Patent Grant
9039430
The present invention relates to an electric connector mounted to a shielded cable for transferring information that is transmitted and received between train-information transmission/reception apparatuses, a train-information transmission/reception system using the electric connector, and a method for connecting the electric connector.
In an electric apparatus to be connected to a plurality of external apparatuses, various types of signal lines are generally wired in a high density due to a restriction in the size of a main unit of the apparatus. Particularly, in a train-information transmission/reception apparatus, which is one of the electric apparatuses incorporated in a railway vehicle, a plurality of signal lines are combined in a single connector so as to transmit various signals ranging from an analogue signal to a high-speed digital signal to and from a plurality of apparatuses having different functions. Therefore, a plurality of types of signals may exist in a mixed manner in a single connector.
A shielded cable, which is one of the media for transmitting a signal, is mainly configured with a conductor for transmitting signals and a shield (a shielded layer) covering the conductor. For example, in a conventional technique disclosed in Patent Literature 1, the following methods have been adopted to ground the shielded layer to a frame ground of the train-information transmission/reception apparatus.
A first method includes processing a shielded layer in a pigtail shape at a position farthest from a train-information transmission/reception apparatus (for example, a connector to be arranged in a connection portion between vehicles) and grounding the pigtail to a vehicle body. A second method includes processing a shielded layer in a pigtail shape near a train-information transmission/reception apparatus and providing a connector pin at an end portion of the pigtail. In this method, when the connector is connected to the train-information transmission/reception apparatus, the ground is secured via the connector pin, a GND line mounted to a substrate of the train-information transmission/reception apparatus, and a frame ground of the train-information transmission/reception apparatus.
Patent Literature 1: International Publication No. WO2007/007495 (paragraphs 0035 to 0042, FIGS. 7 to 10)
However, in the first method, because the ground is secured at a position far from the train-information transmission/reception apparatus, noise applied to the shielded layer near the train-information transmission/reception apparatus cannot be fully released to the ground. This results in a problem that the noise may affect the train-information transmission/reception apparatus. Meanwhile, in the second method, because the shielded layer is grounded to the frame ground via the substrate, there is a problem that the noise from the shielded layer may be radiated to a semiconductor element and the like on the substrate and affects the train-information transmission/reception apparatus.
The present invention has been achieved in view of the above problems, and an object of the present invention is to provide an electric connector, a train-information transmission/reception system, and a method for connecting the electric connector that can reduce an influence of noise applied to an in-vehicle wire cable on a train-information transmission/reception apparatus.
There is provided an electric connector according to an aspect of the present invention that is, for allowing information transmission/reception apparatuses incorporated in a plurality of vehicles constituting a train to transmit and receive train information in an interconnecting manner via an in-vehicle cable, interposed between the in-vehicle cable and the information transmission/reception apparatus, wherein the in-vehicle cable internally includes a plurality of signal lines that transmit the train information and an electrically-conductive shielded layer surrounding the signal lines, one end of a ground line is connected to the shielded layer, the signal lines are connected to connector pins that are installed in an electrically-conductive connector case, which is a casing of an electric connector, and are electrically insulated from the connector case, a casing ground is provided to a casing of the information transmission/reception apparatus, and a plurality of contact pins electrically insulated from the casing and electrically connected to the connector pins are provided to the casing of the information transmission/reception apparatus, and the other end of the ground line is connected to the connector case in a detachable manner, and the connector case is electrically connected to the casing of the information transmission/reception apparatus in a state where the contact pins and the connector pins are respectively connected to each other.
According to the present invention, a ground line connected to a shielded layer of an in-vehicle wire cable is configured to be connected to a connector case and grounded to a frame ground via a casing of a train-information transmission/reception apparatus when signal lines of the in-vehicle wire cable and contacts installed in the train-information transmission/reception apparatus are connected to each other, and therefore it is possible to reduce an influence of noise applied to the in-vehicle wire cable on the train-information transmission/reception apparatus.
Exemplary embodiments of an electric connector, a train-information transmission/reception system, and a method for connecting the electric connector according to the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments.
The transmission/reception apparatus 10 controls various types of information (train information) for monitoring apparatuses incorporated in a train in an interconnecting manner, and transmits and receives the train information across the vehicles 1. Although two transmission/reception apparatuses 10 are incorporated in each of first vehicles on both sides and one transmission/reception apparatus 10 is incorporated in each of vehicles 1 other than the first vehicles in
More specifically, the transmission path 11 includes an in-vehicle wire cable 11a (hereinafter, simply “wire cable 11a”), a jumper cable 11b that is connected across the vehicles 1, and connectors 31 provided on the opposing sides of the vehicle 1 and each interposed between the wire cable 11a and the jumper cable 11b.
One end of the wire cable 11a is connected to the transmission/reception apparatus 10, and the other end is connected to the connector 31. The wire cable 11a and the jumper cable 11b are connected to each other via the connector 31. Therefore, the transmission/reception apparatus 10 incorporated in one vehicle 1 shown on the left side of
A CPU board or the like for performing various processes by using the train information and the like is mounted on a lower side surface of the electric connector 12, and for example, the CPU board and the electric connector 12 are connected to a printed circuit board 46, which is explained later. Although one wire cable 11a is connected to the electric connector 12 shown in
The wire cable 11a, which is grounded by the first method described above, is shown on the right side of the transmission/reception apparatus 10. That is, one end of a shielded ground line 32a is connected to the shielded layer 45 shown in
In this manner, in the first method, only one end of the wire cable 11a is grounded (one-end grounding). In the case of one-end grounding, anti-noise performance is degraded as compared to a case of both-end grounding because a potential difference is generated on the wire cable 11a. However, in a railway vehicle, because a high voltage is used, a ground-fault current may flow from one end to the other end when the both ends are grounded. Therefore, in the railway vehicle, it is a common practice to ground one end of the wire cable 11a, due to the reasons specific to railway vehicles.
The wire cable 11a, which is grounded by the second method, is shown on the left side of the transmission/reception apparatus 10. That is, one end of a shielded ground line 32b is connected to the shielded layer 45 shown in
With this configuration, noise applied to the shielded layer 45 from various apparatuses arranged near the wire cables 11a flows to the casing ground 33 via the casing of the electric connector 12 and the casing of the transmission/reception apparatus 10. That is, this noise flows to the casing ground 33 without passing through the substrate of the transmission/reception apparatus 10. A configuration of the electric connector 12 is explained below in detail.
In
An opening 24 for allowing the signal lines 41 and the ground line 32 to be introduced into the case 12a is provided on the cable introducing surface 20. The electrically-conductive terminal 12c mounted to the end portion of the ground line 32 is connected to the side surface 23 of the case 12a with a terminal mounting screw (a fixing member) 12b in a detachable manner. The terminal 12c is fixed by the terminal mounting screw 12b for an easy maintenance. In the present embodiment, for example, the terminal 12c is connected to the case 12a by using the terminal mounting screw 12b; however, the mounting member is not limited to a screw. A fastening member other than a screw or a fixing member can be also used.
Furthermore, a connector connection unit 12d including pin holes 14 formed to include a plurality of connector pins (for example, jack pins) is attached on the case 12a. The connector pins are installed in the electrically-conductive connector case 12a in a state where the connector pins are electrically isolated from the connector case 12a. The connector connection unit 12d is mounted inside the case 12a in such a manner that the connector connection unit 12d is surrounded by the case 12a except for the side of the pin holes 14.
The sheath 34 of the wire cable 11a shown in
The processed portion 16 of the wire cable 11a indicates a portion for processing the shielded layer 45. The shielded layer 45 and the ground line 32 are electrically connected to each other on the portion.
Dimensions of the housing 17 shown in
By forming the housing 17 in the shape mentioned above, when the outer circumferential surface of the case 12a is thought of as a convex portion and the inner circumferential surface of the housing 17 as a concave portion, the convex portion is fitted into the concave portion and the outer circumferential surface of the case 12a and the inner circumferential surface of the housing 17 are brought into surface contact with each other. That is, the case 12a is formed to be capable of being brought into contact with the inner circumferential surface of the housing 17 in a state where the contact pins 15 and the connector pins are engaged with each other. Although it is preferred to form the case 12a such that all surfaces of the outer circumferential surface thereof are brought into contact with the inner circumferential surface of the housing 17, it may be configured such that only a part of the surfaces (for example, the side surfaces 23) is brought into contact with the inner circumferential surface of the housing 17. Also in this case, as compared to the conventional second method in which the ground is secured via the pins inserted into the pin holes 14, the impedance is greatly reduced, and further with respect to vibration generated while the train is running, mechanical and electrical connection of the electric connector 12 is stabilized.
Furthermore, it is also possible to attach the case 12a to the contact pins 15 without using the housing 17. In this case, the impedance is increased as compared to the case of using the housing 17 because the end portion of the case 12a that surrounds the connector connection unit 12d and the casing 3 are brought into point contact with each other. However, the impedance is smaller than the impedance in the case of using the conventional second method.
A dotted line indicated by a symbol A represents a path of the noise flowing to the casing ground 33 via the “conventional shielded ground line” shown in
On the other hand, a dotted line indicated by a symbol B represents a path of the noise when the electric connector 12 according to the present embodiment is used. That is, the noise applied to the wire cable 11a flows to the casing ground 33 via the terminal 12c, the case 12a, and the casing 3 without passing through the printed circuit board 46.
The distance L1 and the length L2 shown in
However, there may be a case where about ten lines including the signal lines 41 and the ground line 32 are introduced into the opening 24 shown in
Meanwhile, considering the workability when connecting the ground line 32 to the inside of the case 12a (for example, the side surface 23), the length L2 of the ground line 32 is set to a length with a margin. Although the flexibility of the position to connect the terminal 12c is increased so that the workability of the ground line 32 is improved as the length L2 is increased, the impedance of the ground line 32 is increased and the anti-noise performance is degraded as the length L2 is increased. Therefore, it is desired that the length L2 is set to a length with which both the workability of the ground line 32 and the anti-noise performance can be achieved.
The present inventors have found optimum values of the distance L1 and the length L2 through experiments. The optimum values are explained below with reference to
The data shown in
For example, when L2 is 220 millimeters in No. 1, the determination is NG with respect to both the noise of +2 kilovolts and of −2 kilovolts.
When L2 is 80 millimeters in No. 2, the number of operations of the WDT is zero with respect to both the noise of +2 kilovolts and the noise of −2 kilovolts. This can be considered that the impedance of the ground line 32 was sufficiently reduced so that the anti-noise performance was improved.
Subsequently, the operation was checked when L2 was changed to be longer than 80 millimeters to check a range in which the determination is “OK”.
Nos. 3 and 4 show data obtained when L2 was changed to 160 millimeters and 180 millimeters, where both determinations are “NG”.
In Nos. 5 and 6, experiments were conducted twice with L2 set to 140 millimeters for confirmation, where both determinations are “OK”.
Subsequently, experiments were performed for Nos. 7 to 9 to check a range from 140 millimeters to 160 millimeters.
In No. 7, when L2 is 150 millimeters, the determination is “NG”. The number of operations of the WDT at this time is 5 for the noise of −2 kilovolts. Meanwhile, No. 8 indicates data obtained when a shielded copper tape is applied to a section of the distance L1 while L2 is left unchanged to be 150 millimeters. However, the determination is “NG”.
No. 9 indicates data obtained when L2 was set to 140 millimeters again. In this case, the distance from the case 12a to the processed portion 16 is increased by changing the position of the shield clamp 52 with the length L2 of the ground line 32 left unchanged (see
More specifically, Nos. 5 and 6 in
Meanwhile, data of No. 9 in
Data of No. 10 are data obtained when the length L2 of the ground line 32 is decreased from 140 millimeters to 120 millimeters with the distance L1b left unchanged. The number of operations of the WDT at this time is zero for both the noise of +2 kilovolts and the noise of −2 kilovolts. It is found that the impedance of the ground line 32 is decreased so that the anti-noise performance is improved simply by decreasing the length L2 of the ground line 32 by 20 millimeters.
In this manner, both the anti-noise performance and the assembling workability of the case 12a can be achieved with such a configuration that the distance L1 from the processed portion 16 to the cable introducing surface 20 is equal to or shorter than 65 millimeters and the length L2 of the ground line 32 from the processed portion 16 to the terminal 12c is equal to or shorter than 120 millimeters.
A case where the case 12a including a cable clamp 50 is employed is explained next.
The case 12a and the cable clamp 50 shown in
Generally, a section from the processed portion 16 to the cable clamp 50 is covered by a protective net (not shown) for protecting the whole cable. In this case, the end of the protective net is inserted between the cable clamp 50 and the cable and fixed by the cable clamp 50. Therefore, the cable including the ground line 32 processed at the processed portion 16 is introduced into the case 12a in a state of being accommodated in the protective net. In other words, when the end of the ground line 32 is connected to the cable clamp 50 or to outside of the case 12a, it is not possible to protect the ground line 32 and the like.
Because the electric connector 12 according to the present embodiment has a configuration in which the ground line 32 is connected inside the case 12a, the section from the processed portion 16 to the cable clamp 50 can be protected by the protective net, and the anti-noise performance of the signal lines 41 can be improved.
By providing the terminal block 51 on the inner circumferential surface of the case 12a, the workability in screwing the terminal mounting screw 12b on the side surface 23 of the case 12a is improved, and it becomes easy to manage the torque of the terminal mounting screw 12b. Because the terminal 12c can be solidly fixed to the case 12a, the contact impedance between the ground line 32 and the case 12a can be reduced as a result.
It is desirable to set the position for connecting the terminal 12c, for example, near the opening 24 shown in
An operation is explained below. One end of the ground line 32 is connected to the shielded layer 45 outside the case 12a shown in
Meanwhile, on the casing 3 of the transmission/reception apparatus 10, the casing ground 33 shown in
Subsequently, when the case 12a configured in the above manner is connected to the contact pins 15, the shielded layer 45 is connected to the casing ground 33 via the ground line 32, the terminal 12c, the case 12a, and the casing 3 as shown in
Furthermore, as shown in
Further, when the terminal block 51 shown in
Although the connector pins have been explained as jack pins and the contact pins 15 have been explained as plug pins as an example in the above descriptions, the connector pins can be plug pins and the contact pins 15 can be jack pins.
As described above, the electric connector and the train information transmission/reception apparatus according to the present embodiment are electrically connected to the casing 3 of the transmission/reception apparatus 10 in a state where the contact pins 15 and the connector pins are connected to each other, and include the case 12a on which the terminal block 51 that is interposed between the case 12a and the electrically-conductive terminal 12c provided on the other end of the ground line 32 and fixes the terminal 12c by using the terminal mounting screw 12b is provided. Therefore, the noise propagating through the shielded layer 45 in the wire cable 11a can be released to the frame ground (the casing ground 33) without passing through an electric circuit inside the transmission/reception apparatus 10. Particularly, the noise applied to the wire cable 11a near the transmission/reception apparatus 10 can be effectively released to the casing ground 33. In addition, because a frame ground pin is not needed in the connector connection unit 12d shown in
Furthermore, the electric connector 12 according to the present embodiment is configured such that the casing ground is completed by electrically connecting the connector case 12a to which the ground line 32 is connected and the housing 17 right before the contact pins 15 and the connector pins are electrically connected to each other. That is, before the contact pins 15 are inserted into the connector pins, a countermeasure is taken against the noise by providing grounding of the shielded layer 45. Therefore, the electric connector 12 according to the present embodiment can effectively suppress the influence of noise applied to an in-vehicle wire cable on the train information transmission/reception apparatus.
In the present embodiment, although a configuration in which the inner circumferential surface of the housing 17 is brought into electrical contact to the outer circumferential surface of the case 12a has been explained, if it is configured that an outer circumferential surface of the housing 17 is brought into electrical contact with an inner circumferential surface of the case 12a, same effects can be achieved.
The electric connector and the train-information transmission/reception system described in the present embodiment are only examples according to the present invention, and these can be combined with other well-known techniques, and it is needless to mention that the electric connector and the train-information transmission/reception system can be configured while modifying them without departing from the gist of the invention, such as omitting a part of their configurations.
As described above, the present invention can be applicable to both an electric connector mounted to a train-information transmission/reception apparatus and a train-information transmission/reception system, and the present invention is particularly useful as an invention that can reduce an influence of noise applied to a shielded cable on an information transmission/reception apparatus.
1 vehicle
3 casing
10 train-information transmission/reception apparatus
11 transmission path
11
a in-vehicle wire cable (in-vehicle cable)
11
b jumper cable
12 electric connector
12
a connector case
12
b terminal mounting screw (fixing member)
12
c terminal
12
d connector connection unit
14 pin hole
15 contact pin
16 processed portion
17 connector housing
20 cable introducing surface
21 upper surface
22 lower surface
23 side surface
24 opening
31 connector
32, 32a, 32b shielded ground line
33 casing ground
34 sheath
41 signal line
41
a conductor
41
b insulation layer
45 shielded layer
46 printed circuit board
50 cable clamp
51 terminal block
52 shield clamp
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/071147 | 11/26/2010 | WO | 00 | 4/4/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/070150 | 5/31/2012 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4405187 | Muellerr et al. | Sep 1983 | A |
| 5064388 | Paladel | Nov 1991 | A |
| 5788528 | Orr, Jr. et al. | Aug 1998 | A |
| 7753720 | Emoto et al. | Jul 2010 | B2 |
| 8684767 | Emoto et al. | Apr 2014 | B2 |
| 20090042436 | Emoto et al. | Feb 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| 19717627 | Oct 1998 | DE |
| 0073112 | Mar 1983 | EP |
| 1100161 | May 2001 | EP |
| 1902893 | Mar 2008 | EP |
| 57-182885 | Nov 1982 | JP |
| 62-128461 | Jun 1987 | JP |
| 6-337744 | Dec 1994 | JP |
| 2000-012161 | Jan 2000 | JP |
| 2005-251507 | Sep 2005 | JP |
| 2009-146229 | Jul 2009 | JP |
| WO 2007007495 | Jan 2007 | WO |
| Entry |
|---|
| International Search Report (PCT/ISA/210) issued on Feb. 22, 2011, by the Japanese Patent Office as the International Searching Authority for International Application No. PCT/JP2010/071147. |
| Written Opinion (PCT/ISA/237) issued on Feb. 22, 2011, by the Japanese Patent Office as the International Searching Authority for International Application No. PCT/JP2010/071147. |
| Japanese Office Action (Notification of Reason(s) for Refusal) dated Oct. 8, 2013, issued by the Japanese Patent Office in corresponding Japanese Patent Application No. 2012-545584, and an English Translation of the Office Action. (7 pages). |
| Written Opinion of the International Searching Authority (Translation)(Form PCT/ISA/237) issued on Feb. 22, 2011, in the corresponding International Application No. PCT/JP2010/071147. (7 pages). |
| Extended Search Report from European Patent Office dated Jun. 4, 2014, issued in corresponding European Patent Application No. 10860010.7. (11 pages). |
| Number | Date | Country | |
|---|---|---|---|
| 20130203289 A1 | Aug 2013 | US |
