GB2277368A

GB2277368A - Throttle butterfly valve

Info

Publication number: GB2277368A
Application number: GB9403175A
Authority: GB
Inventors: Hans Gerards
Original assignee: Pierburg GmbH
Current assignee: Pierburg GmbH
Priority date: 1993-04-24
Filing date: 1994-02-18
Publication date: 1994-10-26
Also published as: GB9403175D0; FR2704279A1; DE4313454A1; FR2704279B1; IT1266465B1; ITRM930844A0; ITRM930844A1

Description

2277368 1 ARRANGEMENT OF A THROTTLE BUTTERFLY The invention relates to an

arrangement of a throttle butterfly in an exhaust duct of an internal combustion engine! comprising a housing with a throttle-butterfly shaft, the throttle-butterfly shaft being mounted in bearing sleeves which are loaded under spring force against axial walls of the housing.

From DE-Al 38 02 243 a proposal is known for mounting a throttlebutterfly shaft by means of spherical cap-shaped bearing sleeves which are supported under spring force against conical housing walls. By this means, alignment errors of the bearing bores on both sides of the exhaust duct can be compensated for. However, it has been shown in practice that conventional springs age or break prematurely under the heat of the very hot exhaust gases in the vicinity of the exhaust valve and, as a result, lose clamping forces, resulting in the arrangement exhibiting leaks or malfunctions.

Proceeding from this, the invention is therefore based on the object of finding means for a solution by which a lasting imperviousness of the throttle-butterfly arrangement is achieved, a reduction in installation space also being sought. This object is solved by the characterizing features specified in Claim 1. Advantageous further developments are specified by the subclaims.

Accordingly this invention provides an arrangement of a throttle butterfly in an exhaust duct of an internal combustion engine, comprising a housing with a throttle butterfly shaft, the throttle butterfly shaft being mounted in bearing sleeves which are loaded under spring force against axial walls of the housing, which is characterized in that the spring force is produced by an assembly of spring elements the individual elements being composed of a ceramic material, for example partially stabilized zirconium dioxide.

9 2 An exemplary embodiment of the invention is shown in the drawing and is described below.

Figure 1 shows a longitudinal section through a throttle housing; Figures 2, 3 and 4 show alternative embodiments of a spring element according to Figure 1; Figure 5 shows a view of a spring element as an individual part.

Figure 1 shows a throttle housing 1 with connection stubs 2, 3 and a rotatably mounted throttle-butterfly shaft 4 to which a throttle butterfly 5 is fastened.

The throttle-butterfly shaft 4 projects on both sides of an exhaust duct 6 outwards through a bearing bore 7. The left-hand side of the throttlebutterfly shaft 4 is connected to an operating lever 8.

The two sides of the throttle-butterfly shaft 4 are, as shown on the bisected half, mounted by means of bearing sleeves 9 which are loaded by a clamped assembly 10 of spring elements and bear against an axial wall 11 of the bearing bore 7. The bore 7 is closed in this case by a solid disc 12, the bore on the left-hand side by a perforated disc through which the throttle-butterfly shaft 4 projects. The force of the assembly 10 of spring elements is dimensioned such that an aligned position of the bearing sleeves 9 is not changed when the throttle-butterfly device is operating normally.

1 3 According to the invention, the spring elements 13 of the assembly 10 of spring elements are formed from a ceramic material, for example, in this case, from a partially stabilized zirconium dioxide.

The assembly of spring elements is composed of a series arrangement of identical spring elements 13 which, as shown in Figure 1, are composed of a V-profile ring 14 and arranged in a row directly adjacent to one another. Assuming that per profile ring 14 there is a permissible deformation of 0.2 millimetres, then in the case of 3 profile rings this deformation adds up to form a total deformation of 0.6 millimetres, with clamping force unchanged.

Figure 2 shows an alternative embodiment of the spring element as an Lprofile ring 15, this being flat and on the inside having a collar projection 16. The assembly 10 of spring elements is formed here by an arrangement in which the collar projections 16 bear against one another and there lie, between the L-profile rings 15, arranged in this manner in pairs, shims 17 having an outer diameter which is identical to that of the L-profile rings 15, the terminating profile rings 15 being supported against loose shims 17 or directly against collar projections of the bearing sleeves 9 or of the disc 12 or perforated disc. If the collar projection 16 were to be arranged on the outside of the L-profile ring 15, an arrangement would result in which the shims 17 then have an inner diameter which is identical to that of the L-profile rings 15.

1 4 Figure 3 shows an embodiment with flat spring washers 18 which are supported against inner and outer shims 19, 20, respectively.

As is shown in Figure 4, these inner and outer shims can be dispensed with if, instead, inner and outer collar projections 21, 22 are arranged directly on the spring washer 18, to be precise one collar projection 21 on one side and the other collar projection 22 on the other side, resulting in a double L-profile.

Figure 5 shows a spring washer according to Figure 3 or 4 as an individual part with recesses 23 for increasing the elasticity or reducing the clamping forces.

Of course these recesses can also terminate in the outer diameter of the spring ring, as a result of which spring arms are formed, without departing from the scope of the invention.

With the invention, an arrangement of the throttle butterfly has become possible which lies very tightly against the exhaust valves of the internal combustion engine, resulting in a series of advantages without the risk of destroying the spring elements.

Since these spring elements are very resistant to high temperatures by virtue of the material found, they are not subject to aging and therefore have a virtually unlimited service life.

Of course, the spring elements can also be arranged individually.

Claims

Arrangement of a throttle butterfly in an exhaust duct of an internal combustion engine, comprising a housing with a throttle-butterfly shaft, the throttle-butterfly shaft being mounted in bearing sleeves which are loaded under spring force against axial walls of the housing, characterized in that the spring force is produced by an assembly (10) of spring elements the individual elements being composed of a ceramic material, for example partially stabilized zirconium dioxide.
2. Arrangement according to Claim 1, characterized in that the spring elements are designed as flat spring washers (18).
3. Arrangement according to Claim 1, characterized in that the spring elements are designed as an L- or double L-profile ring (15).
4. Arrangement according to Claim 1, characterized in that the spring elements are designed as a V-profile ring (14).
5. Arrangement according to Claim 2, 3 or 4, characterized in that the spring elements have recesses (23).
6. Arrangement according to one of the preceding claims, characterized in that the spring elements (13, 14, 15, 18) are arranged individually or in a multiplicity as an assembly and are employed in conjunction with spacer discs (19).