JP2017123448A - Filtering method of electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filtering method of an electronic control device which can effectively suppress immunity noise and contributes to an improvement in the degree of freedom of a sensor arrangement location.SOLUTION: The filtering method of an electronic control device 1 having a control board 6, a sensor 3, and a housing 5 made of resin, includes: electrically connecting the control board 6 and the sensor 3 to each other through a spring member 4 at a plurality of portions in the housing 5; specifying whether each of the plurality of portions is a first portion where a noise decreases by increasing the number of windings of the spring member 4 or a second portion where the noise decreases by reducing the number of windings of the spring member 4; making the number of windings of the specified spring member 4 of the first portion larger than the designed number of windings of the specified spring member 4 of the first portion; and making the number of windings of the specified spring member 4 of the second portion smaller than the designed number of windings of the spring member 4 of the specified second portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a filtering method for an electronic control device in which a casing is formed of resin.

  Conventionally, an electronic control unit (ECU (Electronic Control Unit)) having an aluminum casing has been widely put into practical use. The aluminum structure electronic control unit was able to reflect the influence of immunity noise from external equipment. In recent years, a large number of electronic control devices that perform various controls of in-vehicle parts have been provided, and a low-cost resin such as PBT (polybutylene terephthalate) has come to be used in many cases.

  By the way, as a method of suppressing immunity noise, for example, Patent Document 1 discloses a method of adjusting noise of the spring material by suppressing the noise by increasing the number of turns of the spring material installed in the housing. (For example, refer to Patent Document 1).

JP 2013-110257 A

  An electronic control unit whose housing is made of resin is inexpensive but has a seal dress, so the control board and sensor mounted inside are easily affected by external immunity noise (hereinafter also simply referred to as noise). There is a drawback.

  Patent Document 1 described above is configured to suppress noise by increasing the number of turns of the spring. However, in a resin-made electronic control device, the frequency of resonance changes depending on the part, and therefore, noise may not be suppressed depending on resonance (frequency) characteristics simply by increasing the number of turns as in Patent Document 1.

Then, the arrangement of the control board and the sensor becomes a position taking noise into consideration, and the degree of freedom in design is limited. In some cases, other members such as EMI filter elements are required, which increases costs. Therefore, there is a need for a filtering method for an electronic control device that can surely suppress immunity noise and contribute to an improvement in the degree of freedom of sensor placement. At this stage, no such technology was disclosed.

  Accordingly, it is an object of the present invention to provide a filtering method for an electronic control device that can effectively suppress immunity noise and contribute to an improvement in the degree of freedom of a sensor arrangement location.

One idea is that
A filtering method for an electronic control device having a control board, a sensor, and a resin casing,
Electrically connecting the control board and the sensor via a spring material at a plurality of sites in the housing;
Each of the plurality of portions is a first portion where noise is reduced by increasing the number of turns of the spring material, or is a second portion where noise is reduced by reducing the number of turns of the spring material. To identify
The number of turns of the spring material of the specified first part is made larger than the design number of turns of the spring material of the specified first part, and the number of turns of the spring material of the specified second part Is made smaller than the designed number of turns of the spring material of the specified second part. A filtering method for an electronic control device is provided.

  According to the above configuration, first, a plurality of portions are “first portions” in which noise is reduced by increasing the number of turns of the spring material, or noise is reduced by reducing the number of turns of the spring material. Since it is specified whether it is “two parts”, the resonance frequency characteristic of each part can be accurately grasped. In addition, by adjusting (tuning) the number of turns of the spring material at the specified part, the inductance component of the spring material is adjusted and the resonance point (resonance frequency) of the noise shifts, so that the immunity noise is effectively reduced. Can be suppressed. Then, it is not necessary to arrange the sensor in consideration of immunity noise as in the prior art, and the degree of freedom of the sensor arrangement location can be improved.

  According to one embodiment of the present invention, immunity noise can be effectively suppressed and contribution to improvement in the degree of freedom of the sensor placement location can be achieved.

It is a disassembled perspective view explaining the structure of an electronic controller. It is a disassembled side view explaining the structure of an electronic controller. It is a figure explaining a resonant frequency changing with the position of the control board of the electronic controller which concerns on this embodiment. It is a graph which shows the noise result in the winding number increase / decrease of sensor 3L and sensor 3R. It is the graph which measured S parameter of sensor 3L, adjusting the number of turns. A shows the result of 27 windings, and B shows the result of 36 windings. It is a graph which shows the sensor fluctuation value in the immunity noise of the sensor 3L, A shows the result of 27 windings, B shows the result of 36 windings.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted.

  FIG. 1 is an exploded perspective view illustrating the configuration of the electronic control device. FIG. 2 is an exploded side view illustrating the configuration of the electronic control device. FIG. 2 shows a state in which the upper cover material is removed for the sake of explanation. The electronic control device 1 of this embodiment is an ECU (Electronic Control Unit) for a vehicle, and can be suitably implemented particularly for an electric brake system equipped with an active booster.

  The electronic control device 1 includes a support base 2, a sensor 3, a coil spring 4 (corresponding to a spring material), a housing part 5, and a control board 6.

  The support base 2 has a shape capable of supporting a plurality of sensors 3 on the upper surface. The position of the sensor 3 arranged on the upper surface of the support base 2 is arbitrary, and the design can be changed as appropriate.

  The sensor 3 is a hydraulic pressure sensor in the present embodiment, and a protrusion 31 as an input part is formed on the upper part.

  The casing 5 is made of resin, and includes a case material 51 that houses the coil spring 4 and the like, and a cover material 52 that covers the upper surface of the control board 6 disposed on the upper surface of the case material 51. The cover material 52 is detachably connected to the case material 51. The control board 6 has a plurality of circuit elements 61 and the like.

  The plurality of sensors 3 arranged on the upper surface of the support base 2 and the control board 6 are electrically connected by a coil spring 4 housed in a case material 51 to form a connection portion.

  More specifically, the lower end of the coil spring 4 housed in the case material 51 is electrically connected to the protrusion 31 of the sensor 3 in accordance with a predetermined location on the lower surface of the control board 6.

  After each member is arranged as described above, the screw member 7 is inserted into the screw hole of the case member 51 and screwed into the screw hole provided on the upper surface of the support base 2 to assemble the electronic control device 1.

  In the electronic control device 1 of the present embodiment, the number of turns of the coil spring 4 that can reliably reduce immunity noise in each of the connection portions formed by the sensor 3, the control board 6, and the coil spring 4 is reduced. It is characterized by being tuned and filtered. This point will be specifically described below.

  In the electronic control device 1 of the present embodiment, since the casing 5 is made of resin, the control board 6 and the sensor 3 are easily affected by immunity noise from the outside, and the sensor 3 may malfunction.

  Further, since the electronic control device 1 of the present embodiment is made of resin and has a rectangular shape, the resonance frequency of the immunity noise at each connection portion of the control board 6 exhibits different characteristics as shown in FIG. In the illustrated example, the resonance frequency is 2 GHz at the sensor 3L, and the resonance frequency is 1.5 GHz at the sensor 3R.

  Therefore, the electronic control device 1 having the resin casing 5 needs to introduce a filtering method that effectively reduces the influence of immunity noise when the sensor 3 is arranged.

  Therefore, in this embodiment, filtering is performed on each connection site. In short, each of the formed connection parts is a “first part” in which noise is reduced by increasing the number of turns of the coil spring 4, or noise is reduced by reducing the number of turns of the coil spring 4. Is the “second part” that decreases. Then, the number of turns of the coil spring 4 arranged at the specified first part is made larger than the designed number of turns, and the number of turns of the coil spring 4 arranged at the second part is made smaller than the designed number of turns so that the inductance component of the coil spring 4 This is a technique to reduce resonance of immunity noise.

  The above filtering method will be specifically described with reference to the drawings.

  In FIG. 1, a plurality of sensors 3 are arranged on the upper surface of the support base 2. The sensor 3 disposed at the connection site L is referred to as sensor 3L, and the sensor 3 disposed at the connection site R is referred to as sensor 3R.

  First, a coil spring with a winding number of 1, a coil spring with a winding number of 7, and a coil spring with a winding number of 13 are prepared, and the three types of coil springs are sequentially connected to the sensor 3L and the sensor 3R, and noise of a frequency of 0.5 GHz to 3 GHz. And examined the effect of noise. The result is shown in FIG. A shows the noise value of sensor 3L and sensor 3R when the number of turns is 1, B shows the noise value of sensor 3L and sensor 3R when the number of turns is 7, and C shows the sensor 3L and sensor when the number of turns is 13. The 3R noise value was shown.

The resonance frequency varies depending on the wiring impedance and the location of the sensor 3. As shown in FIG. 4, for the wiring impedance of the sensor 3L arranged at the connection site L, the influence of noise can be reduced in the frequency range of 0.5 GHz to 3 GHz by increasing the number of turns of the coil spring 4. I understand. In other words, the sensor 3L corresponds to “a first part where noise is reduced by increasing the number of turns of the spring material”. Further, the wiring impedance of the sensor 3R arranged in the connection part R is not equal to that of the coil spring 4. It can be seen that the influence of noise can be reduced in the frequency range of 0.5 GHz to 3 GHz by reducing the number of turns. In other words, the sensor 3R corresponds to “a second portion where noise is reduced by reducing the number of turns of the spring material”.

  Next, adjustment (tuning) of the number of turns of the coil spring 4 that reduces immunity noise at the specified connection portion will be described. Hereinafter, the coil spring 4 connected to the sensor 3L arranged in the connection site L will be described as an example, but the same technique is also implemented in other connection sites.

  The following description will be developed assuming that the number of turns at the time of designing the coil spring 4 arranged in the sensor 3L is “27 turns”.

  As shown in FIG. 4, the sensor 3 </ b> L is disposed in the connection portion L where the number of turns of the coil spring 4 can be reduced. Therefore, the coil spring 4 wound more than “27 windings” which is the designed number of windings is arranged on the sensor 3L.

  FIG. 5 shows a result obtained by actually measuring the S parameter of the sensor 3L by changing the number of turns of the coil spring. A shows the result when a coil spring of “27 windings” that is the designed number of turns is used, and B shows the result when a coil spring of “36 turns” is used.

  When attention is paid to the high frequency immunity noise of 1 GHz to 2 GHz, the direction using the “36 winding” coil spring (FIG. 5B) can suppress the S parameter value within −20 dB. On the other hand, when a “27-winding” coil spring is used (FIG. 5A), it can be seen that the S parameter value is −40 dB, which is considerably affected by noise.

  FIG. 6 shows sensor fluctuations due to immunity noise of the sensor 3L. A shows the sensor fluctuation when the coil spring of “27 windings” which is the designed number of turns is used, and B shows the sensor fluctuation when the coil spring of “36 windings” is used.

  When a “27 winding” coil spring is used, the sensor value fluctuates to around −0.35 due to immunity noise. On the other hand, when a “36 winding” coil spring is used, the fluctuation of the sensor value can be suppressed to −2 or less. Therefore, for example, in the connection part L where the sensor 3L is arranged, it is preferable to arrange the coil spring 4 in which the number of turns of the coil is increased from 27 to 36 with respect to the resonance frequency of 1.6 GHz to 2 GHz.

  The above-described method is an example, and the number of turns of the coil spring 4 that can reliably reduce immunity noise is determined in accordance with the specific matter of whether each connection site where the sensor 3 is arranged is “first site” or “second site”. Each can be tuned and filtered.

  When the filtering method described above is performed, the inductance component of the coil spring is adjusted by appropriately increasing or decreasing the number of turns of the coil spring, and the resonance point of noise shifts, so that immunity noise can be effectively suppressed. Therefore, it is not necessary to arrange the sensor in consideration of immunity noise as in the prior art, and the degree of freedom of the sensor arrangement location can be dramatically improved.

  The embodiment of the filtering method of the electronic control device has been described above, but the present invention is not limited to the above embodiment and the like, and various modifications, within the scope of the gist of the present invention described in the claims, Improvements are possible.

DESCRIPTION OF SYMBOLS 1 Electronic controller 2 Support stand 3 Sensor 31 Projection part 4 Coil spring 5 Case part 51 Case material 52 Cover material 6 Control board

Claims (1)

A filtering method for an electronic control device having a control board, a sensor, and a resin casing,
Electrically connecting the control board and the sensor via a spring material at a plurality of sites in the housing;
Each of the plurality of portions is a first portion where noise is reduced by increasing the number of turns of the spring material, or is a second portion where noise is reduced by reducing the number of turns of the spring material. To identify
The number of turns of the spring material of the specified first part is made larger than the design number of turns of the spring material of the specified first part, and the number of turns of the spring material of the specified second part Is made smaller than the design number of turns of the spring material of the specified second part.

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