JPH10190247A - Electronic unit for car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the operation of controlling arithmetic elements from becoming unstably or being broken by temperature increase and to prevent the cost from increasing owing to radiating measures, without taking radiating measures such as forced cooling inside a case by ventilation, etc., heat radiating fins, etc., to be used exclusively. SOLUTION: Concerning this electronic unit 21 for cars, the positions of individual elements 25, 26 28 and a connector 29 to be arranged are set, so that the upper region 30a where driving elements 25, 26 of large heat generation are arranged, and the lower region 30b where a controlling arithmetic element 28 vulnerable to heat increase is arranged, may be divided by a connector 29 for external connection, on the printed board 30 of a board unit 23 put in a unit case 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted electronic unit mounted in, for example, an engine room of a vehicle.

[0002]

2. Description of the Related Art An example of a conventional vehicle-mounted electronic unit will be described with reference to FIGS. The on-vehicle electronic unit 1 shown here is disclosed in Japanese Patent Application Laid-Open No. 6-216544, and includes a board unit 7 and a unit case 11 for housing the board unit 7.

As shown in FIG. 3, the board unit 7 includes a driving element 2 such as a relay which generates a large amount of heat, a control arithmetic element 3 such as a CPU which is weak against temperature rise, and a connector 4 for external connection. Are mounted on a single printed circuit board 6. The connector 4 in the board unit 7 is arranged on one end side of the printed board 6.

The unit case 11 is a box body 1 having a box shape with an open rear end and accommodating the board unit 7.
2 and a lid 13 that covers an open portion of the case main body 12. The case body 12 and the lid 13 are
Each is a molded article made of an insulating resin. At the front end of the case main body 12, there is formed a connector connection opening 9 for exposing the connector 4 on the board unit 7 to the outside of the case so that an external cable can be connected to the connector 4.

The unit case 11 has improved waterproofness in consideration of the case where the unit case 11 is disposed in an engine room or the like.
Waterproof packings 17 and 18 are provided between the connector 4 and the front wall of the case body 12 to prevent intrusion from these openings. Then, the case 1 is maintained without reducing the waterproof effect of the packings 17 and 18.
The connection pipe 15 is fitted to the upper wall portion of the case main body 12 to ensure the air permeability in the case 1, and the connection pipe 15 is connected to a hose 16 for communicating the inside of the case 11 with the vehicle interior. It has become.

[0006]

By the way, the control arithmetic element 3 mounted on the printed circuit board 6 is susceptible to heat, and if the temperature in the case 11 rises, the element itself is broken or the control operation is hindered. There is a worry that it will happen. for that reason,
When designing the vehicle-mounted electronic unit 1, it is important to consider heat dissipation so that the temperature in the case 11 is maintained within the allowable temperature range of the control arithmetic element 3.

In the on-vehicle electronic unit 1 described above, part of the heat generated by the driving element 2 is transmitted to the atmosphere in the case 11 to raise the temperature in the case. However, since the printed circuit board 6 includes a printed conductor having higher heat conductivity than air, most of the heat generated by the driving element 2 is transmitted to the printed circuit board 6.

Therefore, in the above-mentioned on-vehicle electronic unit 1,
By connecting the space in the case to the vehicle compartment by the connection pipe 15 and the hose 16, it is possible to easily discharge heat transferred from the driving element 2 to the atmosphere in the case. Each of the elements 2, 3 is arranged on the printed circuit board 6 such that the driving element 2 is located closer to the connector 4 than the control arithmetic element 3.
Is set so that the heat transmitted from the driving element 2 to the printed circuit board 6 is quickly released to the external cable connected to the connector 4.

However, the heat transmitted from the driving element 2 to the printed circuit board 6 diffuses on the printed circuit board 6 around the mounting position of the driving element 2 in all directions. Therefore, in the configuration in which the connector 4 is disposed at one end of the printed circuit board 6 as described above, the heat that diffuses from the driving element 2 to the control operation element 3 side on the printed circuit board 6, that is, Against the heat transmitted from the connector 4
Does not exhibit the heat radiation effect, and there is a concern that inconvenience may occur due to a rise in the substrate temperature on the control computing element 3 side.
Further, in order to prevent the substrate temperature on the control operation element 3 side from rising, further heat dissipation measures such as forced cooling in the case 11 by blowing air or the like and provision of heat radiation fins for the control operation element 3 are required. There is a problem that the cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the temperature of the control arithmetic element can be increased by increasing the temperature without providing a means for forcibly cooling the inside of the case by blowing air or radiating fins such as dedicated radiating fins. An object of the present invention is to provide a vehicle-mounted electronic unit that can prevent the operation from becoming unstable or damaged, and eliminate the cost increase for heat dissipation measures.

[0011]

An object of the present invention is to provide a driving element such as a relay which generates a large amount of heat, a control arithmetic element such as a CPU which is vulnerable to temperature rise, and a connector for external connection. A board unit mounted on a printed circuit board; and a unit case provided with a connector connection opening for accommodating the board unit and connecting an external connection wire to the connector on the housed board unit. In the on-vehicle electronic unit mounted on the vehicle,
In the board unit, each element and the connector are arranged such that an area where the driving element is arranged and an area where the control operation element is arranged are separated by the connector. It can be solved by a vehicle-mounted electronic unit.

In the vehicle-mounted electronic unit having the above configuration,
The heat transmitted from the driving elements to the printed circuit board diffuses on the printed circuit board through printed conductors on the printed circuit board. Then, the signal is transmitted toward the control operation element side located on the opposite side of the driving element with the connector interposed therebetween, and a connection terminal of an external connection connector is connected in the middle of the transmission path. I have. In general, the connection terminal has a larger cross-sectional area as a heat conductor than a printed conductor on a printed circuit board, and heat flows easily. Therefore, the heat transmitted from the driving element to the printed circuit board is transmitted to the connection terminal of the connector on the way to the control computing element side while diffusing on the printed circuit board, and the external cable connected to the connector. The heat is dissipated from Therefore, the control operation element can be protected from heat without providing heat radiation measures such as forced cooling and heat radiation fins, and cost increase for heat radiation measures can be eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle-mounted electronic unit according to the present invention will be described below in detail with reference to FIGS. FIG. 1 is an exploded perspective view showing an embodiment of a vehicle-mounted electronic unit according to the present invention, and FIG. 2 is a longitudinal sectional view of the vehicle-mounted electronic unit in FIG. As shown in FIGS. 1 and 2, the on-vehicle electronic unit 21 of the present embodiment is mounted in an engine room or a trunk room of a vehicle and controls other electronic circuits and electric devices mounted on the vehicle. It is composed of a unit 23 and a unit case 24 that accommodates the board unit 23.

As shown in FIG. 1, the board unit 23 includes a relay 25 and a power transistor 26, which are driving elements generating a large amount of heat, and a control arithmetic element C, which is weak in temperature rise.
A PU 28 and a connector 29 for external connection are mounted on a single printed circuit board 30.

In the connector 29, an L-shaped connection terminal 32 is held by a terminal holder 31 made of insulating resin. This connection terminal 32 is a press-formed product of a metal plate,
The base end protruding from the bottom of the terminal holder 31 is inserted into a through hole of the printed
0 is soldered to the printed conductor.

In the board unit 23, the relay 25 and the power transistor 26, which are driving elements, are arranged in an area 30a above the printed board 30, and the CPU 28, which is a control arithmetic element, is placed in the area 30a below the printed board 30.
b. These two regions 30a, 30
The connector 29 is arranged so as to traverse the center of the printed circuit board 30 so as to be separated from the printed circuit board 30 by the connector 29.

The unit case 24 comprises an upper case 33 having a substantially box-like shape with an open bottom for accommodating the board unit 23, and a substantially flat lower case 34 for covering an open portion of the upper case 33. ing. Upper case 33
Each of the lower case 34 and the lower case 34 is a molded product made of an insulating resin.

The upper case 33 has a substantially stepped shape whose height is increased in accordance with a driving element such as a relay 25 having a large height, and a connector connection opening 36 is provided at a boundary portion. Is formed. The connector connection opening 36 is a portion for connecting an external cable to the connector 29 described above, and the tip of the connection terminal 32 of the connector 29 is exposed in the connector connection opening 36.

In addition, the upper wall of the upper case 33 has a structure shown in FIG.
As shown in FIG. 7, a partition wall 37 is provided to partition the space inside the case into an upper side and a lower side. In the partition wall 37, the atmosphere in the case, which is heated by the heat generated by the driving elements such as the relay 25 and the power transistor 26 disposed in the upper region in the case, flows toward the CPU 28 which is the control arithmetic element. Has been prevented. That is, the heat transferred from the relay 25 and the power transistor 26 to the region above the case is:
It does not flow to the area below the case, but is radiated to the outside air from the case wall above the upper case 33. Relay 2
The amount of heat transmitted from the power transistor 5 and the power transistor 26 to the atmosphere in the case is very small as compared with the amount of heat transmitted from the relay 25 and the power transistor 26 to the printed circuit board 30, and no problem occurs even with such heat dissipation measures.

In the above-mentioned on-vehicle electronic unit 21 of the present embodiment, the heat transmitted from the relay 25 or the power transistor 26 as the driving element to the printed circuit board 30 is transmitted through the printed conductor on the printed circuit board 30 and printed. Diffusion on the substrate 30. Then, the power is transmitted toward the CPU 28 disposed in the area 30 b opposite to the driving elements 25 and 26 with the connector 29 interposed therebetween. In the middle of the transmission path, the connection terminal 32 of the connector 29 is provided. It is connected.

The connection terminal 32 is a press-formed product of a metal plate, as described above, and has a larger cross-sectional area as a heat conductor than the printed conductor on the printed circuit board 30, so that heat flows easily. Therefore, the relay 25 and the power transistor 26
The heat transmitted to the printed circuit board 30 is diffused on the printed circuit board 30 and is mostly transmitted to the connection terminal 32 of the connector 29 on the way to the CPU 28 side.
The heat is dissipated through the external cable.

That is, heat generated from the relay 25 and the power transistor 26 on the printed circuit board 30 is
9 prevents the signal from being transmitted to the CPU 28, and at the same time allows the connector 29 to quickly release the signal to an external cable. Therefore, the same printed circuit board 30
Various elements 25, 26, 28 mounted on the connector and connector 2
CPU 28 which is a control arithmetic element only by
It is possible to obtain an excellent heat radiation effect of suppressing the temperature rise of the semiconductor device.

Therefore, the operation of the CPU 28, which is a control arithmetic element, becomes unstable due to a rise in temperature without taking any special heat radiation measures such as forced cooling of the inside of the case by blowing air or special radiation fins. It is possible to prevent the device itself from being damaged, and it is possible to eliminate an increase in cost due to measures for heat radiation.

The specific structure of the unit case 24 and the types of elements mounted on the printed circuit board 30 are not limited to the above-described embodiment. Also,
Although the on-vehicle electronic unit of the present invention has been described as controlling the electronic circuit, electric equipment, and the like mounted on the vehicle in the above-described embodiment, the driving element having a large amount of heat generation on one printed circuit board Various electronic devices and the like having a configuration in which a board unit equipped with a control operation element having a small heat generation amount and a connector for external connection is housed in a unit case, for example,
The present invention can be applied to in-vehicle audio equipment, visual equipment, and navigation equipment.

[0025]

As described above, according to the on-vehicle electronic unit of the present invention, the area where the driving elements are arranged and the area where the control arithmetic elements are arranged in the board unit are separated by the connector. Elements and connectors are arranged in such a manner as to be described. Therefore, the heat transmitted from the driving element to the printed circuit board diffuses on the printed circuit board through the printed conductor on the printed circuit board, and the control operation arranged on the opposite side of the connector with respect to the driving element. It is transmitted toward the element side. However, along the way,
Since the connection terminal for external connection having a larger cross-sectional area as a heat conductor than the printed conductor on the printed circuit board is connected, heat transmitted to the printed circuit board is connected from the connection terminal to the connector. Heat is radiated to the outside via the external cable.

That is, the heat generated from the driving elements on the printed circuit board is prevented from being transmitted to the control operation element side by the connector, and can be quickly released to the external cable by the connector. Depending on the position of the various elements mounted on the
It is possible to obtain an excellent heat radiation effect of suppressing the temperature rise of the control arithmetic element. Therefore, the operation of the control arithmetic element becomes unstable due to the temperature rise, and the element is reliably prevented from being damaged without taking any special heat radiation measures such as forced cooling of the inside of the case by blowing air or a special radiation fin. Therefore, it is possible to eliminate an increase in cost for heat dissipation measures.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a vehicle-mounted electronic unit according to the present invention.

FIG. 2 is a longitudinal sectional view of the vehicle-mounted electronic unit in FIG. 2;

FIG. 3 is a longitudinal sectional view of a conventional vehicle-mounted electronic unit.

FIG. 4 is an exploded perspective view of the vehicle-mounted electronic unit in FIG. 3;

[Explanation of symbols]

 Reference Signs List 21 vehicle-mounted electronic unit 23 board unit 24 unit case 25 relay (drive element) 26 power transistor (drive element) 28 CPU (control operation element) 29 connector for external connection 30 printed circuit board 30a upper area 30b lower area 31 terminal Holder 32 Connection terminal 33 Upper case 34 Lower case 36 Connector connection opening

Claims (1)

[Claims] 1. A driving element such as a relay which generates a large amount of heat and a driving element
A board unit in which a control arithmetic element, such as a PU, which is vulnerable to temperature rise and a connector for external connection are mounted on a single printed circuit board; and the board unit accommodates the board unit and the connector on the board unit accommodates the external unit. A unit case provided with a connector connection opening that enables connection of a connection wire from a vehicle, and an in-vehicle electronic unit mounted on a vehicle, wherein: The on-vehicle electronic unit, wherein each element and the connector are arranged such that a region where the control arithmetic element is arranged is separated by the connector.