JPH07208407A - Diaphragm type actuator - Google Patents

Abstract

PURPOSE:To improve heat radiation performance and assemblability by providing a non-circular cross-section in a part of an actuating rod and the central holes of the shapes corresponding to the non-circular cross-section and the circular cross-section of the actuating rod in an axial guide to make a non-split type which is fitted thereinto in the axial direction of the actuating rod. CONSTITUTION:An actuating rod 20 passes through the loose hole 25 of a lower casing 12 and is led to the outside of a casing 11, and a flat part 20c is formed in the outer end to constitute a non-circular cross-section, and the other is a circular cross-section. An axial guide 30 for slidably guiding the actuating rod 20 is provided in the casing 11, and a central hole 33a is formed therein, and the central hole 33a is constituted of a circular hole 33b corresponding to the actuating rod 20 of a circular cross-section and an expansion hole 3 corresponding to a flat part 20c. The axial guide 30 is non split type composed of one member, and a clearance (c) is provided between the circular hole 33b and the actuating rod 20 of circular cross-section, and a large gap is formed by the expansion hole 33c. Thereby, the heat radiation of a bearing part is improved, and the assembling of the actuating rod is improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an actuator having a rod connected to a diaphragm and performing work by displacement of the rod.

[0002]

2. Description of the Related Art This type of actuator is used, for example, as an actuator of a supercharger (turbocharger) of a vehicle. More specifically, it is used as an actuator for activating a waste gate valve when the engine rotates at a high speed and allowing a part of the exhaust gas of the engine to escape in front of the turbine chamber.

This actuator basically divides the inside of the casing into two chambers by a diaphragm, introduces the inlet pressure to the turbine into one chamber, and the pressure difference between the chamber and the other chamber open to the atmosphere reaches a predetermined value. When reached, the diaphragm and the actuation rod connected thereto are displaced to actuate the wastegate valve.

In this actuator, in order to prevent the diaphragm from being excessively deformed due to vibration of the vehicle, displacement of the waste gate valve, or the like, a bearing provided on a casing supports the operating rod. Conventionally, this bearing is composed of a pair of half bearings divided in the radial direction, and the pair of half bearings is pressed against the operating rod by an O-ring. This two-part structure of the bearing of the working rod was considered to be an indispensable structure for preventing excessive deformation of the diaphragm and absorbing vibration.

On the other hand, this actuator is placed in a high temperature environment called an engine room. Therefore, it is preferable that the heat dissipation is excellent, but the conventional two-divided type bearing is inferior from the viewpoint of heat dissipation because the structure is in close contact with the operating rod due to the elasticity of the O ring. So, conventionally,
It has been forced to use an expensive material having excellent heat dissipation and heat resistance. Further, the two-split bearing has a large frictional force because it is in close contact with the operating rod, and when the operating rod slides, abrasion powder is generated, and this abrasion powder adheres to the operating rod to allow smooth sliding. There was a problem of disappearing.

Further, the conventional two-divided type bearing has a problem that workability is poor when it is mounted on the outer periphery of the operating rod.

[0007]

SUMMARY OF THE INVENTION The present invention is structurally excellent in heat dissipation of the bearing portion of the operating rod, can be made of a material that is less expensive than conventional products, is excellent in assembling with the operating rod, and is excessively deformable of the diaphragm. The purpose is to obtain a diaphragm actuator that is comparable to conventional products in terms of prevention and vibration absorption.

[0008]

SUMMARY OF THE INVENTION The present invention comprises a casing; a diaphragm dividing the casing; an actuation rod coupled to the diaphragm; and a bearing retained in the casing for slidably guiding the actuation rod. In this type of diaphragm type actuator equipped with, focusing on the fact that the working rod of circular cross section has a non-circular cross section for connection at a part (generally the end), the bearing is The non-circular cross section and the center hole having a shape corresponding to the circular cross section are provided, and the non-divided shaft guide is fitted into the actuation rod in the axial direction of the actuation rod.

According to this structure, the center hole of the shaft guide is
Since it has a circular hole corresponding to the circular cross section of the operating rod and an expansion hole corresponding to the non-circular cross section of the operating rod, which is continuous with this circular hole, in the state of guiding the operating rod, In addition to the clearance between the circular hole and the circular cross section, a large clearance is secured by the expansion hole. Therefore, a shaft guide with excellent heat dissipation can be obtained,
Even if the shaft guide is formed from an inexpensive material that does not require high heat resistance, problems such as damage due to heat do not occur. This shaft guide is a non-divided type and can be assembled simply by inserting it into the actuation rod, so that it is excellent in assembling workability.

A clearance of about 0.1 to 0.3 mm is set between the circular hole of the central hole of the shaft guide and the circular cross section of the operating rod in order to avoid direct contact between the two. Is desirable. The working rod and the shaft guide are
Because of this clearance, there is no constant contact,
Wear powder is unlikely to occur, and even if it does,
Since it escapes to the expansion hole, it is unlikely to adhere to the operating rod. Further, since the expansion hole portion may be the minimum necessary, it is possible to prevent excessive deformation of the diaphragm.

The central hole of the shaft guide may have a closed shape or a part thereof may be opened. This actuator is particularly useful as an actuator placed in a high temperature environment, such as a turbocharger of a vehicle.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. This embodiment is used as an actuator for a wastegate valve of a turbocharger of a vehicle. The casing 11 is composed of a lower casing 12 fixed to the mounting base 10 and an upper casing 13 fixed to the lower casing 12. The peripheral edge of the metal diaphragm 14 is sandwiched between the lower casing 12 and the upper casing 13. It is fixed in place. The inside of the casing 11 is formed by the diaphragm 14 as shown in FIGS.
Closed working pressure chamber 15 and lower atmosphere release chamber 1
It is divided into 6 and 6. A conduit 17 for guiding the turbine inlet pressure of the turbocharger is opened in the working pressure chamber 15, and the atmosphere opening chamber 16 is communicated with the outside through a communication hole 18.

Above and below the center of the diaphragm 14 (front and back)
The retainer plates 21 and 22 are located on the base plate, and the retainer plates 21 and 22 and the diaphragm 14 are fixed to the one end portion of the actuating rod 20 by caulking and well-known fixing means such as screwing. That is, the operating rod 2
0 is displaced integrally with the diaphragm 14.

A compression spring 23 for urging the diaphragm 14 to move upward in FIGS. 1 and 2 is inserted in the atmosphere opening chamber 16 of the lower casing 12.
Is normally located at a rest position where the retainer plate 21 contacts the inner wall of the upper casing 13.

The operating rod 20 is guided to the outside of the casing 11 through the play hole 25 of the lower casing 12. This actuating rod 20 includes necessary bending portions 20a, 20
b, and a flat portion 20c is formed at the outer end portion thereof. The flat portion 20c is provided with a connection hole 20d for the interlocking arm with the wastegate valve. This flat part 2
0c constitutes a pair of non-circular cross-section portions projecting diametrically from the operation rod 20 having a circular cross section when the operation rod 20 is viewed in the axial direction (see FIGS. 3 and 4). Working rod 2
0 is a uniform circular cross section except for the flat portion 20c.

The casing 11 includes the operating rod 20.
A shaft guide 30 which is a feature of the present invention and which slidably guides is provided. The shaft guide 30 is fitted into the holding cup 31 and is inserted into the lower casing 12 while being covered with the cover plate 32.
The entire shaft guide 30, holding cup 31, and cover plate 32 are pressed against the bottom of the lower casing 12 by the compression spring 23.

3 and 5 show a first embodiment of the shaft guide 30. A center hole 33a is formed in the center of the shaft guide 30. This central hole 33a
Is a circular hole 33 corresponding to the operating rod 20 having a circular cross section.
b and the operating rod 20 continuous with the circular hole 33b.
And an expansion hole portion 33c corresponding to the flat portion 20c. The expansion holes 33c are formed on both sides of the circular hole 33b in the diametrical direction, and one of the expansion holes 33c is formed.
Reference character c'is configured as an open groove that reaches the outer circumference of the shaft guide 30 and opens the central hole 33a. An insertion groove 35 into which an O-ring 34 is fitted is formed on the outer periphery of the shaft guide 30 at the center in the thickness direction.

4 and 6 show a second embodiment of the shaft guide 30. This embodiment is an example in which the central hole 33a is formed as a closed curve without being opened. The other part is shown in FIG.
This is the same as the embodiment of FIG. 5, and the same parts are given the same reference numerals.

In each of the embodiments, the shaft guide 30 is a non-divided type composed of one member, and a clearance c is set between the circular hole 33b and the operating rod 20 having a circular cross section. This clearance c is, as described above,
It is preferably 0.1 to 0.3 mm. Further, the shaft guide 30 of the present invention only needs to have heat resistance at a polyacetal or polyamide level, and in addition, polyphenylene sulfide, phenol resin, PEI, PES, PEEK and the like can be used. Of course, additives for improving frictional characteristics, for example, graphite, MoS ₂ , PTFE, inorganic hard additives, fibers and the like may be added. In this embodiment, it is made of a fluororesin to which graphite or the like is added.

In the present actuator having the above structure, when the shaft guide 30 is set on the outer circumference of the operating rod 20, as shown in FIGS.
The ring 34 is fitted, and the flat portion 20c of the operating rod 20 is fitted into the expansion hole portion 33c and inserted into the shaft guide 30. Since the shaft guide 30 is made of one member, there is no difficulty in this insertion work. Axis guide 30 and O-ring 34
Is then fitted into the holding cup 31 and the cover plate 3
2 is set on the bottom of the lower casing 12. The O-ring 34 is provided in the holding cup 31 so that the shaft guide 30
When inserted together, it elastically contacts with the inner wall of the holding cup 31 to absorb vibration, or prevents generation of abnormal noise when the operating rod 20 changes direction.

In the set state of FIGS. 1 and 2, the shaft guide 3
3 between the central hole 33a and the actuating rod 20 in addition to the clearance c between the circular hole 33b and the expansion hole 33a.
A large gap is formed by c. Therefore, heat from the engine or the working rod 2 passes through this gap.
It is possible to efficiently dissipate the heat generated by the sliding between 0 and the central hole 33a. Further, since the clearance c is set between the circular hole portion 33b and the actuating rod 20 and there is no constant contact with the entire surface at all times, there is little possibility that abrasion powder is generated, and even if it is generated, Circular hole 3
Since it is discharged from 3b, it is unlikely to adhere to the operating rod 20. The vibration absorbing function is achieved by the shaft guide 30 and the O-ring 3.
4 can be obtained.

In the embodiment of FIGS. 3 and 5, the shaft guide 30 having a relatively elastic characteristic such as a fluororesin uses an O-ring 34 which is relatively strong (having a small inner diameter in the free state). In the free state, the inner diameter of the circular hole 33b and the width of the expansion hole 33c can be slightly reduced. Therefore, the inner diameter of the circular hole 33b in the free state of the shaft guide 30 is preferably determined in consideration of the diameter reduction due to the O-ring 34. In this case, in the reduced diameter state, the central hole 33a
The shape may be determined so that a part of the positive contact with the actuation rod 20 is positive. Even in this case, with respect to the assembling property, the heat radiation property, and the discharge of the abrasion powder, the same operational effects as described above can be expected, and further, a part of the center hole 33a is stronger and the operating rod 2 is stronger.
By touching 0, the shaft guide 30 and the O-ring 3
It is possible to expect a more excellent vibration absorbing property according to No. 4.

In the present actuator, when the pressure in the turbine inlet chamber exceeds a predetermined value, the diaphragm 14 and the operating rod 20 are displaced against the force of the compression spring 23, and the connecting hole 20.
The wastegate valve opens via the interlocking arm connected to d, and acts to release a part of the exhaust gas before the turbine chamber.

[0024]

As described above, the diaphragm type actuator of the present invention is excellent in heat dissipation of the bearing portion of the operating rod, is excellent in assembling with the operating rod, and is excellent in discharging of abrasion powder. Therefore, it is suitable as an actuator for equipment such as a turbocharger placed in a high temperature environment.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a diaphragm type actuator according to the present invention.

FIG. 2 is an external view of the same.

FIG. 3 is a plan view showing a first embodiment of the shaft guide used in the actuator of FIG.

FIG. 4 is a plan view showing a second embodiment of the shaft guide used in the actuator of FIG.

5 is a perspective view showing a tip end portion of the shaft guide and the operating rod of FIG. 3. FIG.

6 is a perspective view showing a tip portion of the shaft guide and the operating rod of FIG. 4. FIG.

[Explanation of symbols]

 11 Casing 14 Metal Diaphragm 15 Working Pressure Chamber 16 Atmosphere Opening Chamber 20 Working Rod 20c Flat Part (Non-Circular Cross Section) 30 Shaft Guide 33a Center Hole 33b Circular Hole 33c Expansion Hole 33c 'Expansion Hole (Open Groove) c Clearance

Claims (5)

[Claims] 1. A casing; a diaphragm dividing the casing; an actuating rod having a circular cross section connected to the diaphragm; and a shaft guide held by the casing for slidably guiding the actuating rod. The working rod has a non-circular cross section in a part thereof; and the shaft guide has a central hole having a shape corresponding to the non-circular cross section and the circular cross section of the working rod. A diaphragm-type actuator that is fitted to the operating rod in the axial direction of the operating rod. 2. The diaphragm type actuator according to claim 1, wherein the center hole of the shaft guide has a closed shape. 3. The diaphragm type actuator according to claim 1, wherein a central hole of the shaft guide is partially opened. 4. The diaphragm actuator according to claim 1, wherein the actuation rod is connected to a wastegate valve of a turbocharger of a vehicle, and the diaphragm is acted upon by an inlet pressure of the turbine. 5. An actuating rod which moves in the axial direction, the actuating rod having a circular cross section as a whole and a non-circular cross section in a part thereof; and slidably guiding the actuating rod. A shaft guide held by the casing; wherein the shaft guide has a central hole having a shape corresponding to the non-circular cross-section and the circular cross-section of the operating rod, and the axial guide extends from the axial direction of the operating rod to the operating rod. A non-split type to be fitted; a guide device for an operating rod.