vibration characteristics can be adjusted by slightly building up or shaving using the entire steering knuckle.

  In the above configuration, the steering knuckle changes the vibration state of the protrusion of the steering knuckle by the build-up or the shaving.

  Usually, the steering knuckle is formed with a projection for connecting, for example, a shock absorber. For example, by performing build-up or shaving of the root portion of the protrusion, the vibration state of the protrusion can be greatly changed by a slight change in shape, and the vibration characteristics can be adjusted efficiently.

  According to the present invention, the steering knuckle can be made to function as a dynamic damper with respect to the caliper mount, and the vibration of the caliper mount can be suppressed to reduce the brake squeal easily.

  Hereinafter, an embodiment of the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a caliper mount 14 including a steering knuckle 10 and a caliper 12 constituting a part of a disc brake of the present embodiment. FIG. 1 shows a conceptual shape of a steering knuckle 10 used for a strut suspension as an example. The steering knuckle 10 is a metal rigid body, and an opening 10a for receiving an axle is formed at substantially the center. A protrusion 10b for connecting a shock absorber is provided above the opening 10a, and a tie rod is connected to the right side in the figure. On the lower side, a protrusion 10d that connects the lower arm is formed, and on the left side, protrusions 10e and 10f that fix the caliper mount 14 including the caliper 12 are formed. A rubber bush, for example, is interposed between the shock absorber, tie rod, and lower arm and the projections 10b, 10c, and 10d, and the steering knuckle 10 is supported and fixed to each connection member in a free state. It is like that. On the other hand, the caliper mount 14 includes the caliper 12 and the mount main body 14a, and is firmly fixed to each other. Further, the mount main body 14a is firmly fixed to the steering knuckle 10 with no inclusions interposed therebetween.

  Inside the caliper 12, there are a cylinder and a piston, and a braking force is generated by pressing the pad against a disk rotor (not shown) that rotates together with the wheel by hydraulic pressure. During this braking operation, the pad vibrates and the caliper 12 further vibrates to generate a brake squeal. In general, the frequency of the brake squeal is 2 to 15 kHz, but differs depending on the shape and configuration of the caliper 12 and the steering knuckle 10 to which the caliper 12 is fixed. Therefore, depending on the configuration of the vehicle, there is a brake squeezing frequency band that tends to occur, and it is desirable to take measures to suppress the sound in this frequency band.

  In order to prevent the sound of a predetermined frequency band from being generated, it is conceivable to suppress the vibration of the sound generation source. However, as described above, in order to suppress the vibration, the vibration part (that is, the caliper mount 14). ) And the support portion of the vibrating body (that is, the steering knuckle 10), it is accompanied by an increase in the size and weight of the component. Is not preferred.

  Therefore, in the present embodiment, the steering knuckle 10 is intentionally changed by subjecting the steering knuckle 10 to build-up and shaving, and the steering knuckle 10 is vibrated positively. Is functioning as a dynamic damper. By causing the steering knuckle 10 to function as a dynamic damper, vibration of the caliper mount 14 is suppressed, and as a result, brake noise is reduced.

  In the case of the steering knuckle 10, as described above, a plurality of protrusions 10b to 10f are formed in order to connect various members. Since the protrusions 10b to 10f only need to be sufficiently connected to a predetermined member (such as a shock absorber), the shape has a large degree of freedom, and has a predetermined strength and size (a size that fits in a predetermined space). ). In addition, since each member is connected in a free state via a bush, even if the steering knuckle 10 is vibrated at a frequency of about 2 to 15 kHz at which a brake squeal occurs, the frequency is determined by the vehicle occupant. Since it is far away from the frequency of several tens to several hundreds of Hz that affects the ride comfort, it is hardly recognized as vibration.

  Therefore, in the present embodiment, as shown in FIG. 1, for example, overlaying or shaving (indicated by the hatching portion 16) is performed so as to vibrate the protrusion 10 b connecting the shock absorber positively. In general, the shaving may lead to a decrease in the strength of the steering knuckle 10. Therefore, it is desirable to deal with the basic shape of the steering knuckle 10 by building up.

  As shown in FIG. 1, for example, if the protrusion 10b begins to bend as a result of embedding the root of the protrusion 10b of the steering knuckle 10, for example, the protrusion 10d is bent by the reaction force, and the steering knuckle 10 is bent. The mode shifts and the entire steering knuckle 10 starts to vibrate. At this time, for example, the steering knuckle 10 is dynamically overlaid or shaved (changed in shape) so that the bending / twisting resonance of the steering knuckle 10 is the same as the torsional resonance frequency of the caliper mount 14. By functioning as a damper, it becomes possible to suppress the vibration of the caliper mount 14, and it is possible to reduce and prevent brake noise due to the vibration of the caliper mount 14.

  In addition, as described above, it is possible to greatly change the vibration state of the protrusion 10b or the like by a slight change in shape by performing the build-up or shaving of the root portion of the protrusion 10b or the like, and the vibration characteristics can be improved. Can be adjusted.

  Hereinafter, a specific method for designing the steering knuckle 10 will be described with reference to the flowchart of FIG. In the present embodiment, an example of computer aided engineering (CAE) will be described in which the design of the steering knuckle 10 is a 3D model on a computer.

  The designer first performs basic design of the steering knuckle 10 (S100). Here, the basic design of the steering knuckle 10 is to determine the shape, strength, weight, etc. of the steering knuckle 10 based on design conditions for mounting on a predetermined vehicle. Subsequently, data such as the shape of the caliper mount 14 (including the caliper 12) adapted to the steering knuckle 10 for which the basic design has been completed is acquired (S101), and the vibration characteristics thereof are acquired (S102). The caliper 12 has a different shape depending on the type of disc brake used. Therefore, the vibration characteristics of the caliper mount 14 including the caliper 12 are also different from each other. Therefore, the shape data, vibration characteristics, and the like of the caliper mount 14 including the caliper 12 may be read in advance by creating data or analyzing the vibration, or may be created and analyzed on the spot. For analysis of vibration, for example, an analysis method using a finite element method or the like can be used.

  Next, a fixed body 18 (see FIG. 1) in which the caliper mount 14 including the caliper 12 is fixed to the steering knuckle 10 for which basic design has been performed is formed on the 3D screen (S103). Subsequently, based on the vibration characteristic data of the caliper mount 14 acquired in step (S102), the caliper mount 14 constituting the fixed body 18 is vibrated to simulate the vibration characteristics of the fixed body 18 as a whole (S104). In this case, for example, a resonance waveform distribution as shown in FIG. In FIG. 3A, the brake squeal appears most noticeably at the frequency of the peak value P (S105).

  If the brake squeal exists (Y in S105), the shape of the steering knuckle 10 is changed in order to reduce the brake squeal by using the peak value of the frequency as a dynamic damper for the entire steering knuckle 10. Specifically, as shown in FIG. 1, a build-up (cutting as necessary) is performed around the protrusion 10b or the like (S106). Since the vibration state of the steering knuckle 10 changes depending on its shape, the process proceeds to step (S104), and the simulation of the vibration characteristics of the fixed body 18 after the shape change is performed again.

  If the torsional resonance frequency of the caliper mount 14 matches the torsional resonance frequency of the steering knuckle 10 due to the shape change of the steering knuckle 10, the caliper mount 14 and the steering knuckle 10 start to vibrate together. That is, the steering knuckle 10 starts to function as a dynamic damper with respect to the caliper mount 14, and the caliper mount 14 alone stops to suppress the brake noise. FIG. 3B shows a state in which the steering knuckle 10 functions as a dynamic damper, and as a result, the frequency at the peak value P decreases and the brake squeal at that frequency is suppressed. If the shape of the steering knuckle 10 is changed, the torsional resonance frequency of the caliper mount 14 and the torsional resonance frequency of the steering knuckle 10 do not coincide with each other, and a peak of a specific frequency exists, that is, the brake noise still remains. If it exists (Y in S105), step (S106) and the subsequent steps are repeated again.

  As described above, when brake squealing at a desired frequency is suppressed (N in S105), the shape of the steering knuckle 10 is determined (S107), and the design of the series of steering knuckles 10 is completed.

  By adopting such a design method of the steering knuckle 10, the steering knuckle 10 can function as a dynamic damper with respect to the caliper mount 14, and vibration of the caliper mount 14 can be suppressed to effectively and easily reduce brake noise. it can.

  In general, the frequency of the brake squeal differs depending on the contact condition between the pad and the disk rotor, the usage situation, etc., but the frequency of the brake squeal that is most likely to occur can be specified by the combination of the caliper mount 14 and the steering knuckle 10. For this reason, by using the design method of the steering knuckle 10 of the present embodiment, it is possible to suppress the brake squeal that is most prominently generated.

  In the present embodiment, a steering knuckle used for a strut suspension is shown as an example of the steering knuckle 10, but the shape of the steering knuckle is changed to match the torsional resonance frequency of the caliper mount to which the torsional resonance frequency is attached. Therefore, if the steering knuckle is used as a dynamic damper, the shape of the steering knuckle, the portion for changing the shape, the method for changing the shape, etc. are arbitrary, and the same effects as in the present embodiment can be obtained. . In the case of a steering knuckle used for a double double wishbone type suspension, the same effect can be obtained by changing the shape of the steering knuckle to be a dynamic damper, as in this embodiment.

  Further, the shape change of the steering knuckle is not limited to the build-up and the shaving, but can be performed by, for example, bending.

It is explanatory drawing explaining the fixed body containing the steering knuckle designed with the design method of the steering knuckle which concerns on this embodiment. It is a flowchart explaining the procedure of the design method of the steering knuckle which concerns on this embodiment. It is explanatory drawing explaining the vibration characteristic of the fixed body before and behind the shape change of the steering knuckle by the steering knuckle design method which concerns on this embodiment.

Explanation of symbols

10 Steering knuckle, 10a Opening part, 10b, 10c, 10d, 10e, 10f Protrusion part, 12 caliper, 14 caliper mount, 14a mount body, 16 hatching part, 18 fixed body, P peak value.

Claims (3)

Steps for basic steering knuckle design,
Obtaining vibration characteristics of a caliper mount connected to the steering knuckle;
Forming a fixed body in which the caliper mount is fixed to the steering knuckle, and simulating vibration characteristics of the entire fixed body when the caliper mount is vibrated based on the vibration characteristics;
Based on the vibration characteristics of the stationary body, changing the shape of the steering knuckle to suppress the peak value of the vibration characteristics and causing the steering knuckle to function as a dynamic damper with respect to the caliper mount;
Repeating the simulation and shape change of the vibration characteristics of the fixed body after the shape change, and dropping the fixed body into the desired vibration characteristics;
A method for designing a steering knuckle characterized by comprising:   The steering knuckle design method according to claim 1, wherein the shape change of the steering knuckle is performed by overlaying or shaving. The steering knuckle design method according to claim 2, wherein the steering knuckle changes a vibration state of a protrusion of the steering knuckle by the build-up or shaving.

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