US20040250678A1

US20040250678A1 - Pneumatic actuator with electrical position detector

Info

Publication number: US20040250678A1
Application number: US10/862,450
Authority: US
Inventors: Walter Bonotto; Marcello Pennicchi
Original assignee: Faist Componenti SpA
Current assignee: Faist Componenti SpA
Priority date: 2003-06-12
Filing date: 2004-06-08
Publication date: 2004-12-16
Also published as: FR2856110A3; ITAR20030013U1; DE202004009313U1; FR2856110B3; GB2402711A; GB0411906D0

Abstract

The invention consists of the combination of a pneumatic actuator part (1) and an electrical position detector part (2), the containing structures thereof sealingly combine along a contour edge (3), with the containing structure (8) of the electrical position detector part (2) contributing to implement the depression chamber (4) of the pneumatic actuator part (1) and inside thereof there is provided a small chamber (15) housing the resistive member (16), the thrust spring (19) and the head (17) of the sliding member bearing the electrical contacts (18) rubbing onto the resistance (16).

Description

BACKGROUND OF THE INVENTION

The invention relates to a pneumatic actuator with electrical position detector, apt for vehicles with internal combustion engines and in particular for adjusting and controlling the turbocompressors.

Pneumatic actuator devices combined with electrical position detectors of resistive type, utilized in the turbocompressors, are known.

In such devices the pneumatic actuator group, usually working under depression, has the structure defining the depression chamber on one side equipped with a guide for sliding the extracting member, on the opposite side it is provided with a hole, with sealing gaskets, therethrough the head of said extracting member connects to the sliding stem of the resistive sensor of the electrical position detector. The end of said sliding stem, in order to keep adhering to the head of the extracting member of the pneumatic actuator, is constantly pushed by a spring. The head of the sliding stem of the resistive sensor and said spring are housed inside the casing of the electrical position detector which is applied above the pneumatic actuator. Said head is equipped with sliding guides and with flexible and elastic electric contacts which are destined to rub onto a resistive film glued inside said casing of the electrical position detector so that the sliding of said head with electric contacts determines the change in value of the resistance part comprised between the output electrodes. The measurement of the resistance comprised between the output electrodes allows then to detect the position of the rubbing contacts and therefore the position of the extracting member of the pneumatic actuator.

Such device, then, results to be constituted by the combination of two distinct mechanisms: a pneumatic one and an electrical one. Such combination involves the mechanical assembly of two structures which requires a complex and therefore expensive intervention in changing and adapting the first structure, the pneumatic one. The two mechanisms are connected between them through the structure delimiting the chamber of the pneumatic actuator working under depression or however under a pressure different from the environmental one. Therefore, it is necessary utilizing appropriate gaskets which cannot guarantee the perfect sealing and thus the correct operation of the first mechanism, that is the pneumatic actuator.

On the contrary, the position detector has the resistive film on the inside thereof, which can wear quickly at high temperatures wherein the combined system is made to operate, when it is utilized in the turbocompressors, therefore its long duration cannot be guaranteed.

SUMMARY OF THE INVENTION

An object of the present invention is to implement a pneumatic actuator device with electrical position detector which results to have a moderate cost and assured operation, even in presence of high pressures or depressions.

Another object is to implement a device which cannot be opened, then which is not subjected to tamperings and/or alterations outside the firm manufacturing it.

Still another object is to implement a device with the incorporated electrical part apt to withstand even the high temperatures, therefore which is able to guarantee a long duration.

At last, another object is to implement a device enabling to be manufactured with smaller sizes than the ones of the corresponding known devices.

The invention which has allowed achieving such results concretizes in the combination of a pneumatic actuator part and an electrical position detector part, the containing structures thereof sealingly combine along the contour edge thereof. The containing structure of the electrical position detector part implements the upper part or “vault” of the depression chamber of the pneumatic actuator part and, inside thereof, it is equipped with a small chamber, closed by a plug on the lower side. Such chamber houses the resistive member, the thrust spring and the sliding member, the head thereof bears the contacts rubbing onto the resistance and the stem thereof, once crossed the plug, reaches the head of the extracting member of the pneumatic actuator part in order to move therewith.

Such device results particularly advantageous because its structure is relatively simple, it is very strong and therefore resistant and it has a moderate cost. It is advantageous because it cannot be opened and, however, each intervention inside thereof leaves traces in the junction sealingly joining the two parts, therefore it can be checked.

It is advantageous because the adjusting resistive member is a mechanical structure apt to withstand even the high temperatures, therefore it guarantees a long duration even when the invention is utilized in the turbocompressors of the vehicles with internal combustion engines.

Furthermore, it is advantageous because the whole structure thereof is compact and not much bulky.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages will be easily understood, particularly by the skilled persons working in the art, by reading the following detailed description related to the preferred embodiment solution, illustrated by way of example in the drawings of the enclosed figure wherein: [0014]
FIG. 1 is the prospective view of the invention; [0015]
FIG. 2 is the front view of the invention, sectioned with an axial plane; [0016]
FIG. 3 is the exploded front view of the electrical position detector part.[0017]
It is meant that the drawings are just exemplary in order to make easier the comprehension of the invention, without being a limitation therefor. [0018]

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Substantially, therefore, the invention consists of a device wherein two parts combine, one onto the other. The lower one is the [0019] pneumatic actuator part 1, the upper one is the electrical position detector 2. The two parts are implemented so that the containing structure 9 of the pneumatic actuator 1 and the containing structure 8 of the electrical position detector part 2 combine between them with a joint 3, sealing along the contour edge. In such implementation the containing structure 8 of the electrical position detector part 2 implements the upper part or “vault” of the depression chamber 4 of the pneumatic actuator 1. In the solution exemplified in the FIG. 2, the containing structure 9 of the pneumatic actuator part 1 on the top has an edge directed towards the outside. The edge of the flexible sheath 5, inside the central part thereof the cup-like structure 6 is housed, on the base thereof the extracting member 7 of the pneumatic actuator part 1 is fastened, rests on such edge.
The containing [0020] structure 8 of the electrical position detector part 2 is shaped like a cup upside-down with respect to the containing structure 9 of the pneumatic actuator part 1. The ending edge thereof is folded towards the outside in order to rest on the edge of the flexible sheath 5, therefore on the most inner part of the edge of the containing structure 9 of the pneumatic actuator part 1. The edge of the containing structure 9 is then folded towards the inside to compress and clamp the overlapped edges of the containing structure 8 and of the flexible sheath 5, until implementing the sealing joint 3. The containing structure 8 of the electrical position detector part 2 and the flexible sheath 5 originate the depression chamber 4 of the pneumatic actuator 1. Said chamber 4 communicates with the outside through the spout 10, placed on the containing structure 8 of the electrical position detector part 2. The containing structure 8 on the inside thereof also has the surface 11, shaped like a circular crown, thereagainst the spring 12 bucks. It opposes the sliding of the base of the cup-like structure 6 inside the containing structure 9 of the pneumatic actuator part 1 when, through the spout 10, a depression is produced inside the chamber 4.
The containing [0021] structure 8 of the electrical position detector part 2 on the inside thereof has a small chamber 15 inside thereof the variable resistance 16, the head 17 with the contacts 18 rubbing onto the resistance 16 and the spring 19 opposing the sliding of said head 17 are housed.
Said [0022] small chamber 15 is vantageously closed on the lower side by a plug 31 which is provided at least with a hole for the not-guided sliding of the shaft 26 of the head 17 which is equipped with rubbing electrical contacts 18. Said plug 31 can be provided with feet 32 for the positioning and snap-locking thereof into the seat destined to receive it or it can be fastened to said seat by welding, glueing and any other way.
The variable [0023] electrical resistance 16 is equipped with its own mechanical structure and/or with a support with feet buried in the jet, that is it can be stabilized in the position destined thereto by co-molding with the casing 8 of the electrical position detector part 2. However, it has the surfaces at sight therethrough the electrical connection with the rubbing contacts 18, integral to the head 17, is performed.
At last, inside said [0024] chamber 15 advantageously there are longitudinal grooves 21 for the positioning and the not-guided sliding at least of the head 17 equipped with contacts 18. All this to guarantee the electrical contact of the contacts 18 themselves onto the resistance 16 upon changing the position thereof inside the small chamber 15.
On the contrary, the [0025] spring 19 is sized to perform the thrust onto the head 17. The thrust is sufficient to keep inside the chamber 4 the end of the shaft 26 in contact with the head of the extracting member 7 of the pneumatic actuator part 1.
Upon the implementation, the manufacturing particulars could also be subject to variations, without altering the functional logique of the invention, therefore with said variations being comprised within the scope of the invention as defined by the following claims. [0026]

Claims

1. A pneumatic actuator with electrical position detector to be used in the vehicles with inner combustion engines and in particular in adjusting and controlling the turbocompressor, comprising a pneumatic actuator part (1) and an electrical position detector part (2), characterized in that the containing structure (9) of the pneumatic actuator part (1) and the containing structure (8) of the electrical position detector part (2) sealingly combine between them along a contour edge (3) and in that the containing structure (8) of the electrical position detector part (2) implements the “vault” of the depression chamber (4) of the pneumatic actuator part (1).

2. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in that the containing structure (8) of the electrical position detector part (2) has on the inside thereof a small chamber (15) inside thereof the variable resistance (16), the head (17) with the contacts (18) rubbing onto the resistance (16) and the spring (19) positioned so as to oppose the sliding of said head (17) are housed.

3. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in that the small chamber (15) inside the containing structure (8) of the electrical position detector part (2) is closed on the lower part by a plug (31) equipped at least with a central hole for the sliding of the shaft (26) projecting from the head (17).

4. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in that the containing structure (8) of the electrical position detector part (2) has the spout (10) therethrough it puts into communication the outside with the depression chamber (4) of the pneumatic actuator part (1).

5. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in having a variable electrical resistance (16) with structure with feet buried into the moulded jet therewith the casing (8) of the electrical position detector part (2) is implemented and with the surfaces at sight therethrough the electrical connection with the rubbing contacts (18) is implemented.

6. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in that in the small chamber (15), inside the containing structure (8) of the electrical position detector part (2), longitudinal grooves (21) are placed for the positioning and the not-guided sliding at least of the head (17) with the rubbing contacts (18).

7. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in having a spring (19) sized so as to perform the thrust onto the head (17) sufficient to keep inside the chamber (4) the end of the shaft (26) in contact with the head of the extracting member (7).

8. The pneumatic actuator with electrical position detector, as claimed in claim 1, characterized in that the containing structure (8) of the electrical position detector part (2) on the inside thereof has a surface shaped like a circular crown (11) thereagainst the spring (2) opposing the sliding of the cup-like structure (6) towards the containing structure (8) bucks when a depression is produced in the chamber (4).