JPH0745921Y2 - Flat resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of Invention] (Field of Industrial Application) The present invention relates to improvement of flat resistance in which a plurality of unit resistances are printed on a flat electrically insulating substrate.

(Prior Art) A blower for an air conditioner for a vehicle is provided with a fan in a fan scroll, and the fan is connected to a fan motor.
The rotation speed of the fan motor is controlled by the blower control device.

This blower control device connects a plurality of resistances having a predetermined resistance value in series and changes the total resistance value of the resistances to change the voltage applied to the fan motor to change the rotation speed of the fan motor. For example, the control is performed in multiple stages such as high speed rotation, medium speed rotation, and low speed rotation.

A conventional air-blowing control device consists of a resistance wound in a coil shape, which is installed in the air passage of an automobile air conditioner, especially in the air passage near the outlet of an intake unit, and radiates from the resistance. The Joule heat is quickly removed by the air flowing through the air passage.

However, in the air flow control device including the coiled resistance, the air resistance is large and the air flow flowing in the air passage is obstructed, and noise such as wind noise is generated. However, there is a problem that it is not preferable under a situation where there is a strong demand for a large air volume and quietness in the passenger compartment.

Therefore, as shown in FIGS. 8 and 9, a flat resistance FR is proposed in which a plurality of unit resistances R ₁ , R ₂ , and R ₃ are printed on the flat electrically insulating substrate 1 so as to be connected in series. . Since this flat resistance FR has a flat structure as a whole, it has good heat dissipation of Joule heat,
Because it has the characteristics of low ventilation resistance and low noise,
It has been widely used in recent years.

In the flat resistance FR shown in FIG. 8, a support frame 2 made of synthetic resin is attached to the outer periphery of an electrically insulating substrate 1. One end of the sub-harness 3 is connected to the terminals T _{1 to} T ₄ of each unit resistance R _{1 to} R ₃ , and the other end of the sub-harness 3 is connected to the coupler 4 which is separate from the support frame 2. Has been done. The coupler 4 is connected to a power supply coupler 6 on the vehicle side and supplies power to the terminals T _{1 to} T ₄ .

Even in the flat resistance FR shown in FIG. 9, the supporting frame 2 is attached to the outer periphery of the electrically insulating substrate 1, and the supporting frame 2 has an end portion of the electrically insulating substrate 1. Is formed with a head portion 5 into which is pressed and a coupler port 4a into which a power feeding coupler is attached. This coupler mouth
The coupler 4 is composed of 4a and the terminal T, and by connecting the feeding coupler 6 to the coupler 4, each of the T _{1 to} T ₄ and the terminal in the feeding coupler are directly connected. (See Japanese Utility Model Laid-Open No. 62-100, 211).

(Problems to be solved by the device) However, in the flat resistance FR shown in FIG. 8, since the support frame 2 and the coupler 4 are connected via the sub-harness 3, the mounting process of the sub-harness 3 is omitted. It was necessary and there was a problem that the assembly work of the flat resistance FR becomes complicated. Furthermore, because of such problems, there is a limit to cost reduction. Moreover, after the coupler 4 and the power supply coupler 6 are connected, it is necessary to fix the coupler 4 to the vehicle body panel or the like in order to prevent the rattling of this portion, which hinders the improvement of the assembling work.

On the other hand, the flat resistance FR shown in FIG. 9 can solve the above-mentioned problems. However, in this flat resistance FR, since the electrically insulating substrate 1 is only press-fitted into the head portion 5, when the power feeding coupler 6 is mounted on the coupler 4 of the support frame 2, the substrate is pressed by the pushing force of the power feeding coupler 6. There is a possibility that 1 may rattle and fall out of the support frame 2, or that the electrical connection between the terminals T _{1 to} T ₄ and the power supply coupler 6 may be incomplete.

The present invention has been made to solve the problems associated with the above-mentioned conventional techniques, and can be easily assembled, and further,
An object of the present invention is to provide a flat resistance capable of preventing the electrically insulating substrate from coming off or rattling when connecting a power feeding coupler.

[Structure of the Invention] (Means for Solving the Problems) The present invention for achieving the above-mentioned object is a flat electrically insulating substrate printed so that a plurality of resistances are connected in series, and this electrically insulating substrate. A support frame to which a board is attached, and a coupler port to which a power supply coupler connected to an external power source is mounted is formed in the support frame, and a terminal directly connected to the power supply coupler is provided on the electrically insulating substrate. In a flat resistance provided, a first engaging member is formed on the electrically insulating substrate, and a second engaging member that engages with the first engaging member is formed on the support frame,
The flat resistance constitutes a slip-out prevention mechanism for preventing the electric insulating substrate from slipping out by these engaging members.

(Operation) In the present invention thus configured, when the electrically insulating substrate is attached to the supporting frame, the first engaging member formed on the substrate and the second engaging member formed on the supporting frame are provided. Engage with each other to form a disengagement prevention mechanism. When the power feeding coupler is attached to the coupler port of the support frame, the detachment prevention mechanism prevents the electrically insulating substrate from coming off.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an essential part showing an embodiment of the flat resistance according to the present invention, FIG. 2 is a front view showing an electrically insulating substrate of the same embodiment, and FIG. 3 is III of FIG. -A sectional view taken along the line III, and FIG. 4 is a sectional view taken along the line IV-IV in FIG.
FIG. 5 is a schematic view showing an example of a ventilation control device having a flat resistance of the same embodiment, and FIG. 6 is a schematic perspective view showing a main part of FIG. 5 and shown in FIGS. The same members as the members are designated by the same reference numerals, and the description thereof will be partially omitted.

First, the blower control device having the flat resistance FR of this embodiment will be outlined.

As shown in FIG. 5, the base line L of the blower control device 7 is connected to one end of the battery B of the vehicle and drives the fan f of the blower fan via the current fuse F ₃ of the air conditioner for the vehicle. Connected with. The fan motor M is connected to the fan switch SW via a flat resistance FR having resistance R (general term of unit resistances R _{1 to} R ₃ ).

The fan switch SW is a terminal T (a general term for terminals T _{1 to} T ₄ ) that determines the rotation speed of the fan motor M by sliding the mover K, for example, a high speed terminal T ₁ (hereinafter referred to as HI terminal), Medium-high speed terminal T ₂ (hereafter MH terminal), medium-low speed terminal T ₃
(Hereinafter referred to as ML terminal) and low speed terminal T ₄ (hereinafter referred to as Lo terminal) are appropriately selected to change the rotation speed of the fan motor M in multiple stages.

In the flat resistance FR, as shown in FIG. 1, the supporting frame 2 is attached to the outer periphery of the electrically insulating substrate 1, and the end portion of the electrically insulating substrate 1 is press-fitted into the supporting frame 2. The head 5 and the coupler port 4a to which the power feeding coupler is attached are formed. The coupler 4 is composed of the coupler port 4a and the terminal T. By connecting the power feeding coupler 6 to the coupler 4, each of the T _{1 to} T ₄ and the terminals in the power feeding coupler are directly connected to feed power to the terminal T.

As shown in FIG. 2, the electrically insulating substrate 1 is composed of a so-called enamel plate in which a heat-resistant insulating layer is glazed on the peripheral surface of an iron plate, and a main body on which a plurality of unit resistances R _{1 to} R ₃ are printed. It has a portion 1a and a base portion 1b corresponding to the shape of the terminal T. On both sides of the base 1b, stopper pieces 11, 11 corresponding to a first engaging member that is flush with the substrate 1 are formed. The resistance R is covered and protected by a heat resistant insulating layer such as glass.

On the other hand, in the head portion 5 of the support frame 2, as shown in FIGS. 1, 3, and 4, four groove holes 10 are formed, and the terminal holes T ₁ to Each T ₄ is inserted.
As shown in FIG. 3, the slot 10 of the portion through which the stopper piece 11 is inserted has a width slightly larger than the thickness of the substrate 1, but the other portions are as shown in FIG. In addition, it is formed to have a width slightly smaller than the thickness of the substrate 1, and it is designed to be in close contact with both sides of the inserted substrate 1 and to sandwich it.

Further, in the support frame 2, as shown in FIGS. 1 and 3, a tongue piece 12 corresponding to a second engaging member inclined in the insertion direction of the substrate 1 is provided.
Are formed. The tip of the tongue piece 12 is located on the extension line of the slot hole 10 and has a step 13 for ensuring engagement with the stopper piece 11.

As shown in FIGS. 1 and 2, the resistance R is set so that the resistance values of the unit resistances R _{1 to} R ₃ become predetermined values.
The resistance member is printed in a predetermined pattern, and in the illustrated embodiment, the resistance member forming the terminal T is also printed integrally with the pattern. Then, this is baked and fixed.

A unit resistance R _{1 connected} to the HI terminal T ₁ is provided with a first thermal fuse F _{1 which} is blown by abnormal heat generation when the motor is locked. This first thermal fuse F ₁ is
A break is formed in a part of the resistance circuit formed on the substrate 1, and the break is welded so as to electrically connect the break, and the resistance R abnormally generates heat as when the fan motor M is motor locked. Then, the heat blows off and the power supply to the fan motor M is cut off.

Further, the unit resistance R ₂ is smaller than the cross-sectional area of the resistance member forming the unit resistance R ₁ , and the unit resistance R ₃ is smaller than the cross-sectional area of the resistance member forming the unit resistance R ₂ . This unit resistance R ₃ also has a second structure constructed in the same manner as the first thermal fuse F ₁ .
A thermal fuse F ₂ is provided.

Since the resistance member having a small cross-sectional area has an increased resistance value per unit length, the unit resistance R ₃ having the predetermined resistance value has a length shorter than the length of the other unit resistances R ₁ and R _2. It is configured. As a result, the degree of freedom in considering the print space and print pattern arrangement of the circuit of the resistance R on the substrate 1 is improved, and the flat resistance FR as a whole can be downsized. Further, providing the unit resistance second temperature units resistance R ₃ spaced relative to R ₁ fuse F _2, improved responsiveness to abnormal heat generation of the resistance R on the substrate 1,
It will be excellent in safety.

The unit resistance R ₃ has a small cross-sectional area. This is because in an air conditioner for an automobile, a low speed rotation is used for the longest time, and it is desired to ensure safety at the low speed rotation. Therefore, the cross-sectional area of the unit resistance R ₃ is reduced, and the second thermal fuse F ₂ is provided there to ensure safety.

In particular, as shown in Fig. 6, the flat resistance FR
Is provided in the fan scroll 8 of the intake unit in the vehicle air conditioner. In other words, the support frame 2 of the flat resistance FR is fan scroll 8
It is fixed to the bottom wall 8a of the fan with screws or the like so that the substrate 1 projects into the air passage 9 of the fan scroll 8.

Next, the operation will be described.

A case where the base portion 1b of the electrically insulating substrate 1 is inserted into the slot 10 of the support frame 2 to assemble the flat resistance FR will be described.

As the substrate 1 is inserted into the slot 10, the tongue piece 12 is pressed by the stopper piece 11 and elastically deforms. And the substrate 1
When the stopper piece 11 is inserted to the predetermined position,
The tongue piece 12 returns to the initial state as it goes over the tip end of the tongue piece 13 and the stopper piece 11 and the tongue piece 12 are engaged with each other to complete the assembly of the flat resistance FR.

In the flat resistance FR thus assembled, the support frame 2 is fixed to the bottom wall 8a of the fan scroll 8 with screws or the like.

When the power supply coupler 6 is attached to the flat resistance FR coupler 4, the pressing force of the power supply coupler 6 is
Although it is applied to the substrate 1 via the terminal T, the stopper piece 11 and the step portion 13 of the tongue piece 12 engage with each other, and
Is inclined, even if the above-mentioned force acts on the substrate 1, the substrate 1 will not rattle and will not come off from the support frame 2.

As described above, in the above-mentioned embodiment, the electrically insulating substrate is formed by both the stopper piece 11 as the engaging member formed on the substrate 1 and the tongue piece 12 as the engaging member formed on the support frame 2. Drop-out prevention mechanism that prevents slipping or rattling of 1
Although 14 is configured, the slip-off prevention mechanism 14 of the present invention is not limited to the illustrated shape. For example, as shown in FIGS. 7 (A) and 7 (B), a cut-and-raised portion 15 or a boss 16 as a first engaging member is formed on the substrate 1 to support the support frame 2
A protrusion, a hole, a claw (not shown) or the like as a second engaging member that engages with the first engaging member 15 (16) is formed in the above, and the disengagement prevention mechanism 14 is formed by these both engaging members. It may be configured.

[Effects of the Invention] As described above, the flat resistance of the present invention forms the first engaging member on the electrically insulating substrate, and
Since the second engagement member that engages with the first engagement member is formed on the support frame, and the engagement preventing mechanism that prevents the electrically insulating substrate from coming off is configured by these both engagement members, the power supply coupler is flat. When connecting to the resistance, it is possible to completely prevent the electrically insulating substrate from coming off or rattling.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the flat resistance according to the present invention, FIG. 2 is a front view showing an electrically insulating substrate of the same embodiment, and FIG. 3 is III of FIG. -A sectional view taken along the line III, and FIG. 4 is a sectional view taken along the line IV-IV in FIG.
FIG. 5 is a schematic view showing an example of a ventilation control device having a flat resistance of the same embodiment, and FIG. 6 is a schematic perspective view showing a main part of FIG. 5, and FIG. 7 (A), ( B) is
FIG. 8 is a perspective view showing an electrically insulating substrate according to another embodiment of the present invention, and FIGS. 8 and 9 are a perspective view showing a conventional flat resistance and a sectional view of an essential part. 1 ... Electrically insulating substrate, 2 ... Support frame, 4 ... Coupler, 4a ... Coupler port, 6 ... Feeding coupler, 11 ... Stopper piece (first engaging member), 12 ... Tongue piece ( the second engagement member) 13 ...... stepped portion, 14 ...... strain relief, FR ...... flat resistance, R _1, R _2, R ₃ ...... units resistance,
R: Resistance, T (T ₁ , T ₂ , T ₃ , T ₄ ) ... Terminal.

Claims (1)

[Scope of utility model registration request] 1. A flat electrically insulating substrate (1) printed so that a plurality of resistances (R) are connected in series, and a supporting frame (2) to which the electrically insulating substrate (1) is attached.
And a coupler port (4a) to which a power feeding coupler (6) connected to an external power source (B) is attached is formed in the support frame (2) and is directly connected to the power feeding coupler (6). In a flat resistance having a terminal (T) provided on the electrically insulating substrate (1), a first engaging member (11) is formed on the electrically insulating substrate (1), and the first engaging member is also provided. A second engagement member (12) that engages with (11) is formed on the support frame (2), and these engagement members (11, 12) prevent the electrically insulating substrate (1) from coming off. A flat resistance characterized by a slip-out prevention mechanism (14).