JP2023157608A - sensor - Google Patents

Abstract

To prevent a detection element (for example, piezoelectric element) from being damaged by a simple user's operation when a sensor is carried.SOLUTION: A sensor 1 comprises: a piezoelectric element 4 for detection; a weight 5 movable between a contact position in which the piezoelectric element 4 is contacted and a separation position from which the piezoelectric element 4 is separated; and a stopper 3 movable between a fixation position at which the weight 5 is fixed in the separation position and a retreat position retreated from the fixation position. The stopper 3 includes a spring 3c, and a steel ball 3d arranged along the spring 3c, positioned closer to contact surface side of an enclosure 2 than the spring 3c, and in contact with the contact surface of the enclosure 2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sensor that detects vibrations.

In sensors that detect vibrations, for example, a piezo element that converts force applied to a piezoelectric body into voltage is used to detect vibrations. In conventional sensors for detecting vibrations, a compressive load is applied to the piezo element using a weight in order to increase the sensitivity of the piezo element. FIG. 9(a) is a cross-sectional view showing a conventional sensor. FIG. 9(b) is a diagram showing a piezo element. As mentioned above, a compressive load is applied to the piezo element by the weight, so if an impact is applied to the casing when carrying or moving the sensor, the weight may collide with the piezo element due to the impact. There is a possibility that the impact caused by a collision may lead to damage to the piezo element or a change in performance. Note that Patent Document 1 discloses an invention for preventing destruction of piezo elements (piezoelectric elements).

In order to solve the above-mentioned problem, the applicant has filed Japanese Patent Application No. 2021-109776. 10 and 11 are cross-sectional views showing a sensor of the invention according to Japanese Patent Application No. 2021-109776. The sensor 101 is placed, for example, on a road that is a measurement target, and detects (measures) vibrations generated on the road that is a measurement target.

The sensor 101 includes a housing 102 having a substantially cylindrical shape. The casing 102 accommodates a weight 105, etc., which will be described later. The housing 102 defines the outer shape of the sensor 101. Furthermore, a substantially cylindrical protrusion 102a that protrudes downward is provided on the lower surface (bottom surface) of the housing 102. Furthermore, a convex contact portion 102b is provided at the tip of the protrusion 102a for bringing the sensor 101 into contact with a measurement target (for example, a road). The vibration transmitted to the contact portion 102b is transmitted to the piezo element 104, which will be described later, so that the sensor 101 detects (measures) the vibration using the piezo element 104.

Further, from the lower surface (bottom surface) of the housing 102, legs 103 for supporting the sensor 101 extend in the vertical direction. The leg portions 103 can be expanded and contracted in the vertical direction, for example, and the sensor 101 can be stably installed on the road to be measured by the leg portions 103 being expanded and contracted in the vertical direction.

The piezo element 104 (detection element) is arranged inside the housing 102. Specifically, the piezo element 104 is arranged on the bottom surface (lower surface) within the protrusion 2a of the housing 2. Note that the shape of the piezo element 104 is similar to the piezo element shown in FIG. 9(b). That is, the piezo element 104 has a flat, substantially disk shape. A weight 105 is arranged above the piezo element 104 to apply a compressive load to the piezo element 104. The weight 105 is used to generate a voltage in the piezo element 104 by applying a compressive load. The weight 105 has, for example, a substantially cylindrical shape. The lower half or more of the weight 105 is located within the protrusion 102a, but the upper part of the weight 105 protrudes from the protrusion 102a. The piezo element 104 and the weight 105 are arranged side by side in the vertical direction, that is, in the direction of gravity. Specifically, the piezo element 104 and the weight 105 are arranged side by side in the direction of gravity so that the load of the weight 105 is applied to the piezo element 104.

A member 106 is arranged above the weight 105. The member 106 has, for example, a substantially cylindrical shape. The diameter of member 106 is larger than the diameter of weight 105.

The sensor 101 further includes a fixing member 107 for fixing the weight 105 to the member 106. The fixing member 107 has a substantially cylindrical first portion 107a and a substantially cylindrical second portion 107b having a smaller diameter than the base portion 107a. The second portion 107b extends from the first portion 107a in the direction in which the first portion 107a extends. A threaded portion 107c is provided at the tip of the second portion 107b.

The member 106 is provided with a through hole 106a through which the fixing member 107 is inserted. The through hole 106a has a shape corresponding to the outer shape of the fixing member 107. Further, the member 106 is provided with a holding hole 106b for holding the fixing member 107. A threaded portion 6c corresponding to the threaded portion 107c of the fixing member 107 is provided at the tip of the holding hole 106b.

The weight 105 is provided with an insertion hole 105a into which the second portion 107b of the fixing member 107 is inserted. A threaded portion 105b corresponding to the threaded portion 107c of the fixing member 107 is provided in a part of the insertion hole 105a.

In the invention related to Japanese Patent Application No. 2021-109776, the weight 105 can be fixed to the member 106 by the fixing member 107. In this case, the user inserts the fixing member 107 into the through hole 106a of the member 106, further inserts the fixing member 107 into the insertion hole 105a of the weight 105, and inserts the fixing member into the threaded part 105b of the insertion hole 105a of the weight 105. The weight 105 can be fixed to the member 106 by screwing together the screw portion 107c of the member 107.

If the weight 105 is not fixed to the member 106 using the fixing member 107, insert the fixing member 107 into the holding hole 106b of the member 106, and screw the threaded part 107c of the fixing member 107 into the threaded part 106c of the holding hole 106b. By holding the fixing member 107 in the holding hole 106b, it is possible to prevent the fixing member 107 from being lost.

Japanese Patent Application Publication No. 2010-230459

In the invention according to Japanese Patent Application No. 2021-109776, when the sensor 101 is used, the fixing member 107 (weight fixing screw) for lifting the weight 105 is arranged at the position shown in FIG. On the other hand, when carrying the sensor 101, the fixing member 107 is placed in the position shown in FIG. , so that the impact of the weight 105 is not applied directly. However, in the invention related to Japanese Patent Application No. 2021-109776, it is troublesome to tighten the fixing member 107 in terms of operation, and there is a possibility that the fixing member 107 may be lost when the fixing member 107 is removed. be.

An object of the present invention is to prevent a detection element (for example, a piezo element) from being damaged when the sensor is carried around due to a simple operation by a user.

The sensor of the first invention includes a detection element, a contact position in contact with the element, and a spaced position spaced apart from the element, a movable weight, and a fixed position that fixes the weight at the spaced position. , a retracted position retracted from the fixed position, and a movable stopper.

In the present invention, the stopper is movable between a fixed position in which the weight is fixed at a separate position separated from the detection element and a retracted position in which the weight is evacuated from the fixed position. Therefore, by moving the stopper to the fixed position when carrying the sensor, the user can use the stopper to fix the weight at a separate position away from the element. Therefore, according to the present invention, it is possible to prevent the detection element from being damaged when the sensor is carried around by a simple operation by the user.

The sensor of a second invention is the sensor of the first invention, further comprising a casing that houses the weight therein, and the stopper is movable between a fixed position and a retracted position on the casing. , the casing has a recess on a contact surface with the stopper, and the stopper is arranged in parallel with a biasing member and closer to the contact surface of the casing than the biasing member. and a ball that is located and contacts the contact surface of the casing.

In the present invention, the casing has a recess on the contact surface with the stopper. Further, the stopper has a ball that is arranged in line with the biasing member, is located closer to the contact surface of the housing than the biasing member, and comes into contact with the contact surface of the housing. As a result, when the user moves the stopper from the retracted position to the fixed position, the user can feel a click between the stopper's ball and the recessed part of the casing, making it possible for the user to recognize that the stopper has been moved. I can do it.

In the sensor of a third invention, in the sensor of the second invention, the stopper has a housing section extending in a direction perpendicular to the moving direction, and the biasing member and the ball are arranged inside the housing section. It is characterized by being contained.

The sensor of a fourth invention is the sensor of any one of the first to third inventions, wherein the stopper has a base extending in a direction parallel to the moving direction of the stopper, and the stopper has a base extending in a direction parallel to the moving direction of the stopper. , further comprising a rail for guiding the stopper to a fixed position and a retracted position, and the base has a boss projecting toward the rail.

In order to add a stopper for fixing the weight at a separate position away from the detection element and to make the stopper movable between the fixed position and the retracted position, a gap between the parts is required. Such a gap may become a source of unnecessary vibration during measurement by the sensor. In the present invention, the base of the stopper has a boss projecting toward the rail. As a result, when the stopper does not fix the weight at a fixed position, that is, when the sensor measures the weight, the boss presses the stopper against the rail, thereby preventing the stopper from vibrating. Therefore, vibrations are prevented from adversely affecting measurement, and highly reliable measurement is possible.

In the sensor of a fifth invention, in the sensor of the fourth invention, the boss is provided at a position where the stopper contacts the rail before separating from the weight when the stopper moves from the fixed position to the retracted position. It is characterized by being

If the user moves the stopper from a fixed position where the element is fixed, the weight may suddenly fall and damage the element. In the present invention, when the stopper moves from the fixed position to the retracted position, the boss is provided in a contact position with the rail before separating from the weight. As a result, the stopper is pressed down by the boss before it separates from the weight, thereby preventing the weight from falling suddenly.

A sensor of a sixth invention is the sensor of any one of the first to fifth inventions, in which the weight includes a weight main body, a supported part supported by the stopper, and a weight main body and the supported part. and a connecting portion for connecting.

In the sensor according to a seventh aspect of the invention, in the sensor according to the sixth aspect, a size of the supported part in a direction perpendicular to an extending direction of the connecting part is larger than the connecting part, and the stopper is It has a base extending in a direction perpendicular to the extending direction of the connecting portion, and a slit provided in the base, extending in the direction perpendicular to the extending direction of the connecting portion, and having a shape corresponding to the connecting portion. It is characterized by

In the present invention, the size of the supported portion in the direction perpendicular to the extending direction of the connecting portion is larger than the connecting portion. Moreover, the slit provided in the base of the stopper has a shape corresponding to the connection part of the weight. Therefore, at the fixed position of the stopper, when the connecting portion is located within the slit and the connecting portion and the inner wall of the slit are in contact with each other, the supported portion of the weight is supported by the base around the slit, and the weight is It is fixed at a spaced apart position away from the element.

In the sensor of an eighth aspect of the invention, in the sensor of the seventh aspect, the supported part is exposed to the outside of the casing in the extending direction of the connecting part, and the tip of the base is connected to the weight. is located at a contact position, faces the connecting portion and overlaps the supported portion in the extending direction of the connecting portion, and the tip of the slit has a shape corresponding to the outer shape of the supported portion. It is characterized by

In the present invention, the tip of the slit has a shape corresponding to the outer shape of the supported part. Therefore, since the stopper does not touch the weight, highly reliable measurement is possible.

A sensor according to a ninth invention is the sensor according to any one of the first to eighth inventions, wherein the element and the weight are arranged side by side in the direction of gravity, and the weight has a contact position and a separation position. It is characterized by being movable in a first direction parallel to the direction of gravity.

A sensor according to a tenth aspect of the present invention is the sensor according to the ninth aspect, wherein the stopper is movable between a fixed position and a retracted position in a second direction perpendicular to the first direction.

The sensor of the eleventh invention includes a detection element, a weight that is movable between a contact position where the element is contacted, and a spaced position that is spaced apart from the element, and a fixing member that fixes the weight at the spaced position. , comprising a switch that contacts the fixing member when the fixation of the weight by the fixing member is released, and a control unit that performs detection by the element when the switch is in contact with the fixing member. It is characterized by

In the present invention, the control unit performs detection using the element when the switch is in contact with the fixed member. As a result, detection by the element (sensor) is not performed in a state where the weight is not in contact with the element, thereby preventing proper data from being obtained.

A sensor according to a twelfth aspect of the invention is the sensor according to the eleventh aspect, wherein the control section does not perform detection by the element when the switch is not in contact with the fixing member.

A sensor according to a thirteenth invention is characterized in that in any one of the first to twelfth sensors, the element is a piezo element.

According to the present invention, it is possible to prevent the detection element from being damaged when the sensor is carried around by a simple operation by the user.

FIG. 1 is a cross-sectional view showing a sensor according to an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a sensor according to an embodiment of the present invention. 3 is an enlarged view of the vicinity of the stopper in FIG. 2. FIG. FIG. 3 is an enlarged perspective view of the vicinity of the stopper. FIG. 3 is an enlarged perspective view of the vicinity of the stopper. It is a flowchart which shows the processing operation of a sensor. It is a sectional view showing a sensor concerning a modification. It is a sectional view showing a sensor concerning a modification. (a) is a sectional view showing a conventional sensor. (b) is a diagram showing a piezo element. FIG. 2 is a sectional view showing a sensor according to the invention of Japanese Patent Application No. 2021-109776. FIG. 2 is a sectional view showing a sensor according to the invention of Japanese Patent Application No. 2021-109776.

Embodiments of the present invention will be described below. 1 and 2 are cross-sectional views showing a sensor 1 according to an embodiment of the present invention. The sensor 1 is placed, for example, on a road as a measurement target, and detects (measures) vibrations generated on the road as a measurement target. Hereinafter, the directions shown in the figures will be described as an up-down direction (gravitational direction) and a left-right direction (horizontal direction). Note that the shapes, dimensions, etc. of each part described below are merely examples, and can be changed as appropriate.

The sensor 1 includes a housing 2, a stopper 3, a piezo element 4, a weight 5, and the like. The casing 2 accommodates a weight 5, etc., which will be described later. The outer shape of the sensor 1 is configured by the housing 2. The housing 2 includes a housing body 2a and a lid body 2b. A substantially conical contact portion 2c for bringing the sensor 1 into contact with a measurement target (for example, a road) is provided on the lower surface (bottom surface) of the housing body 2a. The vibration transmitted to the contact portion 2c is transmitted to the piezo element 4, which will be described later, so that the sensor 1 detects (measures) the vibration using the piezo element 4. The housing body 2a is hollow inside and has a substantially cylindrical shape except for the contact portion 2c. The lid body 2b has a flat, substantially disk shape, and is placed on the housing body 2a. The lid body 2b is provided with a hole 2f for exposing a supported portion 5c of the weight 5, which will be described later, to the outside of the housing 2.

The piezo element 4 (detection element) is arranged inside the housing 2. Specifically, the piezo element 4 is arranged on the bottom surface (lower surface) inside the housing body 2a. Note that the shape of the piezo element 4 is similar to the piezo element shown in FIG. 9(b). That is, the piezo element 4 has a flat, substantially disk shape.

A weight 5 is arranged above the piezo element 4 to apply a compressive load to the piezo element 4. The weight 5 applies a compressive load to the piezo element 4, thereby generating a voltage in the piezo element 4. The piezo element 4 and the weight 5 are arranged side by side in the vertical direction, that is, in the direction of gravity (first direction). Inside the casing 2, the weight 5 moves the contact position shown in FIG. 1, where it is in contact with the piezo element 4, and the separated position shown in FIG. direction).

The weight 5 includes a weight main body 5a, a connecting portion 5b, a supported portion 5c, and a contact portion 5d. The weight body 5a has a substantially cylindrical shape. The supported portion 5c is a portion supported by the stopper 3. The supported portion 5c has a substantially cylindrical shape. The connecting portion 5b connects the weight main body 5a and the supported portion 5c, and extends in the vertical direction (direction of gravity). The connecting portion 5b has a substantially cylindrical shape. Here, the size of the supported part 5c in the direction (horizontal direction, horizontal direction) perpendicular to the extending direction (gravity direction, vertical direction) of the connecting part 5b is larger than that of the connecting part 5b. That is, the diameter of the supported portion 5c is larger than the diameter of the connecting portion 5b. The contact portion 5d is a portion that comes into contact with the piezo element 4, and protrudes downward from the weight body 5a.

The supported portion 5c of the weight 5 and a portion of the connecting portion 5b are exposed to the outside of the housing 2. Therefore, the user of the sensor 1 can lift the weight 5 from the contact position to the separated position by holding the supported part 5c.

When the weight 5 is located at the contact position shown in FIG. 1, a gap of 0.5 to 1.0 mm exists between the lower surface of the supported portion 5c and the upper surface of the lid body 2b. Further, when the weight 5 is located at the separated position shown in FIG. 2, a gap of 0.5 to 1.0 mm exists between the lower surface of the contact portion 5d and the upper surface of the piezo element 4.

The stopper 3 has two positions on the lid body 2b (casing 2): a fixed position where the weight 5 is fixed at a separate position where the weight 5 is separated from the piezo element 4 as shown in FIG. 2, and a retracted position from the fixed position shown in FIG. It is possible to move to the retracted position. That is, the stopper 3 fixes the weight 5 at a separated position where the weight 5 is separated from the piezo element 4. The stopper 3 is movable between a fixed position and a retracted position on the lid body 2b (casing 2) in a horizontal direction (second direction, left and right direction) perpendicular to the direction of gravity (first direction, up and down direction). .

FIG. 3 is an enlarged view of the vicinity of the stopper 3 in FIG. 2. 4 and 5 are enlarged perspective views of the vicinity of the stopper 3. The stopper 3 includes a wall 3a and a base 3b. The wall 3a is a portion extending in a direction (horizontal direction, left-right direction) of the stopper 3 and a direction perpendicular to it (gravitational direction, vertical direction). The base 3b is a portion extending in a direction parallel to the moving direction (horizontal direction, left-right direction). The wall 3a and the base 3b are in a substantially perpendicular relationship, and the stopper 3 has a substantially L-shape when viewed from the side.

The wall 3a has a hollow, substantially cylindrical housing portion 3i that bulges toward the base 3b. A spring 3c (biasing member) and a steel ball 3d are housed inside the housing portion 3i. The spring 3c and the steel ball 3d are arranged side by side in the direction of gravity (vertical direction). The steel ball 3d is located closer to the contact surface of the lid 2b (casing 2) than the spring 3c, and comes into contact with the contact surface of the lid 2b (casing 2). The screw 3e is screwed into the housing part 3i from above to below the housing part 3i. The spring 3c and the steel ball 3d remain inside the housing part 3i because the screw 3e is screwed into the housing part 3i. The inner wall of the accommodating portion 3i is threaded so that the screw 3e can be screwed into the inner wall.

Here, the lid body 2b (casing 2) is provided with a recess 2d (indentation) on the contact surface (upper surface) with the stopper 3. Therefore, when the stopper 3 moves on the lid 2b (casing 2), the steel ball 3d is moved in the vertical direction by the recess 2d and the flat part of the lid 2b, but by the spring 3c. When the stopper 3 is pressed against the lid 2b side, the user who moves the stopper 3 will feel a clicking sensation.

In addition, the contact surface (top surface) of the lid 2b (casing 2) with the stopper 3 is inclined downward from the top toward the outside (left side in FIGS. 1 and 2) from the center of the lid 2b. are doing. On the contrary, the contact surface (lower surface) of the base 3b of the stopper 3 with the lid 2b is inclined from the bottom to the top from the outside of the lid 2b (the left side in FIGS. 1 and 2) toward the center. ing. The inclination angle of the lid body 2b and the inclination angle of the base 3b match. When the stopper 3 moves from the retracted position to the fixed position, it also moves from below to above along the slope of the lid 2b.

Further, the base 3b of the stopper 3 is provided with a slit 3f. The slit 3f extends in a direction (horizontal direction, horizontal direction) perpendicular to the extending direction (gravitational direction, vertical direction) of the connecting portion 5b of the weight 5. Further, the slit 3f has a shape corresponding to the connecting portion 5b. The width of the slit 3f is approximately the same as the diameter of the connecting portion 5b of the weight 5. As described above, in the weight 5, the diameter of the supported portion 5c is larger than the diameter of the connecting portion 5b. Therefore, when the connecting part 5b is located in the slit 3 at the fixed position of the stopper 3 and the inner wall of the slit 3f contacts the connecting part 5b, the supported part 5c is supported by the base 3b around the slit 3f. By doing so, the weight 5 is fixed at a separate position away from the piezo element 4.

Further, the base 3b of the stopper 3 has a flange 3g extending in the width direction of the horizontal portion 3a. The collar 3g is a thinner portion than the base 3b. The collar 3g is provided on both sides of the base 3b in the width direction. A boss 3h projecting toward the rail 2e is provided on a surface (upper surface) of the collar 3g (base 3b) on the rail 2e side (described later). The boss 3h is provided at a position where the stopper 3 comes into contact with the rail 2e before separating from the weight 5 when the stopper 3 moves from the fixed position to the retracted position.

The above-mentioned rail 2e is provided on the top surface of the lid 2b (casing 2). The rail 2e is for guiding the stopper 3 to a fixed position where the weight 5 is fixed and a retracted position where it is retracted from the fixed position. The rail 2e extends in a direction parallel to the moving direction of the stopper 3 (horizontal direction, left-right direction). Two rails 2e are provided above the collar 3g, corresponding to the collar 3g. The stopper 3 is sandwiched between a rail 2e located above the collar 3g and the top surface of the lid 2b.

As described above, the supported portion 5c of the weight 5 is exposed to the outside of the housing 2 in the extending direction (gravitational direction, vertical direction) of the connecting portion 5b. Further, the tip of the base 3b faces the connecting portion 2b with the weight 5 at the contact position, and overlaps the supported portion 5c in the extending direction (gravity direction, vertical direction) of the connecting portion 5b. ing. The tip of the slit 3f has a shape corresponding to the outer shape of the supported portion 3c. That is, the tip of the slit 3f has a tapered shape so that the base 3b does not come into contact with the supported portion 5c.

In the invention related to Japanese Patent Application No. 2021-109776 shown in FIG. 10 and FIG. The weight 105 is kept in contact with the piezo element 104 when being carried. This has the purpose of protecting the piezo element 104. However, if the fixing member 107 is forgotten due to human error or the like and measurement is performed, the weight 105 is not in contact with the piezo element 104 and no load is applied to the piezo element 104. No data available.

In order to solve the problem of not being able to obtain proper data, the sensor 1 further includes a switch 6 in this embodiment. The switch 6 contacts the stopper 3 when the weight 5 is released from being fixed by the stopper 3 (fixing member). That is, the switch 6 contacts the stopper 3 as shown in FIG. 1 when the stopper 3 is in the retracted position. The switch 6 is turned on when the stopper 3 comes into contact with it. The sensor 1 further includes a microcomputer (control unit) not shown. The microcomputer performs detection (measurement) using the piezo element 4 when the switch 6 is in the on state, that is, when it is in contact with the stopper 3. On the other hand, the microcomputer does not perform detection (measurement) using the piezo element 4 when the switch 6 is in the off state, that is, when it is not in contact with the stopper 3.

When the switch 6 is on, that is, when it is in contact with the stopper 3, the stopper 3 does not fix the weight 5, so the weight 5 is in contact with the piezo element 4.

FIG. 6 is a flowchart showing the processing operation of the sensor 1. The microcomputer determines whether the piezo element 4 and the weight 5 are in contact with each other, that is, whether the switch 6 is on or not (S1). When the microcomputer determines that the piezo element 4 and the weight 5 are in contact, that is, the switch 6 is on (S1: Yes), it controls the sensor 1 to a state where it can start measurement (S2). On the other hand, if the microcomputer determines that the piezo element 4 and the weight 5 are not in contact, that is, the switch 6 is off (S1: No), it controls the sensor 1 to a state in which it is impossible to start measurement. (S3).

As described above, in this embodiment, the stopper 3 is movable between a fixed position in which the weight 5 is fixed at a spaced apart position from the piezo element 4, and a retracted position in which it is evacuated from the fixed position. Therefore, when the user carries the sensor 1, for example, by moving the stopper 3 to the fixed position, the user can fix the weight 5 at a separate position away from the piezo element 4 using the stopper 3. Therefore, according to the present embodiment, it is possible to prevent the piezo element 4 from being damaged when the sensor 1 is being carried around by a simple operation by the user.

Furthermore, in this embodiment, the housing 2 has a recess 2d on the surface that contacts the stopper 3. Further, the stopper 3 includes a steel ball 3d that is arranged side by side with the spring 3c, is located closer to the contact surface of the casing 2 than the spring 3c, and comes into contact with the contact surface of the casing 2. As a result, when the user moves the stopper 3 from the retracted position to the fixed position, the user can feel a click due to the steel ball 3d of the stopper 3 and the recess 2d of the housing 2, so the user can move the stopper 3. You can recognize what you have done.

In addition, a stopper 3 is added to fix the weight 5 at a separate position away from the piezo element 4, and in order to make the stopper 3 movable between the fixed position and the retracted position, a gap between the parts is required. . Such a gap may become a source of unnecessary vibration during measurement by the sensor 1. In this embodiment, the base 3b of the stopper 3 has a boss 3h that projects toward the rail 2e. As a result, when the stopper 3 does not fix the weight 5 at a fixed position, that is, when the sensor 1 measures, the stopper 3 is pressed against the side opposite to the rail 2e by the boss 3h, so vibration of the stopper 3 is prevented. Ru. Therefore, vibrations are prevented from adversely affecting measurement, and highly reliable measurement is possible.

Additionally, if the user moves the stopper 3 from the fixed position where the piezo element 4 is fixed, the weight 5 will suddenly fall, damaging the piezo element 4. there is a possibility. In this embodiment, the boss 3h is provided at a position where the stopper 3 comes into contact with the rail 2e before separating from the weight 5 when the stopper 3 moves from the fixed position to the retracted position. As a result, the stopper 3 is pressed down by the boss 3h before the stopper 3 separates from the weight 5, so that the weight 5 is prevented from falling suddenly.

Further, in the present embodiment, the size of the supported portion 5c in the direction perpendicular to the extending direction of the connecting portion 5b is larger than that of the connecting portion 5b. Furthermore, the slit 3f provided in the base 3b of the stopper 3 has a shape corresponding to the connecting portion 5b of the weight 5. Therefore, in the fixed position of the stopper 3, when the connecting part 5b is located in the slit 3f and the connecting part 5b and the inner wall of the slit 3f come into contact, the weight 5 is supported by the base 3b around the slit 3f. The portion 5c is supported, and the weight 5 is fixed at a spaced apart position from the piezo element 4.

Moreover, in this embodiment, the tip of the slit 3f has a shape corresponding to the outer shape of the supported part 5c. Therefore, since the stopper 3 does not touch the weight 5, highly reliable measurement is possible.

Further, in this embodiment, the microcomputer performs detection using the piezo element 4 when the switch 6 is in contact with the stopper 3. Thereby, detection by the piezo element 4 (sensor 1) is not performed in a state where the weight 5 is not in contact with the piezo element 4, so that it is possible to prevent proper data from being obtained.

Although the embodiments of the present invention have been described above, the forms to which the present invention can be applied are not limited to the above-described embodiments, and as illustrated below, as appropriate without departing from the spirit of the present invention. It is possible to make changes.

In the embodiment described above, the switch 6 comes into contact with the stopper 3 when the weight 5 is released from being fixed by the stopper 3 (fixing member). Instead of the stopper 3, for example, a screw may be used as the fixing member. 7 and 8 are cross-sectional views showing a sensor 201 according to a modification example in which a screw 203 is used as a fixing member. As shown in FIG. 7, the screw 203 is screwed into the weight 205 to fix the weight 5 at a position separated from the piezo element 4. Further, as shown in FIG. 8, when the weight 5 is released from being fixed by the screw 203, the weight 5 is located at a contact position where it contacts the piezo element 4.

As shown in FIG. 8, the switch 206 comes into contact with the screw 203 when the weight 205 is released from being fixed by the screw 203.

INDUSTRIAL APPLICATION This invention can be suitably adopted for the sensor which detects a vibration.

1, 201 Sensor 2 Housing 2a Housing body 2b Lid 2d Recess 3 Stopper (fixing member)
3a Wall 3b Base 3c Spring (biasing member)
3d Steel ball 3f Slit 3i Accommodating portion 4, 204 Piezo element (detection element)
5, 205 Weight 5a Weight body 5b Connection part 5c Supported part 6 Switch 203 Screw (fixing member)

Claims (13)

A detection element,
a weight that is movable between a contact position in contact with the element and a separate position away from the element;
a stopper that is movable between a fixed position in which the weight is fixed at a separated position and a retracted position in which the weight is evacuated from the fixed position;
A sensor characterized by comprising: further comprising a casing that houses the weight therein,
The stopper is movable between a fixed position and a retracted position on the housing,
The casing has a recess on a contact surface with the stopper,
The stopper is
a biasing member;
2. A ball disposed in parallel with the biasing member, located closer to the contact surface of the casing than the biasing member, and in contact with the contact surface of the casing. sensor. The stopper has a housing portion extending in a direction perpendicular to the moving direction,
The sensor according to claim 2, wherein the biasing member and the ball are housed inside the housing section. The stopper has a base extending in a direction parallel to the moving direction,
Further comprising a rail extending in a direction parallel to the moving direction of the stopper and guiding the stopper to a fixed position and a retracted position,
The sensor according to any one of claims 1 to 3, wherein the base has a boss projecting toward the rail. 5. The sensor according to claim 4, wherein the boss is provided at a position where the boss contacts the rail when the stopper moves from the fixed position to the retracted position before separating from the weight. The weight is
A weight body,
a supported part supported by the stopper;
The sensor according to any one of claims 1 to 5, further comprising a connecting part that connects the weight main body and the supported part. The size of the supported part in a direction perpendicular to the extending direction of the connecting part is larger than the connecting part,
The stopper is
a base extending in a direction perpendicular to the direction in which the connecting portion extends;
a slit provided in the base, extending in a direction perpendicular to the extending direction of the connecting portion, and having a shape corresponding to the connecting portion;
The sensor according to claim 6, characterized in that it has: The supported part is exposed to the outside of the casing in the extending direction of the connecting part,
The tip of the base faces the connecting portion and overlaps the supported portion in the extending direction of the connecting portion when the weight is located at the contact position,
8. The sensor according to claim 7, wherein the tip of the slit has a shape corresponding to the outer shape of the supported part. The element and the weight are arranged side by side in the direction of gravity,
The sensor according to any one of claims 1 to 8, wherein the weight is movable between a contact position and a separation position in a first direction parallel to the direction of gravity. The sensor according to claim 9, wherein the stopper is movable between a fixed position and a retracted position in a second direction perpendicular to the first direction. A detection element,
a weight that is movable between a contact position in contact with the element and a separate position away from the element;
a fixing member that fixes the weight at a separated position;
a switch that contacts the fixing member when the fixation of the weight by the fixing member is released;
a control unit that performs detection by the element when the switch is in contact with the fixing member;
A sensor characterized by comprising: The sensor according to claim 11, wherein the control unit does not perform detection by the element when the switch is not in contact with the fixing member. The sensor according to claim 1, wherein the element is a piezo element.

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