JP7092406B1 - Equipment with fasteners - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device provided with a fastening portion having a fastening force adjusting mechanism applicable to a small product, which can adjust the fastening force when a temperature change occurs and prevents the occurrence of a stick-slip phenomenon. SOLUTION: The device has a fastening portion having a first member, a second member, and a fastening member for fastening the first member and the second member, and the fastening member is A fastening force adjusting mechanism including a piezo element that expands and contracts by applying a voltage is provided, and the fastening force adjusting mechanism has a pressing force between the first member and the second member of a predetermined value or more. A device provided with a fastening portion that adjusts the fastening force of the fastening portion by applying a voltage to the piezo element. [Selection diagram] Fig. 2

Description

The present invention relates to a device having a fastening portion and having a fastening force adjusting mechanism.

When a temperature change occurs in the device due to the presence of heat-generating parts in the device to which a plurality of members are fastened or a large change in the outside air temperature, each member thermally expands or contracts. The amount of heat change (heat expansion amount or heat shrinkage amount) of each member depends on the amount of temperature change in the apparatus and the material constituting each member. Therefore, when there is a temperature difference between the fastened members, or when members of different materials are fastened even if there is no temperature difference, the amount of heat change between the fastened members due to the temperature change is applied. A difference is created, which causes thermal stress. Then, when the thermal stress in the plane direction is applied between the members to be fastened more than the frictional force due to the fastening force, a stick-slip phenomenon occurs and a noise is generated. The noise may be jarring at times, or even if there is no problem with the product, it may make the product user uneasy, which may reduce the product value. Therefore, from the viewpoint of improving the product value, various techniques for suppressing the stick-slip phenomenon and preventing noise have been developed so far.

Patent Document 1 discloses a method of suppressing a stick-slip phenomenon by providing a gap (clearance) in a portion where a change in thermal expansion or contraction is remarkable and limiting contact points between members.

Further, Patent Documents 2 and 3 disclose a method of suppressing a stick-slip phenomenon by eliminating a difference in thermal expansion between members by interposing a coating film containing a lubricant on the fastening surface.

Japanese Unexamined Patent Publication No. 9-147612 Japanese Unexamined Patent Publication No. 10-184447 JP-A-2002-163921

However, in the method described in Patent Document 1, since a gap is provided to limit the contact points between the members, the fastening force may be concentrated on the contact points to cause damage, or the fastening force of the entire device may decrease. rice field. In addition, the stick-slip phenomenon at the fastening points of the members may not be suppressed, and it may be difficult to apply the stick-slip phenomenon to products that cannot provide a gap, for example, shield parts.

In the method of interposing the coating film described in Patent Documents 2 and 3, when the temperature difference between the members to be fastened is large or the coefficient of thermal expansion (CTE) of the material constituting the member is large. In some cases, the stick-slip phenomenon could not be suppressed when the coefficients were significantly different.

Therefore, the development of new technology to prevent the occurrence of the stick-slip phenomenon is required, and since the miniaturization of products such as electronic devices has been progressing in recent years, the development of technology that can be applied to such small products is also required. Was sought after.

The present invention has been made in view of the above-mentioned problems, and provides a fastening force adjusting mechanism that can adjust the fastening force when a temperature change occurs, prevents the occurrence of the stick-slip phenomenon, and is applicable to small products. It is an object of the present invention to provide a device provided with a fastening portion having a fastening portion.

One aspect of the apparatus provided with the fastening portion of the present invention has a first member, a second member, and a fastening member for fastening the first member and the second member, and the fastening member. Is provided with a fastening force adjusting mechanism including a piezo element that expands and contracts by applying a voltage, and the fastening force adjusting mechanism has a pressing force between the first member and the second member of a predetermined value or more. At that time, by applying a voltage to the piezo element, the fastening force of the fastening portion is adjusted.

Further, one aspect of the device provided with the fastening portion of the present invention has a first member, a second member, and a fastening member for fastening the first member and the second member. The fastening member includes a fastening force adjusting mechanism including a piezo element that expands and contracts by applying a voltage, and the fastening force adjusting mechanism has a temperature difference between the first member and the second member of a predetermined value or more. At that time, by applying a voltage to the piezo element, the fastening force of the fastening portion is adjusted.

Further, one aspect of the device provided with the fastening portion of the present invention has a first member, a second member, and a fastening member for fastening the first member and the second member. The fastening member includes a fastening force adjusting mechanism including a piezo element that expands and contracts by applying a voltage, and the fastening force adjusting mechanism has a predetermined value at a temperature of at least one of the first member and the second member. When the above change occurs and the pressing force between the first member and the second member becomes a predetermined value or more, a voltage is applied to the piezo element to cause the fastening portion. It is characterized by adjusting the fastening force of.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a device provided with a fastening portion having a fastening force adjusting mechanism that can adjust the fastening force when a temperature change occurs, prevents the occurrence of a stick-slip phenomenon, and is applicable to small products. be able to.

It is a schematic sectional drawing which shows an example of the apparatus provided with a fastening part. It is a schematic partial sectional view which shows an example of the structure of the fastening part in the apparatus provided with the fastening part which concerns on this invention. FIG. 3 is a schematic partial cross-sectional view showing a state in which the fastening force of the fastening portion shown in FIG. 2 is released. It is a schematic partial sectional view which shows another example of the structure of the fastening part in the apparatus provided with the fastening part which concerns on this invention. FIG. 3 is a schematic partial cross-sectional view showing a state in which the fastening force of the fastening portion shown in FIG. 4 is released.

First, FIG. 1 shows a schematic cross-sectional view of an example of a device provided with a fastening portion. In FIG. 1, in the housing 100, a shield component whose material is a metal as a first member 101, a base plate whose material is a metal as a second member 102, and a fastening member 104 for fastening these members ( Devices with fasteners (bolts and nuts) are described. Then, in the device, the heat generating component 103 is arranged in the vicinity of the second member 102.

Here, for example, when the power of the apparatus is turned on while the device is placed in a cold region, the heat generating component 103 generates heat, and the temperature of the second member 102 first rises. At this time, since it takes time for the temperature to be transmitted to the first member 101, a temperature difference occurs between the first member 101 and the second member 102, and a sound due to the stick-slip phenomenon occurs between the two members. May occur. Further, when the linear expansion coefficients of the two members are significantly different, this phenomenon is more likely to occur.

However, in the device provided with the fastening portion according to the present invention (hereinafter, may be referred to as the present device), an actuator using a piezo element is incorporated in the fastening portion, and a voltage is applied to the piezo element to expand and contract the element. With, the fastening force of the fastening portion can be adjusted. Therefore, in this device, when a temperature change occurs in the device, more specifically, only while a thermal change (thermal expansion, etc.) of the member is occurring, the fastening force is reduced to reduce the fastening force of the fastening portion. It can make the plane slippery, suppress the stick-slip phenomenon, and prevent noise. In this way, in this device, the fastening force is adjusted (for example, small during thermal expansion) when the device is thermally changed so that the fastening member can slide without causing a stick-slip phenomenon, and the temperature is stable (for example, heat). After it has fully expanded), the fastening force can be restored again.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings are appropriately simplified.

<Device with fastening part>
As shown in FIG. 2, the present apparatus has a first member 1, a second member 2, and a fastening member for fastening the first member 1 and the second member 2. The fastening member includes a fastening force adjusting mechanism including a piezo element 5 that expands and contracts when a voltage is applied. Further, the fastening force adjusting mechanism applies a voltage to the piezo element 5 when the pressing force between the first member 1 and the second member 2 becomes a predetermined value or more, so that the fastening portion can be joined. Adjust the fastening force. As an example of the increase in the pressing force between the first member 1 and the second member 2, as described above, when a temperature difference occurs between the two members or the linear expansion coefficient of both members is large. If they are different, it is considered that the cause is that a difference occurs between the amount of thermal change (for example, the amount of thermal expansion and the amount of thermal contraction) of both members.

Therefore, the present device is a pressure measuring means (for example, a pressure gauge, etc.) for measuring a pressing force (fastening force) between the fastening portion, specifically, the first member 1 and the second member 2. ) (Not shown) can be placed. In the case of the embodiment as shown in FIGS. 2 and 4, between the first member 1 and the first shaft collar 4 or between the second member 2 and the second shaft collar 6. It is also possible to arrange the pressure measuring means by sandwiching it. Then, when the pressing force becomes a predetermined value or more, a voltage can be applied to the piezo element so that the value of the pressure measuring means becomes smaller than the predetermined value, and the fastening force of the fastening portion can be controlled.

Further, in the case of a device having a configuration in which a temperature difference occurs between the first member 1 and the second member 2, a temperature sensor or the like for measuring the temperature of the first member 1 and the second member 2 may be used. A temperature measuring means (not shown) can be provided. In such a configuration, the temperature difference between the two members greatly affects the pressing force between the two members. Therefore, when the temperature difference between the first member 1 and the second member 2 becomes a predetermined value or more, it is determined that the pressing force becomes a predetermined value or more, and the value of the pressure measuring means is a predetermined value. A voltage may be applied to the piezo element to control the fastening force of the fastening portion so as to be smaller. In this device, when applying a voltage to the piezo element, control may be performed after checking both the temperature difference and the pressing force of both members.

In this device, a temperature change of a predetermined value (temperature) or more is detected by the temperature measuring means on at least one of the first and second members, and the pressing force between the two members measured by the pressure measuring means is predetermined. When the value is equal to or higher than the value, a voltage may be applied to the piezo element to control the fastening force of the fastening portion. Here, the stick-slip phenomenon is considered to occur when a pressing force of a certain value or more and a deviation in the plane direction (lateral direction) are combined. For this reason, first, after detecting the deviation in the plane direction by detecting the temperature change, a voltage is applied to the piezo element when the pressing force is equal to or more than a predetermined value, and the fastening force is controlled to more reliably stick. The slip phenomenon can be suppressed.

The specific temperature difference (° C.) between the first member 1 and the second member 2 and the temperature change amount (° C.) of both members when the fastening force adjusting mechanism operates are determined by the applicable device. It can be appropriately set depending on the intended use and the occurrence status of the stick-slip phenomenon (sounding), and is not particularly limited. Therefore, the predetermined values for the temperature difference and the temperature change can be appropriately set within the range in which the effect of the present invention can be obtained.
Further, the predetermined value of the pressing force and the control value of the fastening force when the fastening force adjusting mechanism is operated are also effective in the present invention depending on the application of the applied device and the occurrence of the stick-slip phenomenon (sounding). It can be appropriately set within the obtained range, and is not particularly limited. However, when the fastening force between the members becomes completely zero and the fastening is released, between the first member 1 and the second member 2 and between the second member 2 and the second shaft collar 6. As shown in FIGS. 3 and 5, a gap A may occur in the space or the like. Therefore, even if a temperature change occurs in the device and thermal expansion of the member occurs, the fastening force at the fastening portion is not completely released but is weakened (the fastening force is reduced). It is preferable to suppress the stick-slip phenomenon. By applying such a control method, the fastening force of the entire device can be maintained, and the present invention can be applied to various devices such as electronic devices, lighting fixtures, and sealing parts.

As described above, this device is equipped with a tightening force adjusting mechanism using a piezo element, and when a temperature change occurs in the device, it is generated by the difference in temperature and the coefficient of linear expansion between the fastened members. It is possible to prevent the noise caused by the stick-slip phenomenon.

2 to 5 show a schematic partial cross-sectional view for explaining the structure of the fastening portion in the present device, more specifically, the operation of the fastening force adjusting mechanism using the piezo element. Here, FIGS. 2 and 4 are views showing a fastening state of the first member and the second member in the two embodiments of the present apparatus, and FIGS. 3 and 5 are views of two embodiments of the present apparatus. It is a figure which shows the state which the fastening of the 1st member and the 2nd member is released (the fastening force is zero) in the above.

In the apparatus shown in FIG. 2, the fastening member includes a countersunk shaft 3, a first shaft collar 4, a second shaft collar 6 with a bottom surface portion 6a, and a cylindrical piezo element 5. In addition to this, the fastening member may have a spring portion 7, a spring restraint 8, and an application line 11. Here, the shaft 3 with a dish includes a shaft portion 3a penetrating the fastening portion between the first member 1 and the second member 2, and a dish portion 3b arranged on the side of the first member.

Further, the first shaft collar 4 is for fixing between the first member 1 and the dish portion 3b, is arranged on the first member side, and has, for example, a cylindrical shape. In this way, a cylindrical first shaft collar 4 is bitten between the dish portion 3b of the dished shaft 3 and the first member 1. The material constituting the first shaft collar 4 preferably has a coefficient of linear expansion close to that of the material constituting the cylindrical piezo element 5 from the viewpoint of suppressing the stick-slip phenomenon.

Further, the second shaft collar 6 is fixed between the second member 2 and the shaft portion 3a, is arranged on the second member side, and has a bottom surface portion 6a. The shaft portion 3a is fixed by being in contact with the bottom surface portion 6a. More specifically, the countersunk shaft 3 is inserted into a through hole (a hole for fastening) of the first member 1 and the second member 2, and has a bottom surface portion so as to be in contact with the second member 2. The attached second shaft collar 6 is inserted into the countersunk shaft 3. The material constituting the second shaft collar 6 preferably has a coefficient of linear expansion close to that of the material constituting the cylindrical piezo element 5 from the viewpoint of suppressing the stick-slip phenomenon.

Further, the second shaft collar 6 is pressed by the spring portion 7 (spring). The spring portion 7 is suppressed by the spring restraint 8, and the spring restraint 8 is fixed to the countersunk shaft 3. The spring portion 7 makes the second shaft collar 6 movable in the axial direction of the countersunk shaft 3.

The piezo element 5 is arranged between the dish portion 3b and the bottom surface portion 6a along the axial direction of the countersunk shaft 3 and penetrates the fastening portion, and the shape thereof is, for example, a cylinder.

As the piezo element 5, an element whose thickness direction (axial direction of the countersunk shaft) shrinks when a voltage is applied may be used, or when a voltage is applied, the dimension in the thickness direction becomes smaller. A stretchable material may be used. For example, in the fastening portion shown in FIG. 2, instead of providing the cylindrical piezo element 5, the first shaft collar 4, and the spring portion, the dimensions are increased by applying a voltage between the countersunk portion 3b and the first member 1. By arranging a shrinking piezo element and applying a voltage during thermal expansion of the member, the fastening force of the fastening portion may be weakened. However, in this configuration, the piezo element is always subjected to the fastening compressive force during normal fastening when no voltage is applied. On the other hand, when a piezo element whose dimension is increased by applying a voltage is used, as shown in FIGS. 2 and 4, when no voltage is applied, the piezo element 5 is between the other member (here, the bottom surface portion 6a). There is a gap C, and the fastening compressive force is not applied to the piezo element. Therefore, from the viewpoint of the fatigue strength of the piezo element, it is preferable to use a piezo element whose size is increased by applying a voltage, in which pressure is applied only when a voltage is applied and the time for which the pressure is applied is limited.

Here, the gap C is the distance from the back surface of the dish portion 3b (the surface on the first member side) to the front surface of the bottom surface portion 6a (the surface on the second member side) in the fastening portion shown in FIG. It is obtained by subtracting the axial thickness (dimensions) of the cylindrical piezo element from (length). On the other hand, in the fastening portion shown in FIG. 4, the dimension obtained by subtracting the total thickness of the third shaft collar 9 and the cylindrical piezo element 5 from the distance from the back surface of the dish portion to the front surface of the bottom surface portion. In the embodiment shown in FIGS. 2 and 4, the dimension of the piezo element is expanded in the axial direction by applying a voltage, so that the fastening force of the fastening portion is adjusted (weakened), so that the gap C is not applied when the voltage is not applied. It is preferable to adjust the dimensions of each member so that

The application line 11 is for applying a voltage to the cylindrical piezo element 5, and is connected to a power supply circuit (not shown) through a through hole included in the second shaft collar 6.

Further, as shown in FIG. 4, a third shaft provided with a heating means 10 such as a heating heater between the dish portion 3b and the cylindrical piezo element 5 along the axial direction of the dished shaft 3. Color 9 (inner shaft color) may be arranged. Specifically, when the first member 1 and the second member 2 are fastened, the cylindrical piezo element 5 and the third shaft collar 9 are arranged through the shaft portion 3a of the countersunk shaft 3. do. Here, the third shaft collar 9 may be made of a material having a linear expansion coefficient higher than that of the materials constituting the first member 1 and the second member 2, from the viewpoint of suppressing the stick-slip phenomenon. preferable. A heating means 10 is wound around the third shaft collar 9, and the heating means 10 is connected to a power supply circuit (not shown) through a hole 12 of the dish portion 3b of the dished shaft 3. ..

Next, the fastening force adjusting mechanism in this apparatus will be described in more detail with reference to the drawings showing the fastening state (initial state) of the fastening portions of FIGS. 2 and 4.
As described above, a gap having a length C is provided between the cylindrical piezo element 5 and the bottom surface portion 6a of the second shaft collar 6 with a bottom surface portion when no voltage is applied. When a voltage is applied to the cylindrical piezo element 5 in this state, the dimension of the cylindrical piezo element 5 in the thickness direction is increased. In this device, when adjusting the fastening force to suppress the stick-slip phenomenon, the fastening force is only weakened and not completely released. However, in order to make it easier to understand the change in the thickness of each member including the cylindrical piezo element 5 due to the application of voltage, a voltage was applied in FIGS. 3 and 5 to completely release the fastening of the fastening portion. The figure of the state is shown. Here, the elongation of the cylindrical piezo element 5 is designated as a reference numeral B. When the extension B exceeds the length of the gap C, the spring portion 7 is pushed down, a gap A is formed as shown in FIG. 3, and the fastening of the fastening portion is released. In this device, a voltage is applied to the cylindrical piezo element 5 within the range in which the fastening of the fastening portion is not released. The gap A is represented by the following equation (1).
Gap A = Elongation B-Gap C formula (1)

Here, since this device is supposed to be used in an environment where temperature changes occur, dimensional changes occur due to thermal expansion or contraction of other members other than the cylindrical piezo element 5 due to temperature changes. It may happen. The elongation of the piezo element when a voltage is applied depends on the applied voltage, but is usually on the order of 0.1% of the original length in the case of an applied voltage of around 150 V. On the other hand, the coefficient of linear expansion (CTE), which is a characteristic value of thermal expansion of a material, varies depending on the material, but is on the order of about 0.001 to 0.01%. The elongation due to thermal expansion is expressed by the following equation (2).
Elongation due to thermal expansion = original length x CTE x temperature change equation (2)

If the temperature change in the device is within the range of several degrees Celsius, the elongation of each member due to thermal expansion is negligible with respect to the elongation of the piezo element, but when the temperature changes from several tens of degrees Celsius to several hundreds of degrees Celsius. , May not be negligible. As described above, when the thermal expansion of each member (first and second members, first and second shaft collars) due to the temperature change in the apparatus is not negligible, heating is performed as shown in FIG. It is preferable to arrange the third shaft collar 9 provided with the means 10 in the apparatus.
Hereinafter, the fastening portion shown in FIG. 4 will be described in detail. In order to make it easier to understand the thermal expansion of each member in the fastening portion, FIG. 5 shows a diagram showing a state in which the fastening portion shown in FIG. 4 is released from fastening.

In FIG. 5, the elongation of the first member 1 and the second member 2 due to thermal expansion is indicated by reference numeral F, the elongation of the third shaft collar 9 is indicated by reference numeral D, and the elongation of the first shaft collar 4 is indicated by reference numeral E. The extension of the second shaft collar 6 with the bottom surface is designated as the reference numeral G. Then, when the elongation of each member due to the thermal expansion is taken into consideration, the gap A is represented by the following equation (3). In the embodiment shown in FIG. 3, the reference numeral D is not taken into consideration in the following equation (3).
Gap A = Elongation (B + D) -Elongation (E + F + G) -Gap C formula (3)

Here, since the CTE of the cylindrical piezo element 5 is a low value, it is not included in the above calculation, and the elongation B is only the elongation due to the application of voltage. As described above, if the CTE of the first shaft collar 4 and the second shaft collar 6 with the bottom surface is close to (low value) the CTE of the cylindrical piezo element 5, the gap A is as follows. It is represented by (4).
Gap A = Elongation (B + D) -Elongation F-Gap C (4)

Here, since the third shaft collar 9 is arranged with a gap between the first member 1 and the second member 2, the temperature of the third shaft collar 9 is increased even when the temperature of these members rises. However, there is a possibility that the elongation D of the third shaft collar 9 becomes extremely small. In such a case, the elongation D can be adjusted by individually heating the third shaft collar 9 with the heating heater 10.

The CTEs of the first member 1 and the second member 2 and the third shaft collar 9 are close to each other, and the thickness dimension of the first and second members is that of the third shaft collar 9. If it is equal to the axial dimension, the following can be said. That is, if the temperature of the third shaft collar 9 is made equal to the average temperature of the first and second members, the elongation A is represented by the formula (1). Further, even when these dimensions are not equal, the gap A is represented by the equation (1) by appropriately adjusting the heating temperature of the third shaft collar 9.

In this way, by appropriately adjusting the voltage applied to the cylindrical piezo element and, if necessary, the heating temperature of the third shaft collar 9, the fastening force of the fastening portion can be controlled to a desired value. ..

As described above, the present device makes it possible to freely adjust the fastening force and suppress the noise caused by the stick-slip phenomenon that occurs when the temperature changes.

Furthermore, by controlling the tightening force as weakly as possible during expansion, it is possible to weaken the restraint in the sliding direction, and it is also possible to suppress the warpage of each member caused by the difference in the linear expansion coefficient when the temperature changes. can.

The present invention can be applied to all devices having fastening points (for example, electronic devices). Further, the present invention can be easily applied even to a small device having a product size of about 100 to 200 mm.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

1, 101 1st member 2, 102 2nd member 3 Plated shaft 3a Shaft part 3b Plate part 4 1st shaft collar 5 Piezo element 6 2nd shaft collar 6a Bottom part 7 Spring part 8 Spring restraint 9th 3 shaft collar 10 heating means 11 application line 12 hole 100 housing 103 heat generating part 104 fastening member

Claims (7)

The first member and
The second member and
A device having a fastening portion having the first member and a fastening member for fastening the second member.
The fastening member includes a fastening force adjusting mechanism including a piezo element that expands and contracts when a voltage is applied.
The fastening force adjusting mechanism applies a voltage to the piezo element when the pressing force between the first member and the second member becomes a predetermined value or more, so that the fastening portion can be joined. Has a configuration that adjusts the fastening force,
The fastening member
A shaft with a dish including a shaft portion penetrating the fastening portion between the first member and the second member, and a dish portion arranged on the side of the first member.
A first shaft collar arranged on the first member side, which is fixed between the first member and the dish portion, and
A second shaft collar with a bottom surface, which is arranged on the side of the second member and is fixed between the second member and the shaft portion.
A cylindrical piezo element arranged between the dish portion and the bottom surface portion along the axial direction of the countersunk shaft and penetrating the fastening portion.
A device with a fastening portion, characterized in that it has a fastening portion. The device provided with the fastening portion according to claim 1, wherein the piezo element adjusts the fastening force of the fastening portion by expanding its dimensions when a voltage is applied. The device provided with the fastening portion according to claim 1 or 2, further comprising a temperature measuring means for measuring the temperature of the first member and the second member. One of claims 1 to 3, wherein a third shaft collar provided with a heating means is arranged between the dish portion and the cylindrical piezo element along the axial direction of the shaft with a dish. A device with the fasteners described in. The apparatus provided with the fastening portion according to any one of claims 1 to 4 , wherein the fastening member further includes a spring portion that enables the second shaft collar to move in the axial direction of the countersunk shaft. .. The first member and
The second member and
A device having a fastening portion having the first member and a fastening member for fastening the second member.
The fastening member includes a fastening force adjusting mechanism including a piezo element that expands and contracts when a voltage is applied.
The fastening force adjusting mechanism applies a voltage to the piezo element when the temperature difference between the first member and the second member becomes a predetermined value or more, so that the fastening force of the fastening portion is fastened. Has a configuration to adjust,
The fastening member
A shaft with a dish including a shaft portion penetrating the fastening portion between the first member and the second member, and a dish portion arranged on the side of the first member.
A first shaft collar arranged on the first member side, which is fixed between the first member and the dish portion, and
A second shaft collar with a bottom surface, which is arranged on the side of the second member and is fixed between the second member and the shaft portion.
A cylindrical piezo element arranged between the dish portion and the bottom surface portion along the axial direction of the countersunk shaft and penetrating the fastening portion.
A device with a fastening portion, characterized in that it has a fastening portion. The first member and
The second member and
A device having a fastening portion having the first member and a fastening member for fastening the second member.
The fastening member includes a fastening force adjusting mechanism including a piezo element that expands and contracts when a voltage is applied.
In the fastening force adjusting mechanism, the temperature of at least one of the first member and the second member changes by a predetermined value or more, and the first member and the second member It has a configuration in which the fastening force of the fastening portion is adjusted by applying a voltage to the piezo element when the pressing force between them exceeds a predetermined value.
The fastening member
A shaft with a dish including a shaft portion penetrating the fastening portion between the first member and the second member, and a dish portion arranged on the side of the first member.
A first shaft collar arranged on the first member side, which is fixed between the first member and the dish portion, and
A second shaft collar with a bottom surface, which is arranged on the side of the second member and is fixed between the second member and the shaft portion.
A cylindrical piezo element arranged between the dish portion and the bottom surface portion along the axial direction of the countersunk shaft and penetrating the fastening portion.
A device with a fastening portion, characterized in that it has a fastening portion.

Images