JPH0443779Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to an air flow meter that is mainly installed in a vehicle engine and measures the amount of air taken into the engine, and in particular relates to an air flow meter that is installed in a vehicle engine and measures the amount of air taken into the engine. This invention relates to a holding device.

[Conventional technology]

In recent years, vehicle engines equipped with electronically controlled fuel injection devices are generally known. This electronically controlled fuel injection system basically measures the amount of air taken into the engine using an air flow meter, and calculates the amount of fuel according to this amount of intake air using a control device such as a computer.
The calculated amount of fuel is supplied to the engine by the fuel injection valve.

As one of the air flow meters mentioned above, a plate-shaped vane is arranged in the intake passage facing the flow of intake air and receives a force in the direction of completely closing the intake passage. There is a vane type air flow meter that is displaced and generates an electrical signal from a potentiometer according to this displacement.

The potentiometer of this vane-type air flow meter is installed inside a case set outside the intake passage, and inside this case there is also a potentiometer in the direction of fully closing the intake passage with respect to the vane as described above. A return spring is provided that exerts a return force on. This return spring is usually composed of a spiral leaf spring, one end of which is connected to a member that rotates in accordance with the rotation of the vane, and the other end of which is a resin-made leaf spring that is fixed by a fixing device inside the case. It is held on the inner peripheral wall of an annular spring case. (Reference: Jitsukiaki
56-6894).

[Problem that the invention attempts to solve]

However, in recent years, there has been an increasing demand for improved mountability in vehicles, especially for automobile engines, and the conventional spring cases as mentioned above are made of resin, so the strength has not been improved. Due to this problem, it is impossible to reduce the wall thickness of the spring case, and therefore the spring case occupies a large volume within the case, which is one of the factors that prevents miniaturization of the case. For this reason, the configuration is disadvantageous in terms of reducing the size of the case and, by extension, reducing the size of the air flow meter to improve its mountability on a vehicle.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a return spring holding device for an air flow meter that can reduce the size of the air flow meter, and to improve the ease with which the air flow meter can be mounted on a vehicle.

[Means for solving problems]

In order to solve the above problems, in the present invention, a plate-shaped vane is rotatably disposed in the intake passage facing the intake air flow, and a plate-shaped vane is arranged outside the intake passage and has a spiral shape. A return spring holding device for an air flow meter biased by a return spring made of a leaf spring, which is made of a thin steel plate, has a height approximately equal to the plate width of the return spring, and houses the return spring therein. a cylindrical part; a flange part made of the same thin steel plate as the cylindrical part and extending toward the outer circumference from one end of the cylindrical part; and an uneven locking part formed along the outer periphery of the flange part; and a protrusion that is formed by protruding the steel plate on the cylindrical wall surface of the cylindrical part toward the inside of the cylindrical part and that fits into a fitting hole formed at one end on the outer peripheral side of the return spring. Adopts the characteristic technical means of air flow meter return spring holding device.

[Effect]

According to the above configuration of the present invention, the holding device in which the return spring is accommodated and held is formed of a sheet metal component made of a thin steel plate. Therefore, compared to conventional resins, the wall thickness can be made thinner while maintaining strength, and miniaturization can be achieved.

Furthermore, the protrusion that fits into the fitting hole of the return spring and holds the return spring inside the cylindrical portion is formed by protruding a steel plate on the cylindrical wall surface of the cylindrical portion toward the inside of the cylindrical portion. Therefore, compared to conventional resins,
The protrusion has been made smaller while maintaining the necessary strength, and there is no problem such as when the protrusion gets stuck when assembling the return spring. Further, since this protrusion is formed integrally with the steel plate forming the cylindrical portion, no separate part is required for holding and fixing the return spring. Therefore, by making the projection smaller and reducing the number of parts, not only the overall size is reduced, but also the ease of assembling the return spring inside the cylindrical portion is improved.

Additionally, since the protrusions are made of steel, there is less wear compared to conventional resin, and durability is improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

1a and 1b are diagrams showing the configuration of the return spring holding device and the return spring held by the holding device of this embodiment, and FIG. 2 is an enlarged cross-sectional view taken along the line A-A in FIG. 1a. 3 is a diagram showing the external appearance of the air flow meter, and FIG. 4 is a diagram showing the configuration inside the case of the air flow meter of FIG. 3 equipped with the return spring holding device shown in FIG. 1. It is.

As shown in FIG. 3, a case 3 is integrally formed outside the intake passage of the housing 2 of the vane type air flow meter 1. Reference numeral 4 denotes a cover that covers the case 3, and a plate-shaped vane (not shown) is provided in the intake passageway, facing the flow direction of the intake air, and rotating in the flow direction of the intake air according to the amount of intake air.

The inside of the case 3 has a structure as shown in FIG. 4, in which one end of the vane is connected and a rotation shaft 5 is rotatably supported with respect to the housing 2.
is set so as to penetrate through the housing 2 and protrude into the case 3. A rotating member 7, which constitutes a component of a potentiometer 6 set in the case 3, is connected to an end of the rotating shaft 5, and the rotating member 7 rotates in accordance with the rotation of the vane. . The rotating member 7 is provided with a slider 8 made of a conductive material that is displaced in the radial direction according to the rotation of the rotating member 7. The slider 8 is attached to the housing 1 on the bottom of the case 3 by screws 9. It slides on the circuit board 11 mounted and fixed on the support plate 10 which is fastened and fixed. The circuit board 11 is made of an insulating material such as ceramic, and has a printed resistance pattern whose resistance value changes along the direction in which the slider 8 is displaced.

Moreover, one end is fixed to the rotating shaft 5 between the rotating member 5 and the support plate 10 and the bottom surface of the case 3, and the vane applies a return force to the vane in the rotating direction to fully close the intake passage. A return spring 12 made of a spiral leaf spring is provided, and the return spring 12 is housed in a spring case 13, which will be described later, and serves as a return spring holding device. Retained. and,
This spring case 13 is fixed to the bottom surface of the case 3 together with the support plate 10 by a screw 9 that fastens and fixes the support plate 10 to the bottom surface of the case 3.
4, and this spring case 1
3, the return force applied to the vane by the return spring 12 is set.

Therefore, the potentiometer 6 basically includes a rotating member 7, a slider 8, a support plate 10, a circuit board 11, a return spring 12, a spring case 13, and a case stop 14.

In addition, the intake sensor 15 is installed in the case 3.
The case 3 is set so as to penetrate through the bottom surface of the case 3 and protrude into the intake passage, and is pressed and fixed to the bottom surface of the case 3 by a support plate 10. Furthermore, a plurality of terminals 17 are set on the inner side wall surface of the case 3 to be connected to a plurality of pins in a connector 16 set on the outer side wall surface of the case 3. Terminal 1
7 is connected to the slider 8, the resistance pattern of the circuit board 11, the intake temperature sensor 15, and contacts 18 and 19. Note that the contacts 18 and 19 are opened by an arm 20 set on the rotating member 7 only when the vane is fully closed, and serve as a fuel pump relay switch that turns off the fuel pump (not shown).
8 is provided on the conductive leaf spring. In order to close the contacts 18 and 19 even in a small intake air amount state, an additional spring 21 is provided on the support plate 10, which is a spiral leaf spring that weakens the return force of the return spring 12 in a small rotation angle range from the fully closed state of the vane. It is held by a protrusion 22 consisting of a part, and an additional spring 21
One end of the rotary member 7 is set to abut against the rotary member 7 within the rotation angle range.

Therefore, an analog signal corresponding to the intake air amount and an intake air temperature signal are taken out from the terminal 17 and transmitted from the pins of the connector 16 to a control device (not shown) comprising a computer or the like via a signal line (not shown). Furthermore, the opening/closing of the contacts 18 and 19 is transmitted to the fuel pump relay via the terminal 17 and the pin of the connector 16.

Next, the structure of the spring case 13 that houses the return spring 12 and holds one end thereof will be described using FIGS. 1a and 1b and FIG. 2.

In FIG. 1a, as described above, the return spring 12 is housed in the spring case 13, and one end is held by the spring case 13. The other end of the return spring 12 is molded and fixed to a connecting member 23 made of resin and connected to the rotating shaft 7.

The spring case 13 is made of a thin steel plate, and the steel plate used is, for example, a cold rolled steel plate. By constructing the steel plate in this manner, the desired strength can be sufficiently obtained even if the wall thickness is made thin. Therefore, the spring case is sufficiently smaller than the conventional resin spring case.

The spring case 13 includes a cylindrical portion 131 having a height comparable to the plate width of the return spring 12, and this cylindrical portion 13.
A flange portion 13 extending in the outer circumferential direction from one end of 1
For example, the cylindrical portion 131 is formed by pressing an annular flat steel plate.

Further, a sawtooth-shaped locking portion 133 is formed along the entire outer circumference of the flange portion 132 and engages with the case stopper 14 . This serrated locking portion 133 is also formed by cutting, for example, with a press or the like.

The cylindrical portion 131 is formed so as to be bent from the end opposite to the end where the flange portion 132 is formed along the inner periphery of the cylindrical portion 131 with a slight gap therebetween. A guide plate 134 is integrally provided. Note that the height of this guide plate 134 is approximately the same as the height of the cylindrical portion 131, or slightly lower.

Further, in the cylindrical portion 131 that is slightly spaced apart from the portion of the cylindrical portion 131 where the guide plate 134 is formed, a circular shape, as shown in FIG. A communication hole 135 and a cylindrical protrusion 136 that protrudes inside the cylindrical portion 131 are provided along the periphery of the communication hole 135 .

A circular fitting hole 121 is formed at one end of the return spring 12 to fit the projection 136 of the spring case 13 having the above structure, and the return spring 12 is held in the spring case 13 having the above structure. The return spring 12 is positioned between the guide plate 134 and the inner circumference of the cylindrical portion 131 to guide it, and the fitting hole 121 of the return spring 12 and the cylindrical portion 131 are connected to each other.
This is done by fitting the protrusions 136.

Protrusion 13 in spring case 131 with the above configuration
6 is a burring process, that is, a cylindrical part 131
This is because the steel plate of the cylindrical portion 131 protrudes inside the cylindrical portion 131 along the periphery of the communication hole 135 by forming a communication hole 135 that communicates from the outside to the inside. , the formation of the protrusion 136 is extremely simple.

Further, in the spring case 13, the protrusion 136 that fits into the fitting hole 121 of the return spring 12 is connected to the cylindrical portion 131.
Even if the tensile force of the return spring 12 due to the rotation of the vane is repeatedly applied to the protrusion 136, the protrusion 136 suffers little wear, and therefore the protrusion 136 can last for a sufficiently long period of time. It is durable and has greater durability than conventional resin products. The same can be said of the locking portion 133 that engages with the case stopper 14.

In the above embodiment, the communication hole 135 is circular and the protrusion 136 is formed in a cylindrical shape. However, the communication hole 135 may be formed in a triangular or square shape and the protrusion 136 is formed in a triangular or quadrangular prism shape. .
In this case, the fitting hole 121 formed at one end of the return spring 12 is preferably formed to match the shape of the projection 136.

[Effect of idea]

As described above, according to the present invention, the holding device in which the return spring is housed and held is made of a thin steel plate, and the protrusion into which the fitting hole of the return spring fits is also formed by protruding the steel plate inward. Compared to conventional resins, the holding device can be made smaller while maintaining the necessary strength.
As a result, the air flow meter to which this holding device is assembled can be downsized. Furthermore, since the projection is miniaturized and there is no increase in the number of parts, the work of assembling the return spring can be facilitated. moreover,
According to the present invention, since the protrusion is formed of a thin steel plate, it exhibits excellent abrasion resistance against friction with the return spring and can also improve durability.

[Brief explanation of the drawing]

FIGS. 1a and 1b are front and side views showing the configuration of a return spring holding device and the return spring held by the holding device according to an embodiment of the present invention, and FIG. An enlarged sectional view of section A, Figure 3 is an external view showing the external shape of the air flow meter, and Figure 4 is an enlarged sectional view of the air flow meter.
FIG. 4 is a configuration diagram showing the configuration inside the case of the air flow meter shown in FIG. 3 having the return spring holding device shown in FIG. 3; 11... Air flow meter, 2... Housing, 3... Case, 5... Rotating shaft, 6... Potentiometer, 7... Rotating member, 10... Support plate,
11... Circuit board, 12... Return spring, 13...
Spring case, 14... Case stop, 121... Fitting hole, 131... Cylindrical part, 132... Flange part, 133... Locking part, 134... Guide plate, 1
35...Communication hole, 136...Protrusion.

Claims (1)

[Claims for Utility Model Registration] (1) A plate-shaped vane rotatably disposed within the intake passage facing the intake air flow, and a return consisting of a spiral plate spring installed outside the intake passage. A return spring holding device for an air flow meter biased by a spring, comprising: a cylindrical portion made of a thin steel plate, having a height approximately equal to the plate width of the return spring, and accommodating the return spring therein; a flange portion made of the same thin steel plate as the cylindrical portion and extending toward the outer circumference from one end of the cylindrical portion; an uneven locking portion formed along the outer periphery of the flange portion; An air flow meter characterized in that the steel plate of the cylindrical wall surface is formed by protruding toward the inside of the cylindrical portion, and includes a projection that fits into a fitting hole formed at one end on the outer peripheral side of the return spring. return spring retainer. (2) The protrusion is formed by making the steel plate on the cylindrical wall surface of the cylindrical part protrude in a cylindrical shape toward the inside of the cylindrical part, and opening the tip of the cylindrical protrusion. A return spring holding device for an air flow meter according to claim 1, which is a registered utility model. (3) The cylindrical portion extends inward from the end opposite to the end where the flange portion is provided, and connects one outer peripheral end of the return spring with the inner peripheral wall of the cylindrical portion. A return spring holding device for an air flow meter according to claim 1, characterized in that the device includes a guide plate sandwiched therebetween.