JPH0138842Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a hydraulic sensor that detects hydraulic pressure based on the amount of displacement of a contact lever that is in point contact with a diaphragm that is displaced in response to hydraulic pressure. be.

[Conventional technology]

Conventionally, this type of sensor has a structure shown in FIG. 2.

In the figure, a diaphragm 1 has a cap shape, and forms an oil chamber 3 by being fixed to a member 2 having a hydraulic pressure socket 2a by soldering. Displace. A contact stud 4a, which is crimped and fixed to the center of the contact lever 4, is in contact with the center of the bottom of the diaphragm 1. One end of the contact lever 4 is supported in a cantilever manner, and an electric contact 4b is provided at the other end.When the contact stud 4a is displaced in accordance with the displacement of the diaphragm 1, the electric contact 4b is amplified to approximately twice the displacement. and become displaced.

Above the contact lever 4, there is disposed a bimetal 5 which is supported in a cantilever manner and has an electric contact 5a at its free end, and a heater wire 6 is wound around the bimetal 5. The cantilever support of the contact lever 4 is performed by fixing one end of the contact lever 4 to a metal support frame 7, and the cantilever support of the bimetal 5 is achieved by fixing one end of the bimetal 5 to the support frame 7 with an insulating spacer. This is done by fixing via 8. The support frame 7 is secured to the gasket 1 by tightening the opening of the cap 9 to prevent dust and moisture.
It is integrated with the diaphragm 1 and the member 2 via the diaphragm 1 and the member 2.

The heater wire 6 has one end connected to the electrical contact 5a,
The other ends are respectively connected to terminals 11 provided on the cap 9, and the contact lever 4 is grounded via the support frame 7, diaphragm 1 and member 2 by attaching the sensor to, for example, a vehicle body.

With the above configuration, when the hydraulic pressure in the oil chamber 3 rises due to the hydraulic pressure P received from the hydraulic socket 2a and the diaphragm 1 is displaced, the contact lever 4 is also displaced, and its electrical contact 4b comes into contact with the electrical contact 5a of the bimetal 5. I come to do it. As a result, from the terminal 11 to the heater wire 6, the electrical contacts 5a, 4b, the contact lever 4, the support frame 7, the diaphragm 1, and the member 2.
Electric current flows through the vehicle body, and the heater wire 6 begins to generate heat. When the bimetal 5 is heated and deformed by the heat generated by the heater wire 6, its electrical contact 5a becomes separated from the electrical contact 4b of the contact lever 4. As a result, no current flows through the heater wire 6, so that the heater wire 6 no longer generates heat, and the bimetal 5 gradually cools down and returns to its original state. This restoration of the bimetal 5 brings the electrical contact 5a into contact with the electrical contact 4b of the contact lever 4 again, and the above-described operation is repeated.

The amount of displacement of the contact lever 4 is proportional to the oil pressure, and the time that the electric contact 5a is in contact with the electric contact 4b is proportional to the displacement position of the contact lever 4. Can detect oil pressure.

[Problem that the invention attempts to solve]

When the above-mentioned oil pressure sensor is attached to a vehicle body to monitor the oil pressure of the vehicle's hydraulic system, it is subjected to large external vibrations in a wide frequency range, and the contact lever 4 may resonate in a certain vibration range. When such resonance occurs, a phenomenon occurs in which the contact stud 4a of the contact lever 4 hits the surface of the diaphragm 1.

By the way, phosphor bronze for springs is used for the diaphragm 1, which can take a relatively large displacement in response to pressure, but phosphor bronze is relatively soft, and when the contact studs 4a hit the surface, abnormalities may occur in the contact area. cause wear. When such abnormal wear occurs, the effective displacement amount of the diaphragm relative to the oil pressure is reduced, and the reading of the oil pressure gauge based on the sensor signal becomes erroneous in the negative direction. Severe wear can destroy the diaphragm and cause oil leakage, and in the worst case scenario, it can cause the engine to seize.

Therefore, in view of the above-mentioned conventional problems, the present invention provides a hydraulic sensor that improves wear resistance and reduces hydraulic pressure indication errors without impairing the flexibility or ease of displacement of the diaphragm. The purpose is to

[Means for solving problems]

In order to achieve the above object, the hydraulic sensor developed according to the present invention consists of a diaphragm whose peripheral part is fixed by soldering to a member having a hydraulic socket, a diaphragm which is displaced by an amount corresponding to the magnitude of the hydraulic pressure, and a diaphragm whose one end is fixed to a member having a hydraulic socket by soldering. and a contact lever having a center portion in point contact with the diaphragm and an electric contact provided at the other end, the lever receiving the displacement of the diaphragm at the center point contact portion and using the one end as a base point. The oil pressure sensor detects oil pressure based on the amount of displacement of the electric contact at the other end of the contact lever, wherein the diaphragm is made of a material that is highly flexible and capable of large displacement. a first metal plating layer made of hard chrome plating with excellent wear resistance applied on the substrate, and a second metal plating layer with good solderability applied on the surface of the first metal plating layer. It is characterized by being constructed with a metal plating layer.

[Effect]

In the above configuration, the substrate of the diaphragm is made of a material that is highly flexible and capable of large displacements without impairing its flexibility or ease of displacement. Since the first metal plating layer is hard chrome plating, even if the contact lever vibrates due to external vibration and the surface of the diaphragm is struck by point contact,
The surface of the diaphragm does not wear out, and the displacement amount of the contact lever is prevented from changing to a value different from the expected value, and the occurrence of oil leakage due to breakage is prevented.

In addition, since a second metal plating layer with good solderability is further applied to the surface of the first metal plating layer, it is not necessary to provide a layer made of hard chrome plating, which generally has poor solderability. Therefore, the soldering of the diaphragm to the member having the hydraulic pressure socket is not impaired. Moreover, this second layer with good solderability is made of a plating layer and is extremely thin, so even if this second metal plating layer wears out at the point contact area, the amount of displacement of the contact lever will not change significantly. It does not disturb the detection amount.

〔Example〕

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

FIG. 1 shows the main parts of the oil pressure sensor according to the present invention. The diaphragm 1 includes a diaphragm base material 1a made of phosphor bronze for springs that can take a relatively large amount of displacement with respect to pressure, and a diaphragm base material 1a made of phosphor bronze for spring use, which has excellent wear resistance and has high hardness and a small coefficient of friction. For example, a first metal plating layer 1b such as hard chrome plating, and a second metal plating layer 1c such as tin plating having excellent solderability applied to the entire surface of the first metal plating layer 1b. It consists of.

In order to form the oil chamber 3, the diaphragm 1 as described above is fitted into the member 2 having the hydraulic pressure socket 2a, and then solder 12 is applied between the diaphragm 1 and the member 2 to seal the oil.

Since the surface of the diaphragm 1 is a tin-plated layer, soldering for oil sealing can be easily performed. The sparrow layer has poor wear resistance, but
The layer thickness is extremely small, on the order of microns, and the lower layer of the tin plating layer is a hard chrome plating layer with excellent wear resistance.
The wear due to the pounding phenomenon is less than the level of the suzmetuki, and there is almost no error in the oil pressure indication.

It is also possible to apply hard chrome plating only to the part of the diaphragm 1 that contacts the contact stud 4a, but such partial plating requires a special plating jig and makes the plating work extremely troublesome. , resulting in high costs due to poor productivity.
In this regard, the present invention uses two layers, a hard chrome plating layer and a tin plating layer, and since both layers are applied over the entire surface of the base material, it is easy to work with and is advantageous in terms of cost. be.

[Effect of idea]

As explained above, according to the present invention, the substrate of the diaphragm is made of a material that is highly flexible and capable of large displacements, so that flexibility and ease of displacement are not impaired.

In addition, since the first metal plating layer made of hard chrome plating with excellent wear resistance is applied to the substrate, the diaphragm may wear out and cause a large hydraulic pressure reading error, or break and cause oil leakage. There is nothing to do.

Furthermore, since the second metal plating layer with good solderability is applied to the surface of the first metal plating layer,
The diaphragm can be soldered well. In addition,
The second layer for improving solderability is made of a plating layer and is extremely thin, so even if this second metal plating layer wears out, the hydraulic pressure indication will not be significantly deviated.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of a hydraulic pressure sensor according to the present invention, and FIG. 2 is a cross-sectional view showing the overall structure of a general hydraulic sensor. 1...Diaphragm, 1a...Diaphragm,
1b...First metal plating layer (hard chrome plating), 1c...Second metal plating layer (stain plating), 4...Contact lever.

Claims (1)

[Claims for Utility Model Registration] A diaphragm whose peripheral portion is fixed by soldering to a member having a hydraulic socket, which is displaced by an amount corresponding to the magnitude of the hydraulic pressure, one end of which is supported in a cantilever manner, and whose central portion is A contact lever that is in point contact with a diaphragm and has an electric contact at the other end, and is displaced from the one end as a base point by receiving displacement of the diaphragm at a central point contact part. The oil pressure sensor detects oil pressure based on the amount of displacement of the electric contact at the end, and the diaphragm is formed of a substrate made of a material that is highly flexible and capable of large displacement, and a substrate formed on the substrate. It is composed of a first metal plating layer made of hard chrome plating with excellent wear resistance, and a second metal plating layer with good solderability applied to the surface of the first metal plating layer. Features oil pressure sensor.