JPH0337533A - Damping force detector for vehicle - Google Patents

Abstract

PURPOSE:To facilitate handling of a detector such as attachment and transportation and to make it possible to adjust the characteristics with the detector itself other than a rod by constituting a package with a piston rod housing and a fixing member for piezoelectric elements. CONSTITUTION:Part of damping force which is applied on a rod 4 strains the rod 4. At this time, strain around a detecting part is divided into the strain which is absorbed with a screw part of a rod screw 20 and the strain which deforms the screw 20 and a housing 30. The strained housing 30 applies a load on parts such as a retainer and the like beneath the retainer through a sensor screw 40, and strain is imparted. The load becomes the uniformly distributed load through the retainer 50 in contact with the tapered surface of the screw 40. Thus, strain is imparted in piezoelectric elements 60. Since the piezoelectric elements 60 are polarized beforehand, the elements 60 output electric charge in response to the amount of the strain. The output charge becomes the output corresponding to the damping force through an electrode plates 70 and lead wires 90.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a damping force detector for a vehicle that is attached to a rod of a shock absorber of a vehicle and detects the damping force of the shock absorber.

[Conventional technology]

Conventionally, as this type of detector, for example, Japanese Patent Application Laid-Open No. 636238
As shown in the above publication, a shock absorber in which a detector made of a piezo element is housed directly within the rod of the shock absorber has been proposed. This structure allows the detector to sense a portion of the damping force applied to the rod, thereby accurately detecting the road surface condition.

[Problem to be solved by the invention]

In this structure, the detection part functions as a detector only after it is incorporated into the front of the shock absorber. In other words, the detection part alone is not sufficient as a product and is inconvenient to handle.Furthermore, in the post-processing process to increase the reliability of the detector, it is necessary to process the entire rod, so it is desirable to improve this workability. It will be done.

Therefore, in the present invention, the detection part is made into an independent pancage structure, which can be used immediately by simply attaching it to the mouth, and which is easy to handle in vehicles without the need for post-processing when assembled in a lot. The purpose is to provide a damping force detector for

[Means to solve the problem]

In order to achieve the above object, the present invention provides a housing that is attached and fixed to a piston rod connected to a piston in a shock absorber and that is distorted in response to distortion of the piston rod; A piezoelectric element that generates an electric charge according to the distortion of a piston rod, and a fixing member that is screwed into the housing and presses and fixes the piezoelectric element in the housing, and the housing and the fixing member form a pan cage structure. It is composed of

[Function] In the present invention, the piezo element is press-fixed in a dedicated housing by a fixing member, packaged by the housing and the fixing member, and then removed and fixed to a piston rod so that the pan cage is subjected to distortion. . As a result, it becomes possible to handle the detector as a package when handling and transporting the detector, and it is also possible to adjust the characteristics of the package itself without incorporating it into a lot.

[Example] Next, an example of the present invention will be described in detail based on the drawings.

FIG. 2 shows a longitudinal sectional view of a variable damping force shock absorber incorporating this damping force detector.

As shown in the figure, in the variable damping force type shock absorber 1, a piston 3 is fitted inside a cylinder 2 so as to be slidable in the axial direction (indicated by arrows A and B in the figure). . This piston 3 is connected to one end of a piston rod 4, while the other end of the piston rod 4 is fixed to a shaft 5. The lower part of the outer shell 2a is connected to the lower arm 2c of the vehicle via the suspension bushing 2b, while the upper part of the shaft 5 is connected to the hair ring 6,
Each is connected to the vehicle body 8 via a vibration isolating rubber 7.

A piezo actuator 11 that changes the damping force of the variable damping force shock absorber 1 and a piezo type damping force detector 12 that detects the damping force are housed in a hollow portion bored in the axial direction of the piston rod 4. The piezo type damping force detector 12 is press-fixed to the hollow part of the piston rod 4 with a rod screw 13.

Next, the structure of the damping force detector 12, which is a feature of the present invention, will be explained based on FIG. The rod 4 of the shock absorber (the upper and lower passages in FIG. 2) has a structure in which the detection section 100 of the detector 12 can be housed. 20 is a front screw that fixes the housing 30 to the rod 1, and uses the screw to push the housing 30 onto the rod 1. , 30 is a metal housing of the detector 12 and contains peripheral parts including a piezo element 60. A female thread is cut inside this so that the sensor screw 40 can be inserted therein. 40 is a sensor screw that contacts the retainer 50 at a tapered portion, and the retainer 50
peripheral parts such as the housing 30 are pressed against the housing 30. 50
is a retainer which distributes the pressing force generated by the sensor screw 40 into an evenly distributed load and moves the piezo element 60
It applies a load to the Although the contact shape of the sensor screw 40 and the retainer 50 is a tapered surface and a pin angle in FIG. 1, it may be any combination of a flat surface, a tapered surface, and a rounded surface.

Reference numeral 60 denotes a ring-shaped piezo element, which is made up of one or more pieces and connected in parallel.

This piezo element 60 is pre-polarized and generates a charge in response to strain.

70 is the electrode plate, and in the figure, it stands out from the ■ side and the ○ side, but if you use it as a hodia earth, you can use only the O side,
Both types of electrode plates are arranged in contact with the piezo element 60. 8
0 is the Kien da-ji which is placed on both sides of the electrode, ■ side and ○ side.
Paste shorts and leaks on the sides, but in the case of Hodia Earth, only the Φ side is needed. This material can be any insulator, AN203, PZT, SI3
It is N4 grade. The insulating dummy 80, the electrode plate 70, and the piezo element 60 have similar shapes in FIG. Zunawara has a circular outer circumference and a hole for the lead wire in the center,
This is not the limit. Reference numeral 90 is a wire that is electrically connected to the electrode plate 70 and guides the output of the piezo element 60 to the outside.

Of the above configuration, the portion from the housing 30 to the lead wire 90 is called the detection portion 100, and this alone constitutes a single product.

Next, the operation of the attenuation detector configured as described above will be explained. The damping force generated by the shock absorber is proportional to the movement of the suspension, whose behavior changes depending on the size of the unevenness of the road surface, so measuring the damping force means measuring the condition of the road surface. If this can be measured, combined with a mechanism that changes the damping force and spring constant, it is possible to achieve both ride comfort and handling stability at a high level.

In the above configuration, most of the damping force applied to the rod 4 is transmitted to the vehicle body, but a portion of it distorts the rod 4. At this time, the strain around the detection part is absorbed by the threaded part of the front screw 20, and the distortion around the front screw 20 and the housing 3 are absorbed by the screw part of the front screw 20.
It can be divided into 0 and those that distort. distorted housing 3
0 similarly connects the retainer 50 through the sensor screw 40.
Apply a load to the following parts and distort them. The load is divided into equal parts by the retainer 50 that contacts the tapered surface of the sensor screw 40, thereby distorting the piezo element 60. Since the piezo element 60 is roughly polarized, it outputs a charge in accordance with the amount of strain. The output electric charge is transferred to the electrode plate 70. It is led to an external processing circuit (not shown) via a lead wire 90. As described above, a part of the damping force applied to the lot reaches the piezo element 6 and is output, so that an output corresponding to the damping force can be obtained.

Next, other embodiments of the present invention will be described. Figure 3 shows a cross-sectional view of the lot, and shows the lot as
Divide into 4a and 4b, and insert housing 3 between both ends.
0 is connected as part of the lot.

In addition, in the embodiment shown in FIG. 1, the detector housing 30 is fixed in the lot 4 with a front screw 20, but it is also possible to cut a screw in the housing 30 itself and fix it directly in the lot 4 with a screw. You may also do so.

[Effects of the Invention] As described above, in the present invention, since the detection section has a single cane structure, it is extremely easy to install, transport, etc. the detector composed of a plurality of parts.
In addition, the characteristics of the detector itself can be adjusted independently of the lot, making it highly practical.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a detector showing one embodiment of the present invention, and FIG.
This figure is a block diagram of a shock absorber incorporating the detector shown in FIG. 1, and FIG. 3 is a sectional view of a detector showing another embodiment of the present invention. 1... Shock absorber, 2... Cylinder, 3...
...Piston, 4.4a, 4b...Piston Rondo,
12... Damping force detector, 20... Front screw 530... Housing 40... Sensor screw 50... Retainer, 60... Piezo element, 100...
··Detection unit.

Claims (3)

[Claims] (1) A housing that is attached and fixed to a piston rod that is connected to a piston in a shock absorber and is distorted in response to distortion of the piston rod; A vehicle comprising a piezoelectric element that generates electricity, and a fixing member that is screwed into the housing and presses and fixes the piezoelectric element in the housing, and the housing and the fixing member form a package structure. Damping force detector. (2) The damping force detector for a vehicle according to claim 1, wherein the housing is built into the piston rod and fixed by a member that is threaded onto the piston rod. (3) The damping force detector for a vehicle according to claim 1, wherein the housing is fixed so as to be interposed between the divided piston rods.