This is a National phase application in the United States of International patent application PCT/EP2012/074143 filed Nov. 30, 2012 which claims priority on European patent application No. 11195125.7 filed Dec. 22, 2011. The entire disclosure of the above patent applications are hereby incorporated by reference.
The invention concerns a method of improving the pivoting of a wheel set or of an equipped wheel set for a scientific instrument or timekeeper, including at least one arbor arranged to pivot or oscillate about an axis of oscillation aligned on a wheel set axis formed by the axis of said arbor.
The invention further concerns a wheel set for a scientific instrument or timekeeper, including at least one arbor arranged to pivot or oscillate about an axis of oscillation aligned on a wheel set axis formed by the axis of said arbor, and including at least one flange connected to said wheel set arbor and projecting radially in relation to said arbor, said flange being substantially perpendicular to said wheel set axis.
The invention further concerns an equipped wheel set for a scientific instrument or timekeeper including a wheel set of this type.
The invention further concerns a mechanism for a scientific instrument or timekeeper including an equipped wheel set of this type and/or a wheel set of this type.
The invention also concerns a scientific instrument including this type of mechanism and/or an equipped wheel set of this type and/or a wheel set of this type.
The invention concerns the field of precision mechanics, notably mechanical scientific instruments, and in particular the fields of counters and precision instruments including mechanisms for measuring, displaying or comparing a flow rate, a consumption, or a time, including components which pivot or oscillate about an axis.
In the field of precision mechanical instruments, the quality of the guide members of certain components, which pivot or oscillate about an axis, is of great importance for the reproducibility over time of measurements made or signals generated. Any defects in the guide members, between, on the one hand, the pivots of a mechanism, and on the other hand, shoulders comprised in an arbor of the component, result in mediocre precision, and also wear and impaired performance over time. The geometric quality of machining operations is a necessary condition for precision operation, but this condition is often insufficient. Indeed, vibration behaviour, in particular in the presence of unbalances, directly affects the pressure applied to the bearings, and therefore lubrication requirements and maintenance requirements, in particular when the bearings and/or pivots are replaced or re-machined to re-establish the quality of the guide members after wear.
A static balancing of the components, returning their centre of mass to the axis of pivoting or oscillation, improves the situation and makes it possible to delay wear. However, the effects caused by inertial defects lead to considerable disruptions in the operation of the mechanism, and the service life over time.
The invention proposes to provide a solution to ensure a reduction in friction in the guide members of the rotating components of these precision mechanisms, and to improve the operating precision of such mechanisms. It also intends to allow an increase in the speeds of rotation and/or the oscillation frequencies of the components concerned.
Seeking greater precision means seeking improved adjustment of the wheel set, in particular by means of a high quality dynamic balancing operation.
The invention therefore proposes to dynamically balance the wheel set, i.e. return it to its principle axis of inertia on the axis of rotation.
To this end, the invention concerns a method of improving the pivoting of a wheel set or of an equipped wheel set for a scientific instrument or timekeeper, including at least one arbor arranged to pivot or oscillate about an axis of oscillation aligned on a wheel set axis formed by the axis of said arbor, characterized in that:
According to another characteristic of the invention, said adjustment is made by the asymmetrical addition and/or displacement and/or removal of material in relation to a plane defined by the two other principal axes of inertia of said wheel set or equipped wheel set.
The invention further concerns a wheel set for a scientific instrument or timekeeper, including at least one arbor arranged to pivot or oscillate about an axis of oscillation aligned on a wheel set axis formed by the axis of said arbor, and including at least one flange connected to said wheel set arbor and projecting radially in relation to said arbor, said flange being substantially perpendicular to said wheel set axis, characterized in that it is manufactured to include a first principal longitudinal axis of inertia close to that of said wheel set axis or coincident therewith, and two further principal axes of inertia defining together a median plane, and in that said flange includes a plurality of housings each receiving a movable mass which is position adjustable in said housing concerned, either only in a direction parallel to said wheel set axis, or only in a plane perpendicular to a radial line originating from said wheel set axis.
According to a characteristic of the invention, said median plane is within the thickness of said flange.
The invention further concerns an equipped wheel set for a scientific instrument or timekeeper including a wheel set of this type, characterized in that it also includes a drive means, and/or an elastic means of return or repulsion, and/or a magnetic means of return or repulsion, and/or an electrostatic means of return or repulsion.
The invention further concerns a mechanism for a scientific instrument or timekeeper including an equipped wheel set of this type and/or a wheel set of this type.
The invention also concerns a scientific instrument including this type of mechanism and/or an equipped wheel set of this type and/or a wheel set of this type.
Other features and advantages of the invention will appear upon reading the following detailed description, with reference to the annexed drawings, in which:
FIG. 13 similarly shows a fluted mass and
The invention concerns the field of mechanical scientific instruments, and in particular the fields of counters and precision instruments including mechanisms for measuring or comparing time, including movable components which can pivot or oscillate about an axis.
More specifically the invention is concerned with the optimum balancing of a wheel set 1 or an equipped wheel set 40.
In the following description, “wheel set” means any arbored component that can pivot or oscillate about a wheel set axis D, corresponding to the axis of the arbored part. This wheel set may, where appropriate, but not necessarily, include toothings, pinions, other drive means such as grooves or shoulders, and elements for attachment or cooperation with a drive means, and/or an elastic means of return or repulsion, and/or a magnetic means of return or repulsion, and/or an electrostatic means of return or repulsion, or suchlike. Here “equipped wheel set” 40 means a mechanical sub-assembly or assembly including at least one wheel set 1 of this type and all or part of a drive means, and/or an elastic means of return or repulsion, and/or a magnetic means of return or repulsion, and/or an electrostatic means of return or repulsion.
“Flange” means a part projecting substantially radially, preferably of revolution about the wheel set axis, and whose diameter is larger than that of the arbor. The same wheel set may naturally include several flanges of this type, of which some may have specific functions, such as toothed wheels, pulleys, or suchlike.
The invention proposes to dynamically balance wheel set 1, or equipped wheel set 40, i.e. return it to its principal axis of inertia on the axis of rotation. The different non-limiting embodiments and the Figures illustrate the application of the invention to a bare wheel set 1 and are, of course, applicable to an equipped wheel set 40.
Other than seeking perfect balancing, it is also possible to create controlled unbalance, i.e. to incline the principal axis of inertia of the wheel set at a certain angle in a certain direction in relation to:
For this two steps are necessary:
To this end, the invention concerns a method for improving the pivoting of a wheel set 1 or an equipped wheel set 40 for a scientific instrument or timekeeper. This wheel set 1 includes at least one arbor 10 arranged to pivot or oscillate about an axis of oscillation aligned on the wheel set axis D formed by the axis of arbor 10, and preferably at least one flange 2 whose footprint diameter is greater than that of arbor 10. In the case of a wheel set reduced simply to arbor 10, it remains possible to perform dynamic balancing by using certain implementation variants of the invention, applicable to an arbor of this type. Only the variants set out below, which require components supported on both sides of a thin flange, and which are difficult to implement on a substantially cylindrical arbored part, will be more restricted to wheel sets including a flange that is substantially flat and substantially perpendicular to the wheel set axis.
This wheel set 1 or equipped wheel set 40 is arranged to oscillate about an oscillation axis aligned on wheel set axis D.
According to the invention:
In a specific implementation, the predetermined tolerance range includes an upper limit corresponding to the desired value. In other applications, the tolerance range is around this desired value.
Preferably, said desired value of the resulting unbalance moment is determined in the form of a maximum admissible value of the resulting unbalance moment of the wheel set or equipped wheel set about the wheel set axis. This maximum value corresponds to a predetermined maximum angular divergence between the first principal longitudinal axis of inertia of the wheel set or equipped wheel set on the one hand, and the wheel set axis on the other. The adjustment of the value of the dynamic balance moment of the wheel set or equipped wheel set therefore has the effect of bringing the first principal longitudinal axis of inertia closer to the wheel set axis, below the predetermined maximum angular divergence.
In a specific implementation of the invention, this adjustment is made by the asymmetrical addition and/or displacement and/or removal of material in relation to a plane defined by the two other principal axes of inertia of the wheel set or equipped wheel set.
In a specific embodiment, an addition and/or displacement and/or removal of material is carried out on at least one flange comprised in the wheel set, projecting radially in relation to its arbor.
In a specific embodiment, an addition and/or displacement and/or removal of material is carried out on the wheel set arbor.
In a specific embodiment, an addition and/or displacement and/or removal of material is carried out on least one arm comprised in said wheel set between said arbor and another off-centre part of said wheel set.
In a specific implementation of the invention, the static balancing is performed prior to the adjustment of the value of the dynamic balance moment.
In a further specific implementation of the invention, the static balancing is performed simultaneously with the adjustment of the value of the dynamic balance moment.
In a specific implementation of the invention, this maximal admissible value of the resulting unbalance moment of the wheel set or equipped wheel set about the wheel set axis is set at zero, so as to make the first principal longitudinal axis of inertia of the wheel set or equipped wheel set coincident with the axis of the wheel set.
In a specific implementation of the invention for an oscillating wheel set, this predetermined speed of rotation is set at the maximum angular speed calculated for the wheel set or equipped wheel set, considered during its oscillation in use.
In a specific implementation of the invention, prior to the static balancing and dynamic balancing, on flange 2 when the wheel set includes one, cylindrical or fluted housings, arranged to receive movable cylindrical or fluted masses, are machined in an axial direction parallel to the wheel set axis. All or part of the adjustment is then carried out by moving these movable masses inserted into some of these housings, in relation to the plane defined by the two other principal axes of inertia of the wheel set or equipped wheel set. If no flange is present, the housings are machined in wheel set arbor 10.
In a specific implementation of the invention, prior to the static balancing and dynamic balancing, these movable masses are confined in and made inseparable from the flange, either by creating a wheel set or equipped wheel set in a single piece with these movable masses, or by extending at least one end of each movable mass to prevent the extended area from passing through the corresponding housing for said movable mass.
According to a specific implementation of the invention, all or part of this adjustment is carried out by deforming a flange 2 comprised in the wheel set or equipped wheel set, in an asymmetrical manner in relation to the plane defined by the two other principal axes of inertia of the wheel set or equipped wheel set.
In a specific implementation of the invention, prior to the static balancing and dynamic balancing, a flange 2, comprised in the wheel set or equipped wheel set, is machined with internally threaded radial housings arranged to receive asymmetrical headed screws movable in a radial direction in relation to the wheel set axis, and all or part of said adjustment is carried out by moving these screws screwed into some of the internally threaded housings. If no flange is present, internally threaded housings of this type are machined in the wheel set arbor 10.
In a specific implementation of the invention, when the resulting unbalance moment of the wheel set or equipped wheel set is measured in relation to the wheel set axis, the unbalance is noted in an angular position in relation to an angular guide-mark on the wheel set or equipped wheel set, such as a pin, a notch, a piercing, an additional component, a mark, or suchlike.
In a specific implementation of the invention, prior to the static balancing and dynamic balancing, a flange, which is comprised in the wheel set or equipped wheel set, is machined to be out of truth in the flat by a predetermined value. In particular, in a specific embodiment, an unbalance and/or resulting unbalance moment are intentionally created in a specific angular direction, and in an offset manner in relation to the median plane P.
In order to correct the unbalance, the following non-limiting methods can advantageously be used, combinable with each other, and applicable on a flange 2 or a wheel set arbor 10, or even a connecting arm between the arbor and a peripheral mass, or on a peripheral mass of this type.
The Figures show, in a non-limiting manner, adjustments carried out on a wheel set flange, as it is easier to make an inertia correction in proximity to the largest diameter of the wheel set, which means that only minimal mass corrections are required. In order to simplify the diagram, only the flange is shown; the wheel set arbor is not fully shown. Naturally, the described arrangements are also applicable to other forms of wheel sets, and the adjustable machined portions or components may be positioned on other parts of the wheel set, according to their accessibility.
With more specific reference to the removal of material,
Advantageously, when, preferably, the theoretical principal axis of inertia is formed by wheel set axis D, and the median plane P is calculated to include the two secondary axes of inertia, the machined elements are created on both sides of plane P. The Figures show, in a non-limiting manner, different possibilities: on both sides of the median plane (
Naturally, the possibilities for distribution are similar with regard to the addition or displacement of material.
An additional component is advantageously movably mounted on the wheel set structure. To this end, wheel set 1 includes a slidably movable part that is driven on, or clipped or mounted with play, either in rotation or axially. Providing at least one guide surface using notches or suchlike makes it possible for the additional component to assume discrete positions.
The mobility of the additional component may also be achieved by screwing/unscrewing.
An adjustment component can thus be mounted with play, and tightened by a screw, by sliding for example. Thus,
The adjustment component may also be clipped on an arm 3 or on flange 2 of wheel set 1. For example, it may consist of a flexible object clipped on a rigid part, for example an inertia-block on an arbor, or even of a rigid object clipped on a flexible part, for example an arbor in a slot.
An adjustable component may also be an additional component simply bonded, welded or even riveted to the structure of the wheel set.
In a variant of the embodiment, a flexible additional object is made to bend.
A second variant of this adjustment by bending employs a displacement of the fixing of the flexible part, which may be provided with notches, and with the flexible part supported against a cam or a fixed area.
Thus,
In order to avoid creating an unbalance, it is possible to use additional components with a fixed position in projection in median plane P, and movable in an axial direction A parallel to axis D of wheel set 1. This is particularly the case for the embodiments in
In a specific arrangement, the adjustment components are arranged symmetrically in pairs in relation to axis D of wheel set 1. Thus, the symmetrical adjustment of the components in a pair of this type does not impair the static balancing of the wheel set.
If necessary, each adjustment component can be moved independently of the others.
In the first case, the centre of inertia of the adjustment component is situated on the axis of rotation of this component, and/or this component is in translation along an axis. If the centre of inertia is moved along the axis, for example during screwing-in, and if the projection in median plane P of the centre of inertia of the component also moves, the object opposite must be moved in a symmetrical manner. Otherwise, each adjustment component can be moved independently.
In a second case, the centre of inertia of the adjustment component is situated outside the axis of rotation of the component. It is therefore necessary to perform a symmetrical rotation of the opposite component in the pair.
This is the case in
The invention also concerns a wheel set 1 for a scientific instrument or time keeper, including at least one flange 2 connected, either directly or by means of an arm, to a wheel set arbor 10 aligned on a wheel set axis D. This flange 2 is preferably substantially perpendicular to wheel set axis D. Wheel set 1 is arranged to oscillate about an oscillation axis aligned on wheel set axis D.
According to the invention, this wheel set 1 is manufactured to include a principal longitudinal axis of inertia close to wheel set axis D or coincident therewith, and two other principal axes of inertia defining together a median plane P. In a specific embodiment, this median plane P is within the thickness of flange 2.
Flange 2 includes a plurality of housings each receiving a movable mass, which is position adjustable in the housing concerned, either only in a direction A parallel to the wheel set axis, or only in a plane perpendicular to a radial line R originating from wheel set axis D.
In a specific implementation of the invention, each housing of this type and/or each corresponding movable mass includes arresting means to allow the movable mass to be held in several distinct positions where its centre of gravity is remote from median plane P.
In a specific implementation of the invention, each housing of this type and/or each movable mass includes elastic return means for holding the movable mass in position in the housing.
The invention further concerns an equipped wheel set 40 for a scientific instrument or timekeeper including a wheel set 1 of this type, and also including at least one drive means, and/or an elastic means of return or repulsion, and/or a magnetic means of return or repulsion, and/or an electrostatic means of return or repulsion, attached to this at least one wheel set.
The invention further concerns a mechanism 50 for a scientific instrument or timekeeper including an equipped wheel set 40 of this type and/or a wheel set 1 of this type.
The invention also concerns a scientific instrument 60 including a mechanism 50 of this type and/or an equipped wheel set 40 of this type and/or a wheel set 1 of this type.
In a specific implementation, this scientific instrument 60 is a watch, which includes a movement 50 and the wheel set 1 is a balance, whose flange 2 is formed by a disc or a felloe, the equipped wheel set 40 is a sprung balance.
The invention allows for a substantial reduction in the stress on the pivots, facilitates lubrication, and increases the service life of the mechanisms, and in particular the useful service life, i.e. the period in which the mechanism provides a reproducible response to an identical solicitation from an energy source, or from a signal, or from another mechanism or sensor, or suchlike. The invention makes it possible to improve the stability of operation of a wheel set dynamically balanced in this manner.
Number | Date | Country | Kind |
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2023/11 | Dec 2011 | CH | national |
11195125 | Dec 2011 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2012/074143 | 11/30/2012 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2013/092172 | 6/27/2013 | WO | A |
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Entry |
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Dictionary Definition of “out of truth in the flat” from Illustrated Professional Dictionary of Horology, retreived Jul. 22, 2015. |
International Search Report Issued Feb. 26, 2013 in PCT/EP12/074143 Filed Nov. 30, 2012. |
Number | Date | Country | |
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20150198927 A1 | Jul 2015 | US |