JPH0720348Y2 - Waste gate actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a waste gate actuator for driving a supercharging pressure control valve (waste gate valve) of a turbocharger, and more specifically to a vibration of a diaphragm. The present invention relates to the structure of the actuator having improved durability.

[Prior art]

A waste gate actuator (hereinafter, also simply referred to as an actuator) for driving a waste gate valve of a turbocharger has a diaphragm 2 that divides the case 1 into a positive pressure chamber A and an atmosphere chamber B as shown in FIG. In addition, the diaphragm 2 has the first shell 3,
The second shell 4 is fixed and the rod 5 extended from the atmosphere chamber B to the outside is fixed.

Further, in the atmosphere chamber, a spring 61 for urging the diaphragm 2 upward on the side opposite to the rod side is arranged between the second shell 4 and the case 1.

Then, by pressing the positive pressure chamber A side to cause the rod 5 to respond via the diaphragm 2, the waste gate valve is driven.

In this actuator, the tip of the rod 5 is connected to the waste gate valve and mounted on the turbocharger.
Prepare for use. The shell and rod are made of steel plate or carbon steel having a large specific gravity.

By the way, since the actuator main body and the rod are pointed at different positions, the phases and amplitudes of the vibrations generated by the vibrations propagated from the turbocharger or the like during use are different. Therefore, the diaphragm that fixes the rod to the center may generate an amplitude difference that causes friction with the first shell and the second shell that are sandwiched from both sides on the surface that is perpendicular to the vibration direction. .

The friction between the two shells and the diaphragm may cause the diaphragm to wear and eventually be damaged.

Therefore, conventionally, a means has been proposed in which a guide bush is provided between the rod and the waste gate valve to forcibly suppress the vibration of the diaphragm system (Japanese Utility Model Laid-Open No. 59-92203). Further, a means for coating the shell with a low friction material such as Teflon in order to prevent abrasion between the diaphragm and the shell has been proposed (Japanese Utility Model Laid-Open No. 58-30072).

[Problems to be solved]

However, all of these measures are merely to increase the number of parts and increase the cost, and to slow the wear rate, and to prevent damage to the diaphragm itself sandwiched between the first shell and the second shell. It is not a fundamental solution.

Further, the diaphragm is sandwiched between the first shell and the second shell, and fixed by caulking together with the rod (Example 1, see FIG. 1). Therefore, they are in a relatively fixed state. Therefore, in the conventional shell using steel plate or carbon steel, the frictional force between the shell and the diaphragm is large, and the diaphragm is greatly worn and damaged.

Especially during long-term use, the above iron-based materials generate rust,
Friction between the shell and the diaphragm is promoted.

The present invention has been earnestly studied in order to deal with such a problem, and has focused on the natural frequency of a diaphragm-based object composed of a rod and a shell fixed to a diaphragm and also focused on the material of the shell.

That is, the present invention is intended to provide a waste gate actuator capable of preventing abrasion and damage of the diaphragm caused by friction with the shell diaphragm and improving durability of the diaphragm.

[Means for solving problems]

The present invention is directed to a case, a rubber diaphragm arranged to divide the case into a positive pressure chamber and an atmospheric chamber, a first shell provided on the positive pressure chamber side so as to sandwich the diaphragm, and an atmosphere. A second shell provided on the chamber side; a rod having one end caulked and fixed to the diaphragm and both shells and extending from the atmosphere chamber to the outside; and a rod interposed between the second shell and the case in the atmosphere chamber. , The diaphragm is composed of a spring for urging the diaphragm upward on the side opposite to the rod side, and the natural frequency of the diaphragm-based object composed of the shell and the rod arranged on the diaphragm is in the engine operating range of the internal combustion engine. Supercharging pressure control of an internal combustion engine, characterized in that it is located in a region higher than the primary frequency of the explosion and the first shell and the second shell are made of an aluminum alloy. For waste gate actuator.

In the present invention, the engine rotation range refers to the range from the engine speed in the idling state of the engine to the maximum engine speed that can be used as a vehicle. Further, the explosion primary frequency in the rotation range refers to the frequency of the primary component of vibration generated in the explosion process of the engine.

The inventors of the present invention have conducted various studies on the damage to the diaphragm as described above centering on the vibration mechanism, and have clarified the relationship between the natural frequency of the diaphragm-based object and the explosion primary frequency. Then, it was clarified that the resonance phenomenon occurs when the former is in the latter frequency range, which increases the friction between the shell and the diaphragm and has a great influence on the damage of the diaphragm.

Therefore, in order to prevent this resonance phenomenon, further studies are conducted.
Considering that the natural frequency is higher than the explosion primary frequency, we have reached the point of reducing the weight of the diaphragm system object.

Then, as a means for reducing the mass of the diaphragm system as described above, it is optimal to configure the shell (both the first shell and the second shell are made of aluminum alloy) unless otherwise specified. In addition, aluminum alloy is
As will be described later, the friction between the shell and the diaphragm is reduced, and it exerts a great effect on the wear and damage of the diaphragm.

In the present invention, the rod is made of aluminum alloy,
It can also be made of a lightweight alloy such as a magnesium alloy. Further, holes may be provided in the shell or rod to such an extent that the strength thereof is not adversely affected, so-called meat stealing is performed (FIGS. 2 and 3), and further, the rod may be a hollow member. Of course, it is also possible to use a light alloy and to carry out the above-mentioned meat stealing or to make a hollow material.

[Action and effect]

In the present invention, the natural frequency of the diaphragm system object is set to the higher frequency side than the explosion primary frequency. Therefore, the resonance phenomenon does not occur, and the amplitude difference of the diaphragm portion becomes very small as shown by the dotted line in FIG. 5 described later.

Therefore, the friction between the diaphragm and the shell is greatly reduced, the wear of the diaphragm is very small, and its damage is almost eliminated.

The shell is made of aluminum alloy. Therefore, even when used for a long period of time, the shell does not rust unlike the conventional iron-based materials. Therefore, there is no need to promote the above friction due to the generation of rust as in the past.

What is more important to note is that the shell is made of an aluminum alloy, so it does not damage the diaphragm because it fits well with the rubber diaphragm.

That is, as described above, the diaphragm is sandwiched by the first shell and the second shell from both sides thereof, but since both shells are made of aluminum alloy, they are relatively soft as compared with the conventional steel shell.

Therefore, when both shells, the diaphragm and the rod are caulked and fixed as described above, the shell fits well to the diaphragm and does not bite into the diaphragm strongly. Therefore, the diaphragm is not scratched.

Also, since it is well-known, there is little friction between the shell and the diaphragm during vibration, and there is no wear or damage to the diaphragm.

In addition, if only for the purpose of reducing the weight of the shell,
It is also conceivable to use a synthetic resin (Act.
(See Japanese Utility Model Publication No. 59-21036). However, when the above synthetic resin is used, there is a problem that the shell is warped and a gap is generated between the shell and the diaphragm as the distance from the crimped portion with the rod increases.

This is due to the strain when molding the synthetic resin and the strain when caulking and fixing to the rod, and is considered to be due to lack of rigidity. The occurrence of such warpage accelerates the wear of the diaphragm and eventually causes damage.

On the other hand, if the synthetic resin plate is made thick in order to avoid this warpage, there is a problem that creep will occur over time in the use environment and the holding portion of the shell will loosen. Therefore, it is optimal to use aluminum alloy to reduce the weight.

As described above, according to the present invention, it is possible to provide a waste gate actuator capable of preventing wear and damage of the diaphragm caused by friction between the shell and the diaphragm and improving the durability of the diaphragm.

[Embodiment] First Embodiment A waste gate actuator according to the present embodiment is
This will be described with reference to FIGS.

As shown in FIG. 1, the actuator of the present embodiment has a case 1, a rubber diaphragm 2 for partitioning the inside of the case 1 into a positive pressure chamber A and an atmosphere chamber B, and the diaphragm 2 so as to sandwich the diaphragm 2. The first shell 3 provided on the upper side (positive pressure chamber), the shell 4 provided on the lower side (atmosphere chamber), the diaphragm 2 and both shells 3 and 4 are caulked and fixed at the upper end, and the atmosphere chamber B
And a rod 5 extending from the outside to the outside.

In the atmosphere chamber B, a spring 61 is provided between the second shell 4 and the case 1 to urge the diaphragm 2 upward on the side opposite to the rod side.

The diaphragm 2 has its entire peripheral edge 21 fixed at an intermediate position of the case 1. Further, the positive pressure chamber A is provided with a nozzle 10 which communicates with a controller for controlling this actuator. Reference numeral 62 is a bracket, and 63 is a seal rubber.

The upper end 51 of the rod 5 penetrates through the central holes of the second shell 4, the diaphragm 2 and the first shell 3 and is fixed by caulking the end portion at the upper part of the first shell 3. There is. Reference numeral 52 is a bolt hole for connecting to the waste gate valve.

In this example, the first shell 3 and the second shell 4 are made of an aluminum alloy having a specific gravity of about 2.7, and the rod 5 is made of carbon steel.

Next, the relationship between the natural frequency, the primary explosion frequency, and the resonance phenomenon in this example will be described.

First, as described above, in the prior art, the shells (first shell, second shell) are steel plates and the rods are carbon steel. At this time, the shell mass W ₁ is 53.5g and the rod mass W ₂ is 46g.
The total mass Wa is 99.5 g.

By the way, the frequency of this vibration system is k, where the elastic modulus of the diaphragm is k, the mass of the diaphragm system is W, the length of the rod is L, and the vibration frequency is f. Is. Here, the gravitational acceleration g, the elastic modulus of the diaphragm k, and the rod length L are constant, so a constant And Can be expressed as

Then, when the natural frequency f ₁ in the case of the above-mentioned conventional technique was obtained by actual measurement, it was f ₁ = 120 Hz.

On the other hand, the primary explosion frequency in the engine operating range was 140 Hz.

As is known from the above, in the case of the prior art, the natural frequency is 120 Hz, which is within 140 Hz of the explosion primary frequency (5th
Therefore, the resonance phenomenon with the primary component of the explosion will occur.

On the other hand, in the case of the present invention, since the shells 3 and 4 were made of the aluminum alloy and the rod 5 was made of carbon steel, the shell mass W ₃ was 18 g, the rod mass W ₄ was 46 g, and the total mass Wb = 64 g. is there. Then, the natural frequency at this time is f ₂ = 14 from the above equation.
It was 9.6 Hz and the measured value was about 150 Hz.

In other words, in this example, the natural frequency is higher than the explosion primary frequency.

FIG. 5 shows the relationship between the frequency and the amplitude of the diaphragm for the above-mentioned prior art and the present invention. E / in the figure
The G usage range is the engine rotation range.

As is known from the figure, when the aluminum alloy shell (dotted line) according to the present invention is used, the amplitude of the diaphragm is very small because the natural frequency is higher than the explosion primary frequency. I understand. On the contrary,
Since the natural frequency of the conventional steel shell (solid line) is within the range of the primary explosion frequency, it can be seen that the amplitude is very large.

In addition, in the above, also in the case of Examples described later, how much the total mass of the diaphragm system should be can be calculated as follows.

That is, in the prior art, the total mass of the diaphragm system is Wa,
If the natural frequency is f ₁ , the total mass in the present invention is Wb, and the natural frequency is f ₂ , then Wb <(f ₁ / f ₂ ) ² × Wa. And in the above example, Wa = 99.5g and f ₁ = 120, so f ₂
To make the region above the explosion primary frequency of 140 Hz,
Wb <(120/140) ² x 99.5 = 73g.

Therefore, when using the shell and rod having the same shape as the above-mentioned conventional technique, the total mass must be 73 g or less in the present invention. So in this example, 99.5
It is necessary to reduce the weight by -73 = 26.5g or more.

As is known from the above and FIG. 5, according to this example, since the natural frequency of the diaphragm-based object is higher than the primary frequency of the explosion, the difference in the amplitude of the diaphragm is very small. Therefore, the diaphragm 2 and the first shell 3, the second
The friction with the shell 4 is very small, and the diaphragm is hardly worn or damaged.

The first shell 3 and the second shell 4 are made of aluminum alloy. Therefore, during long-term use, rust does not occur unlike conventional steel shells,
There is no promotion of friction.

Further, since both shells 3 and 4 are made of an aluminum alloy, they fit well with the rubber diaphragm 2 and do not damage the diaphragm 2 as described above.

That is, the aluminum alloy is softer than conventional iron-based materials such as hard steel and carbon steel. Therefore, the diaphragm 2 is sandwiched between the shells 3 and 4, and these are connected to the rod 5
When caulked and fixed by, the first shell 3 and the second shell 4 fit well to the diaphragm 2 and do not bite strongly into the diaphragm 2. Therefore, the diaphragm 2 is not scratched.

In addition, since they are well compatible with each other, there is little friction between the first shell 3, the second shell 4 and the diaphragm 2 even during vibration,
The diaphragm 2 is not worn or damaged.

As described above, according to this example, the specific natural vibration region is set and the aluminum alloy shell makes it possible to reduce friction between the shell and the diaphragm very much and improve the durability of the diaphragm.

Second Embodiment In this embodiment, as shown in FIGS. 2 and 3, in the first embodiment, the upper and lower first shells 3 and second shells 4 are stolen to reduce the weight. This figure shows a cross section and a plan view of the first shell 3. The first shell 3 is in the shape of a deep dish as in the conventional case, and the bottom has a circular convex portion 31 formed around about half the radius, and a hole for fixing the rod 5 in the central portion. Has 33.

Further, six circular holes 32 are formed along the circular convex portion 31 to reduce the weight.

According to this example, since the circular holes 32 are provided in both the shells, the compatibility between the two shells and the diaphragm is further improved as compared with the case of the first embodiment. Therefore, the durability of the diaphragm is further improved. Further, the same effect as that of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a waste gate actuator showing a first embodiment of the present invention, FIGS. 2 and 3 are shells shown in a second embodiment, and FIG. 2 is a line AA of FIG. FIG. 3 is a sectional view taken along the arrow, FIG. 3 is a plan view, and FIG. 4 is a diagram showing the relationship between the frequency and the amplitude of the diaphragm portion in the first embodiment. 1 ... Case, 2 ... Diaphragm, 3 ... First shell, 4 ...
… Second shell, 5 …… rod, 32 …… round hole,

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Claims (2)

[Scope of utility model registration request] 1. A case, a rubber diaphragm arranged to divide the inside of the case into a positive pressure chamber and an atmosphere chamber, and a first shell provided on the positive pressure chamber side so as to sandwich the diaphragm. A second shell provided on the atmosphere chamber side, a rod having one end caulked and fixed to the diaphragm and both shells and extending from the atmosphere chamber to the outside, and interposed between the second shell and the case in the atmosphere chamber. , The diaphragm is composed of a spring for urging the diaphragm upward on the side opposite to the rod side, and the natural frequency of the diaphragm-based object composed of the shell and the rod arranged on the diaphragm is in the engine operating range of the internal combustion engine. Supercharging pressure control of an internal combustion engine, characterized in that it is located in a region higher than the primary frequency of the explosion and the first shell and the second shell are made of an aluminum alloy. Waste gate actuator. 2. The waste gate actuator according to claim 1, wherein the shell has holes.