compensation of rate changes in the table

Abstract

One aspect of the invention relates to a method for compensating the rate as a function of temperature of a watch (1) in which, in an internal volume V occupied by n moles of a gas with constant R, a waterproof case (2) contains a movement (3) with an oscillator (4), in which the pressure coefficient Cp and the humidity coefficient Ch of the movement (3) are determined, the optimal value Cto of the thermal coefficient Ct of the oscillator (4) is calculated so as to define its rate as a function of the relative linear variation of the temperature T in order to compensate for pressure and humidity deviations, and, for after-sales, the watch (1) is equipped with a compensation device (10) to change the pressure P and / or the constant R and / or the amount of gas and / or the temperature T in the case (2), or, in the factory, by modifying the thermal coefficient of the elastic return means of the oscillator (4) by modifying the oxide layer and / or applying or ablating a coating, and / or modifying the amount and / or the nature of the gas in the watch, and / or modifying the internal volume of the case (2).

Description

Technical Field

[0001] The present invention relates to a method for compensating for a rate that varies with temperature changes in a waterproof watch, wherein the waterproof case contains a movement, the movement itself including an oscillator, and the case, after being shipped with an initial rate set, contains an internal volume V, the internal volume V being occupied by n moles of a gas having a constant R that substantially conforms to the ideal gas law.

[0002] The present invention further relates to a table suitable for implementing the method, particularly during after-sales operations.

[0003] This invention relates to the field of rate regulation in mechanical or electromechanical meters. Background Technology

[0004] The speed of a watch is affected by many parameters, such as (non-limitingly) the watch's spatial position, lubrication, wear, the winding of the springs that form the energy source, friction, and the physical parameters of the environment in which the watch is placed.

[0005] Temperature-dependent rate variations are a constant concern for watch manufacturers. The elastic return mechanism of the oscillating movement is particularly sensitive to temperature changes. In specific, and non-limiting cases, where these elastic return mechanisms include a balance spring or several balance springs, the thermal coefficient Ct of each balance spring causes the movement rate to vary with temperature. As an example, and for the sake of simplicity, the rate can be considered to change substantially linearly with respect to the thermal coefficient Ct.

[0006] To achieve better movement accuracy, the target thermal coefficient is 0 seconds per Kelvin per day. With this parameter, temperature variations should not affect the movement's rate. For products with the same movement, the typical thermal coefficient distribution is a symmetrical curve, closer to a triangular peak than a bell shape.

[0007] In watchmaking, it is well known that the speed of a movement varies with the pressure of the medium in which it is situated. Several explanations can be offered, such as the change in the moment of inertia of the oscillator (the balance wheel and the load of air), because the density of the load air changes, and therefore its moment of inertia changes. The cases of the balance wheel and the air are specific; a more general reference would be the inertial mass and the gas or gas mixture. Various experiments have shown that if the pressure decreases, the speed increases.

[0008] Therefore, it is necessary to compensate for the meter's rate, which varies according to changes in the following physical parameters: the temperature of the medium; the user's body temperature; and the expansion or contraction of the meter casing based on temperature, location, pressure, altitude, and humidity. However, no simple development can specifically address the problems inherent in temperature and pressure changes. Summary of the Invention

[0009] This invention relates to compensation for rate changes in a meter based on temperature and pressure.

[0010] For this purpose, according to claim 1, the present invention relates to a method for compensating for the rate of change of a waterproof gauge with temperature variations.

[0011] The present invention also relates to a table suitable for implementing the method, particularly during after-sales operations. Attached Figure Description

[0012] The objects, advantages, and features of the present invention will become clearer from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0013] - Figure 1 Three graphs are superimposed, showing on the y-axis the rate (in seconds per day) of three different watch movements based on the pressure (in hectopascals) on the x-axis.

[0014] - Figure 2 For the same watch movement, two graphs are superimposed, showing the pressure (in hectopascals) on the y-axis based on time (in days) on the x-axis. One is a solid line calculated using the ideal gas law, and the other is the measured result.

[0015] - Figure 3 A table is schematically shown, in which a waterproof housing contains a movement, the movement itself including an oscillator equipped with a compensation device, which includes a waterproof volume measuring device for modifying the internal volume of the housing, a waterproof gas injection or extraction conduit, and a heating device for controlled and instantaneous increase of its internal temperature. Detailed Implementation

[0016] This invention relates to compensation for rate changes in a meter based on temperature and pressure.

[0017] Experiments conducted in a pressure vessel showed a relatively good linear relationship between the rate of change and pressure changes from atmospheric pressure (970 hPa) to pressures as high as 200 hPa. The rate of change on the y-axis, in seconds per day, depends on the pressure on the x-axis, in hectopascals. The measurements were taken in the pressure vessel. Figure 1 The measurements of various conventional mechanical movements, tested and verified, are shown. Under all other conditions being equal, a general linear process is followed according to the daily rate of pressure, with the slope of the top curve being (-0.0206), the slope of the middle curve being (-0.0161), and the slope of the bottom curve being (-0.0145).

[0018] Equipped with Figure 1 The experiment with a different measuring instrument showed a rate change on the order of 1.95 seconds per day at an altitude difference of approximately 570 meters. This was based on the following altitude formula:

[0019] - It can be observed that the rate of change of this gauge with altitude is on the order of approximately 0.03 seconds per hPa per day. This value is known as the pressure coefficient: Cp.

[0020] Regarding pressure changes based on temperature, we will assume the ideal gas law. This is sufficient to limit the situation.

[0021] In a closed table, the available air volume is considered to be given and finite (assuming zero leakage). We also assume that the pressure difference between the inside and outside of the table is insufficient to deform the table; the available volume in the table remains constant and therefore constant.

[0022] Experiments show that these approximations are relatively accurate. Figure 2 In this process, the measured pressure is compared with the theoretical pressure based on the ideal gas law. A comparison was made. It was observed that the measured results were quite comparable to the theoretical approximations. Furthermore, experiments showed that even with a large pressure difference between the inside of the watch and the medium it was in, leakage from the waterproof watch was relatively low. Therefore, we will assume the watch is completely waterproof.

[0023] The initial assumptions state that leakage from the meter is considered zero, the meter case cannot deform, and the enclosed gas remains constant. Therefore, it can be concluded that parameters n, R, and V are constants; thus, the pressure changes linearly with temperature.

[0024] This invention proposes a method to address compensation related to changes in temperature and pressure. The aim of combining these two effects is to make their effects cancel each other out (or minimize them). For the user, the main benefit is improved accuracy when wearing the watch.

[0025] The effects of humidity are less than those of temperature and pressure. In the operational assumptions, within the normal range of watch wear, humidity levels do not vary significantly with temperature or pressure. Approximate calculations include neglecting this variation.

[0026] To simplify the calculation, the following assumptions were made:

[0027] - The pressure in the table changes essentially linearly with temperature: ;

[0028] - The movement rate is based on the thermal coefficient Ct of the oscillator (especially the balance wheel of the hairspring), which varies essentially linearly: ;

[0029] - The movement speed is based on a substantially linear change in gas pressure: .

[0030] Therefore, the present invention relates to a method for compensating for rate variations caused by temperature changes in a waterproof watch 1, wherein a waterproof case 2 comprises a movement 3, which in turn includes an oscillator 4. The case 2, shipped after an initial rate setting, contains an internal volume V occupied by n moles of a gas having a constant R, substantially conforming to the ideal gas law. The constant R (or Avogadro's constant) is known. This depends on the gas present in the watch (in our case, generally air). The number of moles n will depend on the watch's closing conditions (e.g., atmospheric pressure, temperature, or closing and locking the watch back).

[0031] The available volume V depends on the geometry of the shell. This can be affected by optionally modifying the design of the external parts.

[0032] According to the present invention, the pressure coefficient Cp of the movement 3 is determined in the factory by measurement and / or calculation, thereby defining the rate of the movement 3 according to the relatively linear change of the pressure P of the gas (or applicable gas mixture). The pressure coefficient Cp of the movement can be obtained by experimental measurement or theoretical calculation. It depends on each movement.

[0033] Similarly, after measurement and / or calculation, the value of the humidity coefficient Ch of the movement 3 is determined at the factory, thereby limiting the rate of the movement 3 according to the maximum relative linear change in humidity H in the movement 3: m(H) = Ch * H. If there is no linear change, the maximum slope value of the highest tangent line of the rate / humidity curve is considered.

[0034] The optimal value Cto of the thermal coefficient Ct of the oscillator 4 is calculated, thereby limiting the rate of the oscillator 4 to a relatively linear change with respect to temperature T. This optimal value Cto aims to compensate for pressure and humidity deviations according to the following formula:

[0035] - .

[0036] Indeed, to improve the accuracy of the watch (rather than the accuracy of the movement), we can establish the following relationship: m(T) + m(P) + m(H) = 0, thus obtaining the value Cto above. In fact, Cto is the optimal value for which the sum of the rate deviations attributable to pressure, temperature, and humidity is zero; if this cannot be achieved, then Cto is a value for which the sum of these rate deviations has the minimum possible value.

[0037]

[0038] In this example, the thermal coefficient and pressure coefficient are assumed to be constants, and the rate is assumed to vary linearly with temperature. If these parameters obey nonlinear laws based on temperature, it would be possible to establish a similar model.

[0039] Considering that relative humidity will vary with temperature, and that the watch's rate will vary based on humidity changes (via Ch), this theoretical model incorporates a humidity parameter. However, in temperate regions, this parameter is negligible because humidity has a much smaller effect on the rate than temperature. In simplified calculations, the humidity coefficient Ch of movement 3 is determined to be 0. To improve the watch's accuracy (rather than the movement's accuracy), a simplified relationship can be established: m(T) + m(P) = 0, thus, based on the ideal gas law, and using the formula... Calculate the optimal value Cto of the thermal coefficient Ct of the oscillator 4.

[0040] The method can be implemented differently depending on whether it includes performing the initial factory setup or after-sales operation. In the after-sales case, it is difficult or even impossible to have a controlled atmosphere chamber, but it is necessary for after-sales technicians to perform the setup using special tools that are not available to the end user. In the factory setup case, the scope is broader because devices for creating a controlled atmosphere and controlled temperature can be combined, and these devices can also be specifically designed for after-sales service.

[0041] Therefore, according to the present invention:

[0042] - Whether for aftermarket applications or when embossed at the factory, Table 1 is equipped with a compensation device 10, which is arranged within the housing 2 to change the pressure P and / or the properties and constant R of the gas and / or the amount of gas and its molar number n and / or temperature T.

[0043] - Or, for preparation in the factory, modify the thermal coefficient of the elastic return device included in the oscillator 4 by modifying the oxide layer thickness and / or applying a coating and / or by local ablation, and / or modify the molar number of gases in the table and / or the properties of gases in the table, and / or modify the internal volume of the shell 2.

[0044] More specifically, the pressure P and / or the number of moles n are modified by changing the pressure P and / or the temperature T in Table 1 before closing shell 2.

[0045] equation This indicates that, based on the environment within shell 2 in Table 1 (current gas with a constant R, internal volume V, and molar quantity n in the table), the thermal coefficient Ct of the oscillator 4 is related to the pressure coefficient Cp. To make the table insensitive to temperature (or reduce its sensitivity), the following parameters can be treated independently or in combination:

[0046] - Thermal coefficient Ct of oscillator 4;

[0047] - A constant R related to the properties of the current gas or gas mixture;

[0048] - The available volume V in shell 2 of Table 1;

[0049] - Current gas quantity n.

[0050] The first embodiment includes processing the thermal coefficient of the oscillator 4. In the specific, non-limiting case where the oscillator 4 is a balance spring, when producing a silicon and / or silicon oxide balance spring, the thermal coefficient Ct of the regulating mechanism assembly can be specifically adjusted according to the thickness of the oxide layer covering the balance spring.

[0051] Let's consider that the rate of change in the movement depends on the pressure as follows: Cp = 0.015 seconds per day per 100 Pascals. For external watch parts with a universal case, we experimentally obtain a constant (n*R) / V of approximately 3.3 hPa / K. This is calculated based on measurements of pressure and temperature within the watch head according to the ideal gas law.

[0052] To minimize the watch's sensitivity to temperature changes, it is necessary to set the oscillator's thermal coefficient to 0.05 seconds per Kelvin per day. This value is based on the equation... Perform the calculation.

[0053] By setting the thermal coefficient of the balance wheel to a value different from 0 Kelvin per day, the timing measurements in the movement are disturbed. For example, when running a timepiece with phases of 8°C and 38°C, a rate difference on the order of 1.5 seconds per day occurs due to the thermal coefficient of the movement between the hot and cold phases. However, if the movement is encapsulated in the table of the previous example (Cp=-0.015, (n*R) / V=3.3), the rate is practically insensitive to temperature changes.

[0054] More specifically, the elastic return device of the oscillator 4 is made of silicon and / or silicon oxide, and the thermal coefficient of these elastic return devices is modified during the fabrication process in the factory by changing the thickness of the silicon oxide layer.

[0055] More specifically, the elastic return device of the oscillator 4 is made in the form of a thin elastic strip using the “LIGA” method, and during the manufacturing process in the factory, the thermal coefficients of these elastic return devices included in the oscillator 4 are modified by applying and / or localized ablation.

[0056] More specifically, the elastic return device of the oscillator 4 is made in the form of a thin elastic strip by stretching or rolling, and during the manufacturing process in the factory, the thermal coefficient of these elastic return devices included in the oscillator 4 is modified by applying and / or local ablation.

[0057] The second embodiment involves modifying the gas quantities in the table. In fact, by changing the number of moles of gas in the table, Ct and Cp can be compensated. The relationship between these two constants is expressed by the equation... For example, if Ct = 0.055 seconds / day / Kelvin, Cp = -0.015 seconds / day / hexapascal, and (n*R) / V = 3.3 hexapascal / Kelvin, then the number of air molecules in the table should be multiplied by 1.1 (0.055 / (0.015*3.3) = 1.1).

[0058] To change the number of molecules in the table, there are two solutions:

[0059] - Close the meter in an environment with a limited pressure: if the atmospheric pressure is 970 hPa, then it should be 1067 hPa (970 * 1.1) when sealed, so that the meter's rate is not sensitive to temperature;

[0060] - Alternatively, close the meter at the given meter temperature: if the ambient temperature is 23°C (~296K), the meter should be heated to approximately 53°C (~329K=296*1.1).

[0061] Temperature and pressure are linked by the ideal gas law; therefore, it is necessary to ensure that these two parameters are monitored in order to prevent errors related to changes in atmospheric pressure, altitude, or temperature.

[0062] Modifying the pressure before encapsulation is relatively complex, especially in after-sales service when the store lacks suitable equipment. Modifying the temperature of the meter before encapsulation seems relatively easy to achieve; for example, by placing the open meter on a heating or cooling plate. The main problem with this approach is that Ct and Cp only cancel each other out when their signs are opposite. Furthermore, a 5% change in Ct represents approximately 20°C. Therefore, it can be expected that the temperature required to compensate for Ct may be difficult to achieve.

[0063] More specifically, during the preparation process in the factory, the number of gas moles in Table 1 is modified by closing shell 2 at a calculated pressure so that the rate of the meter is insensitive to temperature, or by closing shell 2 at a calculated temperature so that the rate of the meter is insensitive to temperature, and then slowly cooling shell 2 after it is closed.

[0064] The third embodiment involves modifying the composition of the gases in the table. By modifying the composition of the gases in Table 1, for example by closing Table 1 in a saturated medium containing another gas, the equations... The constant R in the equation will therefore be modified. For example, if Ct = 0.02 sec / day / Kelvin, Cp = -0.015 sec / day / HbA1c, and the constant (n*R) / V = 3.3 HbA1c / Kelvin, the air in the meter (R = 287 J / kg / K) can be replaced with sulfur dioxide (R = 130 J / kg / K). In this case, the correction will be 90% (0.015 * 3.3 * 130 / 287 = 0.0224). As a general rule, the influence of the meter's internal temperature can theoretically be minimized by selecting the correct gas or gas mixture (modifying R without affecting the contact material). It is assumed that the effect of modifying the gas on Cp is negligible. Furthermore, considering the variability of Ct, this means that a specific gas mixture is required for each meter. Another drawback is that each meter closure should be performed in a controlled atmosphere. Finally, this solution is theoretically only feasible when the signs of Ct and Cp are opposite.

[0065] More specifically, during preparation in the plant, the properties of the gas contained in the table are modified by exchanging the gas completely or partially with a new gas or gas mixture having another value of the constant R, which is suitable for appropriate adjustment of the thermal coefficient Ct, so that the rate of the table is insensitive to temperature.

[0066] More specifically, shell 2 is sealed after gas exchange to prevent any action by the user without special tools.

[0067] The fourth embodiment includes processing the geometry inside the table. In fact, the equations... It is possible to Let's consider Cp = -0.015 seconds / day / hexapach and Ct = 0.04 seconds / day / Kelvin. For a given practical situation, we have determined (n*R) / V = 3.3 hPa / K. To minimize the impact on the watch's rate, the air volume in the watch should be corrected to be 1.24 times (3.3*0.015 / 0.04) times larger than the currently available air volume. Since the Ct value varies with different movements, this means that external parts should be adapted to each movement. Furthermore, since the volume is already well optimized, it seems difficult to apply this method without affecting the watch's design. The solution involves modifying the internal volume of the case by transmitting the stroke to a moving mechanism such as a piston or similar movement.

[0068] Therefore, in an alternative embodiment specifically designed for aftermarket applications, the compensation device 10 includes a waterproof volume measuring device 5 that enables aftermarket technicians to modify the internal volume of the housing 2, and / or at least one waterproof gas injection or extraction conduit 6, and / or a controlled and instantaneous heating device 7 for increasing its internal temperature.

[0069] More specifically, the volume measuring device 5 includes a piston that is movable within the housing 2 and can be tightened and locked in place using special tools not provided to the user under the action of external micro-measuring control.

[0070] More specifically, during the manufacturing process in the factory, the internal volume of the shell 2 is modified by adjusting the stroke of at least one piston, which can be tightened and locked in place using special tools not provided to the user under external micro-measuring control.

[0071] More specifically, the waterproof gas injection or extraction conduit 6 can be locked in place using special tools not provided to the user.

[0072] More specifically, the thermal device 7 includes a device for converting light energy and / or a device for storing energy.

[0073] More specifically, during the preparation process in the factory, the gas or gas mixture contained in shell 2 is dried to reduce humidity H.

[0074] More specifically, during the preparation process in the factory, a dryer is inserted into the shell to fix the residual humidity H therein.

[0075] Finally, several effects (Ct, Cp, shell conditions, or changes in surface volume) can be combined simultaneously to achieve the desired purpose.

[0076] Generally, in order to minimize the effect of temperature on the table, it seems necessary to minimize the dispersion of Ct.

[0077] The invention further relates to a table 1 suitable for implementing the method, particularly in after-sales service. The waterproof table 1 includes a waterproof housing 2 containing a movement 3 itself, the movement 3 including a oscillator 4. The table 1 includes compensation devices 10, each capable of being locked in place using special tools not provided to the user. Each compensation device 10 includes a waterproof volume measuring device 5 enabling after-sales technicians to modify the internal volume of the housing 2, and / or at least one waterproof gas injection or extraction conduit 6, and / or a controlled and instantaneous heating device 7 for increasing its internal temperature.

Claims

1. A method for compensating for a rate that varies with temperature changes of a waterproof watch (1), wherein, Waterproof case (2) containing a movement (3) itself comprising an oscillator (4), said case (2) containing an internal volume V at the time of leaving the factory after initial rate setting, the internal volume V being occupied by n moles of a gas with constant R substantially complying with the ideal gas law, characterized in that the pressure coefficient Cp of the movement (3) is determined in the factory by measurement and / or calculation, so as to define a relative linear variation of the rate of the movement (3) as a function of the pressure P of the gas, in which the value of the humidity coefficient Ch of the movement (3) is determined in the factory after measurement and / or calculation, so as to define a maximum relative linear variation of the rate of the movement (3) as a function of the humidity H in the movement (3), in which an optimal value Cto of the thermal coefficient Ct of the oscillator (4) is calculated, so as to define a relative linear variation of the rate of the oscillator (4) as a function of the temperature T, said optimal value Cto being intended to compensate for the pressure and humidity deviations according to the following formula: - ， and in which, - said watch (1) is equipped, whether for after-sales applications or for packaging in the factory, with a compensation device (10) arranged to modify, inside the case (2), the pressure P and / or the properties of the gas and its constant R and / or the quantity of gas and its number of moles n and / or the temperature T, - or for preparation in the factory, by modifying the thickness of the oxide layer and / or applying a coating and / or by local ablation to modify the thermal coefficient of the elastic return means comprised in the oscillator (4), and / or modifying the number of moles of gas in the watch and / or the properties of the gas in the watch, and / or modifying the internal volume of the case (2).

2. The method of claim 1, wherein, The pressure P and / or the number of moles n are modified by modifying the pressure P before closing the case (2) and / or by changing the temperature T of the watch (1).

3. The method according to claim 1 or 2, characterized in that, The humidity coefficient Ch of the movement (3) is determined to the value zero, and in which the optimal value Cto of the thermal coefficient Ct of the oscillator (4) is calculated according to the following formula: - 。 4. The method according to claim 1 or 2, characterized in that, For after-sales applications, the compensation device (10) comprises waterproof volume measuring means (5) enabling an after-sales technician to modify the internal volume of the case (2), and / or at least one gas injection or extraction conduit (6), and / or thermal means (7) for a controlled and transient increase in the internal temperature.

5. The method of claim 4, wherein, The volume measuring means (5) comprise a piston that can be moved in the case (2) and that can be tightened and locked in place under the action of external micrometric control, using special tools not provided to the user.

6. The method of claim 4, wherein, The gas injection or extraction conduit (6) can be locked in place using special tools not provided to the user.

7. The method of claim 4, wherein, The thermal means (7) comprise means for converting light energy and / or means for storing energy.

8. The method of claim 1 or 2, wherein, The elastic return means of the oscillator (4) are made of silicon and / or silicon oxide, and in which, for preparation in the factory, the thermal coefficient of the elastic return means is modified by modifying the thickness of the silicon oxide layer.

9. The method of claim 1 or 2, wherein, Said elastic return means of said oscillator (4) are made in the form of thin elastic strips with the "LIGA" method, and wherein said thermal coefficient of said elastic return means included in said oscillator (4) is modified during the preparation in the factory by applying a coating and / or by local ablation.

10. The method of claim 1 or 2, wherein, Said elastic return means of said oscillator (4) are made in the form of thin elastic strips with the "LIGA" method, and wherein said thermal coefficient of said elastic return means included in said oscillator (4) is modified during the preparation in the factory by applying a coating and / or by local ablation.

11. The method of claim 1 or 2, wherein, During the preparation in the factory, the number of moles of gas in said table is modified by closing said case (2) at a pressure defined by calculation, making said rate of said table insensitive to temperature, or closing said case (2) at a temperature defined by calculation, making said rate of said table insensitive to temperature, and slowly cooling said case (2) after its closure.

12. The method of claim 1 or 2, wherein, During the preparation in the factory, the properties of the gas contained in said table are modified by exchanging said gas completely or partially with a new gas or gas mixture having another value of said constant R, said constant R being adapted to adjust said thermal coefficient Ct appropriately to make said rate of said table insensitive to temperature.

13. The method of claim 12, wherein, Said case (2) is sealed after said gas exchange to prevent any action by the user without special tools.

14. The method of claim 1 or 2, wherein, During the preparation in the factory, said internal volume of said case (2) is modified by adjusting the stroke of at least one piston that can be tightened and locked in place under the action of an external micrometric control with special tools not provided to the user.

15. The method of claim 1 or 2, wherein, During the preparation in the factory, said gas or gas mixture contained in said case (2) is dried to reduce the humidity H.

16. The method of claim 1 or 2, wherein, During the preparation in the factory, a desiccator is inserted into said case to fix the residual humidity H therein.

17. A waterproof watch (1), wherein The waterproof case (2) contains a movement (3) which itself comprises an oscillator (4), characterized in that said watch (1) comprises compensation means (10) each of which can be locked in place with special tools not provided to the user, said compensation means (10) comprising waterproof volume measuring means (5) enabling a post-sale technician to modify said internal volume of said case (2) according to the method of any one of claims 1 to 16, and / or at least one waterproof gas injection or extraction conduit (6), and / or thermal means (7) for a controlled and transient increase in the temperature of its interior.

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