Load sensor

Abstract

To provide a load sensor capable of suppressing a decrease in detection accuracy.SOLUTION: A load sensor 1 includes: a driven member 11 which is connected to a movable member 2 and is movable along a first direction D1 as the movable member 2 moves in the first direction D1; a first sensor element 12 moving as the driven member 11; an attachment member 13 for attaching the first sensor element 12 to the driven member 11; a second sensor element 14 which is attached unmovably to a base part 3 and mutually interacts with the first sensor element 12; and a guide part 15 which guides the first sensor element 12 along a prescribed route so that the first sensor element 12 moves in a prescribed relation relative to the second sensor element 14. The attachment member 13 has a displacement part 131 displaceable in the direction perpendicular to the first direction D1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a load sensor.

Background Art

[0002] In a drive device such as an electric parking brake device, a load sensor is used to detect the drive load of a drive target. The load sensor includes, for example, a magnet and a Hall IC as disclosed in Patent Document 1. The load sensor detects the drive load of the drive target based on the positional relationship between the magnet and the Hall IC.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a drive device having a plurality of components, due to play between components or displacement of the mounting position of components during driving of the drive device, the Hall IC may be displaced relative to the magnet, resulting in a decrease in detection accuracy.

[0005] Therefore, an object of the present invention is to provide a load sensor capable of suppressing a decrease in detection accuracy.

Means for Solving the Problems

[0006] The load sensor of the present invention is a load sensor that detects that a load equal to or greater than a predetermined value is applied to a moving member that moves in a first direction with respect to a base in a driving device, the load sensor including: a driven member connected to the moving member and movable along the first direction as the moving member moves in the first direction; a first sensor element that moves together with the driven member; a mounting member for attaching the first sensor element to the driven member; a second sensor element that is fixedly attached to the base of the driving device and interacts with the first sensor element; and a guide portion that guides the first sensor element along a predetermined path so that the first sensor element moves in a predetermined positional relationship with respect to the second sensor element, the mounting member having a displacement portion displaceable in a direction perpendicular to the first direction.

Advantages of the Invention

[0007] According to the load sensor of the present invention, it is possible to suppress a decrease in detection accuracy.

Brief Description of the Drawings

[0008]

Figure 1

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, a load sensor according to an embodiment of the present invention will be described. Note that the following embodiments are merely examples, and the load sensor of the present invention is not limited to the following embodiments.

[0010] In this specification, expressions such as "perpendicular to A" and similar expressions do not refer only to a direction that is completely perpendicular to A, but include a direction that is substantially perpendicular to A. Also, in this specification, expressions such as "parallel to B" and similar expressions do not refer only to a direction that is completely parallel to B, but include a direction that is substantially parallel to B. Further, in this specification, expressions such as "C shape" and similar expressions do not refer only to a complete C shape, but include a shape that reminds one of a C shape visually (substantially C shape).

[0011] As shown in FIGS. 1 and 2, the load sensor 1 of the present embodiment detects that a load equal to or greater than a predetermined value is applied to the moving member 2 in a driving device DR including the moving member 2 that moves in the first direction D1 with respect to the base 3.

[0012] The driving device DR in which the load sensor 1 is provided moves the moving member 2 in the first direction D1. In the present embodiment, when the moving member 2 moves in the first direction D1, a predetermined driving target O (see FIG. 1) is driven. The configuration of the driving device DR is not particularly limited as long as it can drive a predetermined driving target O by moving the moving member 2 in the first direction D1. In the present embodiment, as shown in FIG. 1, the driving device DR includes a base 3 that supports the moving member 2 so as to be movable in the first direction D1, the moving member 2, the load sensor 1, a driving unit 4 that generates a driving force for moving the moving member 2, and a transmission unit 5 that transmits the driving force of the driving unit 4 to the moving member 2. In the present embodiment, in the driving device DR, when the driving unit 4 operates, the driving force of the driving unit 4 is transmitted to the moving member 2 via the transmission unit 5. As a result, the moving member 2 moves in the first direction D1, and a predetermined driving target O is driven (via a long member 7 described later).

[0013] The use of the drive device DR is not particularly limited as long as it can drive a predetermined drive target O by moving the moving member 2 in the first direction D1. In the present embodiment, the drive device DR is an electric parking brake device that drives a brake mechanism (drive target O) such as a brake shoe. The drive target O is a brake mechanism in the present embodiment, but is not particularly limited as long as it is a target directly or indirectly driven by the drive device DR. The structure of the drive device DR is not particularly limited as long as it can drive a predetermined drive target O by moving the moving member 2 in the first direction D1. In the present embodiment, as shown in FIG. 1, the drive device DR further includes a long member 7 connected to the moving member 2 via a connecting member 6. As shown in FIGS. 1 and 2, one end of the long member 7 is connected to the connecting member 6, and the other end of the long member 7 is connected to the drive target O. The drive target O is operated by the long member 7 operated by the moving member 2. In the present embodiment, the long member 7 is a flexible cable (inner cable of a control cable), but the long member may be a long member other than a cable, such as a rod. The drive device DR may have a structure in which the moving member 2 and the drive target O are directly connected without having the long member 7 connected to the moving member 2.

[0014] In this specification, the first direction D1 is the moving direction of the moving member 2 with respect to the base 3. In the present embodiment, the first direction D1 is the same direction (parallel direction) as the direction of the axis X (see FIGS. 1 and 2) of the axially extending moving member 2. Note that in this specification, one of the directions in which the moving member 2 moves is referred to as one side of the first direction D1, and the opposite direction is referred to as the other side of the first direction D1. In the present embodiment, one side of the first direction D1 is the direction in which the moving member 2 moves when the driving target O is driven (in the present embodiment, the right side in FIGS. 1 and 2), and the other side of the first direction D1 is the direction opposite to the direction in which the moving member 2 moves when the driving target O is driven (in the present embodiment, the left side in FIGS. 1 and 2). Also, the direction in which the first sensor element 12 and the second sensor element 14 described later face each other is referred to as the second direction D2. In the present embodiment, the second direction D2 is one of the directions perpendicular to the first direction D1 (the radial direction of the moving member 2) (including the direction approaching and separating from the moving member 2). More specifically, the second direction D2 is the direction in which the axis X of the moving member 2 and the first sensor element 12 described later are separated from each other (the vertical direction in FIG. 2) among the directions perpendicular to the first direction D1 (the radial direction of the moving member 2). Also, the direction perpendicular to both the first direction D1 and the second direction D2 is referred to as the third direction D3 (the vertical direction in FIG. 1).

[0015] As shown in FIG. 1, the base 3 supports part or all of the constituent members of the driving device DR, such as the load sensor 1, the moving member 2, the driving part 4, the transmission part 5, and the connecting member 6. The shape and structure of the base 3 are not particularly limited as long as they can support the constituent members of the driving device DR. In the present embodiment, the base 3 is a casing that houses the constituent members of the driving device DR. More specifically, the base 3 is a casing that houses the load sensor 1, the moving member 2, the driving part 4, the transmission part 5, and the connecting member 6 inside. The structure of the base 3 is not particularly limited, but in the present embodiment, the base 3 includes a first casing (the lower casing in FIG. 2) that is one half on one side in the second direction D2 and a second casing (the upper casing in FIG. 2) that is the other half on the other side in the second direction D2.

[0016] In the present embodiment, as shown in FIG. 1, the base 3 includes a sensor housing portion 31 in which the load sensor 1 is housed, a drive unit housing portion 32 in which the drive unit 4 is housed, a movement path 33 along which the connection member 6 is guided and the moving member 2 moves, and a lead-out portion 34 through which the long member 7 is led out to the outside of the base 3. In the present embodiment, in the movement path 33, the moving member 2 and the connection member 6 are housed so as to be movable in a first direction D1 with respect to the base 3. Further, in the sensor housing portion 31, a driven member 11 (to be described later) of the load sensor 1 is housed so as to be movable in the first direction D1 with respect to the base 3.

[0017] The drive unit 4 generates a driving force for moving the moving member 2. More specifically, the drive unit 4 generates a driving force for moving the moving member 2 in order to drive the drive target O. In the present embodiment, due to the driving force of the drive unit 4, as will be described later, when the second moving member 22 rotates, as shown in FIGS. 2 to 4, the first moving member 21 relatively moves in one direction of the first direction D1 with respect to the second moving member 22 (and the base 3). When the first moving member 21 relatively moves in the first direction D1 with respect to the second moving member 22, the connection member 6 moves in one direction of the first direction D1. By the movement of the connection member 6 in one direction of the first direction D1, the long member 7 is operated in one direction of the first direction D1 and the drive target O is driven.

[0018] In the present embodiment, the drive unit 4 includes a motor 41. The motor 41 is configured to be capable of rotating forward and backward, and can rotate the second moving member 22 in one rotational direction and the other rotational direction about the axis X. The motor 41 is connected to the transmission unit 5 via a speed reduction mechanism.

[0019] The transmission unit 5 transmits the driving force of the driving unit 4 that moves the moving member 2 in the first direction D1 to the moving member 2. The structure of the transmission unit 5 is not particularly limited as long as it can transmit the driving force of the driving unit 4 to the moving member 2. The transmission unit 5 includes, for example, a driving force transmission member such as one or more gears. In the present embodiment, as shown in FIG. 2, the driving force transmission member of the transmission unit 5 includes a fitting member 51 that fits into the second moving member 22. In the present embodiment, the fitting member 51 fits with the second moving member 22 so as to rotate the second moving member 22 around the axis X and to allow the second moving member 22 to move in the first direction D1 with respect to the fitting member 51. Specifically, as shown in FIGS. 2 to 4, the fitting member 51 is arranged coaxially with the second moving member 22 and engages with the outer periphery of the second moving member 22 around the axis X. Thereby, when the fitting member 51 rotates around the axis X, the second moving member 22 also rotates, and the second moving member 22 is relatively movable in the first direction D1 with respect to the fitting member 51 (see FIGS. 3 and 4). The structure of the fitting member 51 is not particularly limited. In the present embodiment, the fitting member 51 is a gear rotatably supported by the base 3 via a bearing B. In the present embodiment, when the driving force of the driving unit 4 is transmitted to the fitting member 51 via driving force transmission members such as a plurality of gears, the fitting member 51 rotates around the axis X of the second moving member 22, and the second moving member 22 is rotated around the axis X. As a result, although details will be described later, the first moving member 21 whose rotation around the axis X is restricted relatively moves in one direction in the first direction D1 with respect to the second moving member 22 from the state shown in FIG. 2 to the state shown in FIG. 3.

[0020] The connecting member 6 connects the moving member 2 and the long member 7. In the present embodiment, as shown in FIGS. 1 and 2, the connecting member 6 is connected to the other end of the first moving member 21 in the first direction D1. Further, the connecting member 6 is connected to one end of the long member 7 in the first direction D1. In the present embodiment, the connecting member 6 is configured to restrict the rotation of the first moving member 21 about the axis X. Specifically, the connecting member 6 is configured to engage with the base 3 in the direction about the axis X in the movement path 33 of the base 3, and the first moving member 21 is connected to the connecting member 6 so as to engage with it in the direction about the axis X. Thereby, as will be described later, the first moving member 21 screwed to the second moving member 22 is suppressed from rotating about the axis X when the second moving member 22 rotates about the axis X, and moves in one direction in the first direction D1 with respect to the second moving member 22 without rotating about the axis X. Note that the connecting member 6 may be integrally provided at the other end of the first moving member 21 in the first direction D1.

[0021] The moving member 2 moves in the first direction D1 with respect to the base 3. In the present embodiment, as shown in FIG. 2, one side of the moving member 2 in the first direction D1 is connected to the load sensor 1 (driven member 11) (via a connecting member 8 described later), and the other side of the moving member 2 in the first direction D1 is connected to the drive target O (via the long member 7). In the present embodiment, the moving member 2 drives the drive target O by moving in one direction in the first direction D1 with respect to the base 3 by the driving force of the driving unit 4. Note that the expression "moves in the first direction D1" includes both the case where a part of the moving member 2 (the first moving member 21 in the present embodiment) moves relative to the other part of the moving member 2 (the second moving member 22 in the present embodiment) and thus moves in the first direction D1 with respect to the base 3, and the case where the entire moving member 2 moves in the first direction D1 with respect to the base 3.

[0022] The configuration of the moving member 2 described in this specification is merely an example. The shape and structure of the moving member 2 are configured to move in the first direction D1 with respect to the base 3, and are not particularly limited as long as the detection principle of the load sensor 1 described later can be applied. The moving member 2 may be constituted by one member or may be constituted by a plurality of members. In the present embodiment, the moving member 2 has a first moving member 21 and a second moving member 22 that are relatively movable in the first direction D1 with respect to each other. Although details will be described later, in the present embodiment, as shown in FIGS. 2 and 3, after the first moving member 21 has moved a predetermined amount (after the first moving member 21 has moved to the movement limit (see FIG. 3)), when a load of a predetermined amount or more is applied to the moving member 2, the second moving member 22 moves in the first direction D1 together with the driven member 11 against the biasing force of the biasing member 16 of the load sensor 1 (see FIG. 4).

[0023] The first moving member 21 is connected to the second moving member 22 so as to relatively move in the first direction D1 with respect to the second moving member 22. In the present embodiment, one side of the first moving member 21 in the first direction D1 is connected to the second moving member 22, and the other side of the first moving member 21 in the first direction D1 is connected to the connecting member 6.

[0024] In the present embodiment, as shown in FIG. 2, the first moving member 21 has a screw portion 211 and is screwed with the first screw portion 221 of the second moving member 22. By the second moving member 22 being rotationally driven about the axis X by the driving force of the driving unit 4, the first moving member 21 relatively moves in the first direction D1 with respect to the second moving member 22. In the present embodiment, the rotation of the first moving member 21 about the axis X is restricted, and by the second moving member 22 rotating, the first moving member 21 moves in the first direction D1 with respect to the second moving member 22.

[0025] The shape and structure of the first moving member 21 are not particularly limited as long as the second moving member 22 is rotationally driven about the axis X so that the first moving member 21 can move relative to the second moving member 22 in the first direction D1. In the present embodiment, the first moving member 21 is constituted by a shaft member extending in the first direction D1. The screw portion 211 of the first moving member 21 is constituted by a male screw provided on the outer periphery of the first moving member 21 in the present embodiment. However, for example, when the first screw portion of the second moving member 22 is constituted by a male screw provided on the outer periphery of the second moving member 22, the first moving member may be formed in a cylindrical shape, and the screw portion of the first moving member may be constituted by a female screw provided on the inner surface of the cylindrical first moving member.

[0026] The second moving member 22 rotates about the axis X to relatively move the first moving member 21 relative to the second moving member 22 in the first direction D1. In the present embodiment, the second moving member 22 is connected to the driving unit 4 (via the transmission unit 5) and rotates about the axis X by the driving force of the driving unit 4. In the present embodiment, the second moving member 22 is connected to the transmission unit 5 so that the second moving member 22 rotates about the axis X by the driving force of the driving unit 4 transmitted by the transmission unit 5. Specifically, the second moving member 22 has an engaged portion 223 (see FIG. 1) that engages with the transmission unit 5 (fitting member 51) about the axis X. In the present embodiment, the engaged portion 223 of the second moving member 22 is provided on the outer surface of the second moving member 22 and engages with an engaging portion (not shown) provided on the inner periphery of the fitting member 51, so that the second moving member 22 rotates about the axis X by the rotation of the fitting member 51.

[0027] In the present embodiment, one side of the second moving member 22 in the first direction D1 is connected to the load sensor 1, and the other side of the second moving member 22 in the first direction D1 is connected to the first moving member 21. The second moving member 22 has a first screw portion 221 that screws with the screw portion 211 of the first moving member 21 as shown in FIG. 2. As described above, when the second moving member 22 rotates about the axis X, the first moving member 21 moves relative to the second moving member 22 in the first direction D1.

[0028] The shape and structure of the second moving member 22 are not particularly limited as long as the first moving member 21 can be relatively moved in the first direction D1 with respect to the second moving member 22 by the rotation of the second moving member 22 around the axis X. In the present embodiment, the second moving member 22 is constituted by a cylindrical member extending in the first direction D1. The first screw portion 221 of the second moving member 22 is constituted by a female screw provided on the inner surface of the cylindrical second moving member 22 in the present embodiment. However, for example, when the screw portion of the first moving member is constituted by a female screw provided on the inner surface of the cylindrical first moving member, the second moving member is constituted by a shaft member, and the first screw portion of the second moving member which is the shaft member may be constituted by a male screw provided on the outer surface of the second moving member.

[0029] Also, in the present embodiment, as shown in FIG. 2, the second moving member 22 has a second screw portion 222 that engages with the screw portion 81 of the connecting member 8. The second screw portion 222 has screw grooves cut in the opposite direction to the first screw portion 221. Also, the screw groove of the screw portion 211 of the first moving member 21 and the screw portion 81 of the connecting member 8 are cut in the opposite direction. Thereby, as shown in FIGS. 2 and 3, when the second moving member 22 rotates around the axis X, the first moving member 21 relatively moves in one direction in the first direction D1 with respect to the second moving member 22, and the connecting member 8 relatively moves in the other direction in the first direction D1 with respect to the second moving member 22 (in the present embodiment, until a predetermined or more load is applied to the moving member 2, the connecting member 8 is suppressed from moving with respect to the base portion 3 by the biasing member 16 provided on the load sensor 1, so the second moving member 22 moves in one direction in the first direction D1 with respect to the connecting member 8). The second screw portion 222 of the second moving member 22 is constituted by a female screw provided on the inner surface of the cylindrical second moving member 22 in the present embodiment. However, for example, when the connecting member is formed in a cylindrical shape and the screw portion of the connecting member 8 is constituted by a female screw provided on the inner surface of the cylindrical connecting member, the second moving member is constituted by a shaft member, and the second screw portion of the second moving member which is the shaft member may be constituted by a male screw provided on the outer surface of the second moving member.

[0030] Note that the configuration of the moving member 2 is not limited to that shown in FIGS. 1 to 4. For example, as in the modified examples shown in FIGS. 5 and 6, the second moving member 22 and the connecting member 8 are not screwed together, and the second moving member 22 and the connecting member 8 (and the driven member 11) may be connected so that relative movement in the first direction D1 does not occur therebetween. In the modified examples shown in FIGS. 5 and 6, when the second moving member 22 rotates about the axis X by the driving force of the driving unit 4, the first moving member 21 moves in one direction in the first direction D1 with respect to the second moving member 22. After the first moving member 21 has moved a predetermined amount (after the first moving member 21 has moved to the limit of movement), when a load of a predetermined value or more is applied to the moving member 2, the second moving member 22 moves in the first direction D1 together with the driven member 11 against the biasing force of the biasing member 16 of the load sensor 1. Note that, as will be described later, the modified example shown in FIG. 5 has the same basic operating principle as the embodiment shown in FIGS. 1 to 4 except that the configuration of the load sensor 1 is different from that of the embodiment shown in FIGS. 1 to 4. Further, the modified example shown in FIG. 6 has the same basic operating principle as the embodiment shown in FIGS. 1 to 4 except that the configuration and position of the load sensor 1 are different from those of the embodiment shown in FIGS. 1 to 4.

[0031] The connecting member 8 connects the moving member 2 and the load sensor 1. Specifically, the connecting member 8 connects the moving member 2 and the load sensor 1 so that a load applied in the first direction D1 to the moving member 2 can be transmitted to the load sensor 1 (driven member 11). The shape and structure of the connecting member 8 are not particularly limited as long as the moving member 2 and the load sensor 1 can be connected so that a load applied in the first direction D1 to the moving member 2 can be transmitted to the load sensor 1 (driven member 11). As shown in FIGS. 2 to 4, the connecting member 8 has a connecting portion 82 that is connected to the driven member 11 so that a load in the first direction D1 applied to the moving member 2 (second moving member 22) is transmitted to the driven member 11. In the present embodiment, the connecting portion 82 is configured to engage with the driven member 11 in the first direction D1.

[0032] In this embodiment, as shown in FIGS. 2 to 4, FIGS. 7 and 8, the connecting member 8 is configured as a shaft member extending in the first direction D1 that is screwed into the second moving member 22. In this embodiment, the connecting member 8 has a threaded portion 81 that is screwed into the second threaded portion 222 of the second moving member 22. Note that, as in the modified examples shown in FIGS. 5 and 6, the connecting member 8 may not have a threaded portion. Also, in this embodiment, the connecting member 8 is provided separately from the second moving member 22 and the driven member 11, but it may be provided integrally with the second moving member 22 or the driven member 11.

[0033] Next, the load sensor 1 will be described. As shown in FIGS. 2 to 4, the load sensor 1 includes a driven member 11 that is connected to the moving member 2 and is movable along the first direction D1 as the moving member 2 moves in the first direction D1, a first sensor element 12 that moves together with the driven member 11, a mounting member 13 for attaching the first sensor element 12 to the driven member 11, a second sensor element 14 that is fixedly attached to the base 3 of the drive device DR and interacts with the first sensor element 12, and a guide portion 15 that guides the first sensor element 12 along a predetermined path so that the first sensor element 12 moves relative to the second sensor element 14 in a predetermined positional relationship. In this embodiment, the load sensor 1 further includes a biasing member 16 that biases the driven member 11 in the first direction D1.

[0034] <Operating Principle of Load Sensor> The load sensor 1, details of which will be described later, when a load equal to or greater than a predetermined value is applied to the moving member 2, the driven member 11 moves together with the moving member 2 in the first direction D1 by a predetermined amount or more, and the positional relationship between the first sensor element 12 and the second sensor element 14 changes. As a result, it is detected that a load equal to or greater than a predetermined value has been applied to the moving member 2. Therefore, it is detected that a load equal to or greater than a predetermined value has been applied to the drive target O. More specifically, when a load equal to or greater than a predetermined value is applied to the moving member 2, the driven member 11 moves in the first direction D1 by a predetermined amount against the biasing force of the biasing member 16, so that the first sensor element 12 that moves in the first direction D1 together with the driven member 11 and the second sensor element 14 that remains stationary with respect to the base 3 change in positional relationship. The change in the sensor output at this time detects that a load equal to or greater than a predetermined value has been applied to the moving member 2. Until a predetermined load is applied to the moving member 2, each component of the drive device DR is designed by the biasing member 16 or the like so that the driven member 11 does not move or the amount of movement is within a predetermined range. Therefore, when it is detected by the sensor outputs from the first sensor element 12 and the second sensor element 14 that the driven member 11 has moved by a predetermined amount or more, it is detected that a load equal to or greater than a predetermined value has been applied to the moving member 2 and the drive target O. Note that the "load equal to or greater than a predetermined value" applied to the moving member 2 and the "predetermined amount" of the movement amount of the driven member 11 are not particularly limited because they are appropriately changed according to the drive device DR and the drive target O to which the load sensor 1 is applied.

[0035] The driven member 11 is directly or indirectly connected to the moving member 2 and moves along the first direction D1 as the moving member 2 moves in the first direction D1. As described above, the first sensor element 12 is connected to the driven member 11 via the mounting member 13. Therefore, when the driven member 11 moves in the first direction D1, the first sensor element 12 also moves in the first direction D1, and the positional relationship between the first sensor element 12 and the second sensor element 14 changes.

[0036] In this embodiment, the driven member 11 is biased by a biasing member 16 so that the driven member 11 is suppressed from moving in the first direction D1 until a load equal to or greater than a predetermined value is applied to the moving member 2 to which the driven member 11 is connected. More specifically, when the object O to be driven is operated by the moving member 2, the driven member 11 receives a force from the second moving member 22 (via the connecting member 8) in one direction of the first direction D1 (in this embodiment, the other direction of the first direction D1 (the left direction in FIG. 2)). On the other hand, the driven member 11 is biased by the biasing member 16 in the direction opposite to the force applied from the second moving member 22 to the driven member 11 (the right direction in FIG. 2). Therefore, the driven member 11 is suppressed from relatively moving with respect to the base 3 until a load equal to or greater than a predetermined value is applied to the second moving member 22 (until the load applied to the second moving member 22 exceeds the biasing force of the biasing member 16), and is held at a predetermined position shown in FIG. 2. When a load equal to or greater than a predetermined value exceeding the biasing force of the biasing member 16 is applied to the second moving member 22 in the direction opposite to the biasing direction of the biasing member 16 (the left direction in FIG. 2), the driven member 11 moves in the direction opposite to the biasing direction of the biasing member 16 (the left direction in FIG. 2) of the first direction D1 together with the second moving member 22.

[0037] The position where the driven member 11 is provided is not particularly limited as long as the driven member 11 can move in the first direction D1 together with the moving member 2 and the first sensor element 12. In this embodiment, the driven member 11 is provided on one side of the moving member 2 (the second moving member 22) in the first direction D1. However, as shown in the modification example of FIG. 6, it may be provided on the other side of the moving member 2 (the second moving member 22) in the first direction D1.

[0038] In this embodiment, as shown in FIGS. 1 and 2, the driven member 11 is movably provided in the first direction D1 in the sensor housing portion 31 of the base portion 3. In this embodiment, the driven member 11 is provided so as to move in the first direction D1 between the contact wall W1 provided on the base portion 3 and the stop wall W2. The contact wall W1 contacts the driven member 11 biased in the first direction D1 by the biasing member 16, and holds the driven member 11 at a predetermined position. In this embodiment, as shown in FIG. 2, the contact wall W1 is constituted by the inner surface of one end wall of the base portion 3 in the first direction D1. However, the position where the contact wall is provided is not particularly limited as long as it is provided so as to hold the driven member 11 biased by the biasing member 16 at a predetermined position in the first direction D1. The stop wall W2 limits the amount of movement of the driven member 11 within a predetermined range by contacting and stopping the driven member 11 when a load equal to or greater than a predetermined value is applied to the moving member 2 and the driven member 11 moves in the first direction D1. Thereby, the large deformation of the biasing member 16 is suppressed, and the breakage of the biasing member 16 and the constituent members of the drive device DR is suppressed. The shape and structure of the stop wall W2 are not particularly limited as long as the amount of movement of the driven member 11 can be limited within a predetermined range by contacting and stopping the driven member 11. In this embodiment, the stop wall W2 is provided at one end of a columnar support portion 35 (see FIGS. 9 and 10) that extends substantially perpendicularly from the bottom surface 3a (see FIG. 2) of the base portion 3 and extends in the first direction D1 and the third direction D3.

[0039] The shape and structure of the driven member 11 are not particularly limited as long as the driven member 11 can move in the first direction D1 together with the moving member 2 and the first sensor element 12. In the present embodiment, as shown in FIGS. 7, 8, and 10, the driven member 11 is a cylindrical body extending coaxially with the moving member 2. Specifically, as shown in FIGS. 2, 7, and 8, the driven member 11 includes a bottom wall 111 extending perpendicular to the first direction D1 and a side wall 112 extending in a direction perpendicular to the bottom wall 111 (the first direction D1), and is constituted by a bottomed cylindrical body. A connecting member 8 is connected to the bottom wall 111. Specifically, as shown in FIGS. 2, 7, and 8, one end of the connecting member 8 in the first direction D1 penetrates the bottom wall 111, and a connecting portion 82 provided on a head portion having an enlarged diameter at the end of the connecting member 8 engages with the outer surface of the bottom wall 111 in the first direction D1. In the present embodiment, the connecting member 8 is attached to the driven member 11 so that the relative rotation of the connecting member 8 about the axis X with respect to the driven member 11 is restricted, so that the rotation of the connecting member 8 about the axis X is restricted. The driven member 11 is also provided on the base 3 so that the relative rotation of the driven member 11 about the axis X with respect to the base 3 is restricted. Therefore, when the second moving member 22 rotates about the axis X, the co-rotation of the connecting member 8 about the axis X is suppressed.

[0040] Further, as shown in FIG. 2, a biasing member 16 is accommodated in the internal space of the driven member 11 defined by the inner surfaces of the bottom wall 111 and the side wall 112. The inner surface of the bottom wall 111 functions as a spring seat against which one end of the biasing member 16, which is a coil spring, abuts in the first direction D1. The other end of the biasing member 16 in the first direction D1 abuts against a spring seat provided on the base 3. In the present embodiment, the spring seat of the base 3 is provided on the stop wall W2. On one side (the upper side in FIG. 2) of the outer surface of the side wall 112 in the second direction D2, a mounted portion 112a to which the mounting member 13 is mounted is provided. The shape and structure of the mounted portion 112a are not particularly limited as long as the mounting member 13 can be mounted.

[0041] The biasing member 16 biases the driven member 11 in the first direction D1. Specifically, the biasing member 16 biases the driven member 11 in the first direction D1 such that the driven member 11 does not move or the amount of movement is within a predetermined range until a predetermined load is applied to the moving member 2. The shape and structure of the biasing member 16 are not particularly limited as long as the driven member 11 can be biased in the first direction D1. In the present embodiment, the biasing member 16 is a coil spring extending in the first direction D1, but the biasing member 16 may be other biasing members such as an air spring or rubber. In the present embodiment, the biasing member 16 is provided such that the driven member 11 presses the contact wall W1 in the first direction D1 in a state where the moving member 2 is unloaded, such as when the driving device DR is not driven. Specifically, the biasing member 16, which is a coil spring, is provided in a compressed state, and the driven member 11 is configured to be held at a predetermined position by the biasing force of the biasing member 16 until a load equal to or greater than a predetermined value is applied to the moving member 2.

[0042] The first sensor element 12 and the second sensor element 14 interact to detect a change in the positional relationship between the first sensor element 12 and the second sensor element 14, and detect that a load equal to or greater than a predetermined value has been applied to the moving member 2. Specifically, when a load equal to or greater than a predetermined value is applied to the moving member 2, the first sensor element 12 moves in the first direction D1 together with the driven member 11 (see FIG. 4). As a result, the positional relationship between the first sensor element 12 and the second sensor element 14 when a load equal to or greater than a predetermined value is applied to the moving member 2, as shown in FIG. 4, changes with respect to the positional relationship between the first sensor element 12 and the second sensor element 14 before a load equal to or greater than a predetermined value is applied to the moving member 2, as shown in FIGS. 2 and 3. Based on the sensor output corresponding to the change in the positional relationship between the first sensor element 12 and the second sensor element 14, the load sensor 1 detects that a load equal to or greater than a predetermined value has been applied to the moving member 2.

[0043] The configurations of the first sensor element 12 and the second sensor element 14 are not particularly limited as long as they can detect a change in the positional relationship between the first sensor element 12 and the second sensor element 14 by interacting with each other and detect that a load equal to or greater than a predetermined value has been applied to the moving member 2. In the present embodiment, the first sensor element 12 and the second sensor element 14 constitute a magnetic field sensor that detects a change in the magnetic field due to a change in the positional relationship between a magnet and a Hall IC. The first sensor element and the second sensor element may be other sensors, such as an optical sensor constituted by a light emitting unit and a light receiving unit, instead of the magnetic field sensor. In the present embodiment, the first sensor element 12 is a magnet and the second sensor element 14 is a Hall IC. When the first sensor element 12 that moves in the first direction D1 together with the driven member 11 is a magnet and the second sensor element 14 is a Hall IC, wiring is provided on the side of the second sensor element 14 that is fixedly attached to the base 3, and no wiring is required for the moving first sensor element 12. Therefore, it is not necessary to consider wiring when arranging the first sensor element 12, and the degree of freedom in the design of the load sensor 1 can be increased.

[0044] In this embodiment, as shown in FIGS. 2, 7, and 8, the first sensor element 12 is connected to the driven member 11 via the mounting member 13. Thereby, the first sensor element 12 moves together with the driven member 11 while maintaining a predetermined positional relationship with the driven member 11. As shown in FIGS. 7 and 8, the first sensor element 12 includes a magnet 121 and a magnet housing 122. The magnet housing 122 is a container configured to be able to attach the magnet 121. The magnet housing 122 has a magnet housing portion 122a and a connection portion 122b to which one end of the mounting member 13 is connected. As will be described later, the magnet housing 122 is guided inside the guide portion 15 and has a shape corresponding to the internal cavity of the guide portion 15. The shape of the magnet housing 122 is not particularly limited as long as it can enter the internal cavity of the guide portion 15. In this embodiment, it is formed in a substantially rectangular parallelepiped shape. In this embodiment, as shown in FIGS. 8 and 11, the magnet housing 122 has protrusions P protruding in the second direction D2 from the surfaces provided at both ends of the magnet housing 122 in the second direction D2. The protrusions P reduce the sliding resistance between the magnet housing 122 and the guide portion 15 by reducing the contact area with the guide portion 15. In this embodiment, the protrusions P are formed in a rail shape extending in the first direction D1.

[0045] The second sensor element 14 is fixedly attached to the base 3. In this embodiment, as shown in FIGS. 2, 9, and 10, the second sensor element 14 is supported by the substrate S and attached to the base 3 via the substrate S. More specifically, the substrate S to which the second sensor element 14 is attached is fixed to the guide member G provided with the guide portion 15, and the guide member G is fixed to the base 3 (the support portion 35), so that the second sensor element 14 is fixed to the base 3. By fixedly attaching (fixing) the second sensor element 14 to the base 3, the second sensor element 14 does not move relative to the base 3 in the first direction D1, the second direction D2, and the third direction D3.

[0046] The mounting member 13 attaches the first sensor element 12 to the driven member 11. When the first sensor element 12 is attached to the driven member 11 by the mounting member 13, as shown in FIGS. 3 and 4, when the driven member 11 moves in the first direction D1, the first sensor element 12 moves in the first direction D1 together with the driven member 11. In the present embodiment, as shown in FIGS. 7, 8, and 10, the mounting member 13 has a displacement portion 131 that can be displaced in a direction perpendicular to the first direction D1. As will be described later, when the position of the first sensor element 12 is corrected so as to move along a predetermined path of the guide portion 15, the displacement portion 131 displaces in response to a change in the positional relationship between the driven member 11 and the first sensor element 12 (see FIG. 14).

[0047] The shape and structure of the mounting member 13 are not particularly limited as long as the first sensor element 12 can be attached to the driven member 11 and it has the displacement portion 131. In the present embodiment, as shown in FIGS. 7, 8, and 10, the mounting member 13 is constituted by an elongated plate-like member that is cantilever-supported by the driven member 11 and extends in the first direction D1. The mounting member 13 constituted by the plate-like member has a predetermined rigidity and a predetermined flexibility. Note that the mounting member 13 may be a linear member such as a wire or a rod that has a predetermined rigidity and a predetermined flexibility. The mounting member 13 includes a mounting portion 132 that is provided on one end side of the mounting member 13 and attached to the outer periphery of the driven member 11, and a first sensor support portion 133 (see FIG. 2) that is provided on the other end side of the mounting member 13 and supports the first sensor element. A displacement portion 131 is provided between the mounting portion 132 and the first sensor support portion 133 in the first direction D1. Details of the displacement portion 131 will be described later.

[0048] As shown in FIGS. 7 and 8, the attachment portion 132 is fixed to the outer periphery of the driven member 11 by a predetermined fixing means. In the present embodiment, the attachment portion 132 is formed in a plate shape extending in the first direction D1 and is fixed to the outer periphery of the driven member 11 by screws. The first sensor support portion 133 is provided at an end of the attachment member 13 opposite to the end where the attachment portion 132 is provided, and supports the first sensor element 12 in a cantilevered manner. The fixing method between the first sensor support portion 133 and the first sensor element 12 is not particularly limited, but in the present embodiment, the first sensor support portion 133 is fixed in a state of being inserted into the magnet housing 122 of the first sensor element 12.

[0049] The guide portion 15 guides the first sensor element 12 along a predetermined path so that the first sensor element 12 moves relative to the second sensor element 14 in a predetermined positional relationship. Here, the "predetermined path" refers to the movement path of the first sensor element 12 such that the first sensor element 12 and the second sensor element 14 can accurately detect that a load of a predetermined value or more has been applied to the moving member 2. Specifically, the predetermined path of the guide portion 15 is a path that extends substantially linearly along the first direction D1, and the distance between the first sensor element 12 and the second sensor element 14 in at least the second direction D2 is substantially equal to a predetermined value (for example, the designed distance). In the present embodiment, the predetermined path of the guide portion 15 is configured such that the distance between the first sensor element 12 and the second sensor element 14 in the second direction D2 is substantially equal to the predetermined value, and the center of the first sensor element 12 in the third direction D3 coincides substantially with the center of the second sensor element 14 in the third direction D3 (for example, the deviation between the center of the first sensor element 12 in the third direction D3 and the center of the second sensor element 14 is 5% or less of the length of the first sensor element 12 in the third direction D3).

[0050] In the present embodiment, as shown in FIGS. 9 and 11, the case portion 15 has a first guide surface 151 that faces the first surface 12a of the first sensor element 12, which is close to the axis X (see FIG. 9) of the moving member 2 in the second direction D2, and a second guide surface 152 that faces the second surface 12b of the first sensor element 12, which is far from the axis X of the moving member 2 in the second direction D2. Further, in the present embodiment, the case portion 15 has a third guide surface 153 and a fourth guide surface 154 that extend so as to connect the first guide surface 151 and the second guide surface 152. The third guide surface 153 and the fourth guide surface 154 face a third surface 12c and a fourth surface 12d that are perpendicular to the first surface 12a and the second surface 12b of the first sensor element 12, respectively. In the present embodiment, a predetermined path of the case portion 15 is defined by the first guide surface 151, the second guide surface 152, the third guide surface 153, and the fourth guide surface 154.

[0051] In the present embodiment, as shown in FIGS. 9 to 11, the case portion 15 is provided on a case member G that is attached to the base portion 3. The case member G has a fixing portion G1 that is fixed to a pair of support portions 35 that are separated from each other in the third direction D3 with the connecting member 8 interposed therebetween in the third direction D3, and a substrate connection portion G2 to which the substrate S is fixed. In the present embodiment, the case portion 15 is attached to the base portion 3 via a case member G that is separate from the base portion 3, but the case portion may be provided integrally with the base portion 3.

[0052] As described above, the second sensor element 14 is fixedly attached to the base 3, and the first sensor element 12 is guided by the guide portion 15 along a predetermined path. Therefore, for example, even when there is play between the components constituting the drive device DR or misalignment of the mounting positions of the components, the first sensor element 12 is guided by the guide portion G, so that the first sensor element 12 is corrected to an appropriate position (distance) with respect to the second sensor element 14. Therefore, a decrease in the detection accuracy of the load sensor 1 is suppressed, and false detection by the load sensor 1 is suppressed. More specifically, when there is play between the components constituting the drive device DR or misalignment of the mounting positions of the components, as shown in FIG. 12, a positional deviation in the second direction D2 between the first sensor element 12 and the second sensor element 14, or as shown in FIG. 13, a positional deviation in the third direction D3 between the first sensor element 12 and the second sensor element 14 may occur. In this case, the sensor output may change due to a change in the distance or positional deviation between the first sensor element 12 and the second sensor element 14. Therefore, the detection accuracy of the load sensor 1 may decrease, or a false detection may occur in which it is determined that a load of a predetermined amount or more is not applied to the load sensor 1 although a load of a predetermined amount or more is applied, or it is determined that a load of a predetermined amount or more is applied to the load sensor 1 although a load of a predetermined amount or more is not applied. In the present embodiment, the guide portion 15 is configured to suppress the positional deviation of the first sensor element 12 in the second direction D2 and the third direction D3 with respect to the second sensor element 14. Therefore, even when a positional deviation as shown in FIGS. 12 and 13 may occur due to play between the components constituting the drive device DR or misalignment of the mounting positions of the components, from the state shown by the dashed-dotted line in FIG. 14 to the state shown by the solid line, the position of the first sensor element 12 is corrected by the guide portion 15, and it is possible to accurately detect that a load of a predetermined amount or more is applied to the moving member 2.

[0053] Also, in the present embodiment, as described above, the attachment member 13 has a displacement portion 131 that is displaceable in a direction perpendicular to the first direction D1. As shown in FIG. 14, the displacement portion 131 allows a change in the positional relationship between the first sensor element 12 and the driven member 11 when the position of the first sensor element 12 is corrected by the above-described guide portion 15. Specifically, as shown in FIG. 14, when the guide portion 15 is not provided, if play occurs between the components of the drive device DR or the mounting positions of the components are misaligned, the first sensor element 12 will be displaced from the ideal position suitable for accurate detection (see the two-dot chain lines in FIGS. 12 to 14). In the present embodiment, as described above, the position of the first sensor element 12 is corrected by the guide portion 15 from the position indicated by the two-dot chain line to the position indicated by the solid line in FIG. 14. At this time, the positional relationship between the first sensor element 12 and the driven member 11 changes before and after being guided by the guide portion 15 (see FIG. 14). In the present embodiment, since the displacement portion 131 is provided on the attachment member 13, even if the positional relationship between the first sensor element 12 and the driven member 11 changes in a direction perpendicular to the first direction D1, the displacement portion 131 displaces in that direction, allowing the change in the positional relationship between the first sensor element 12 and the driven member 11. Therefore, even if there is a change in the positional relationship between the first sensor element 12 and the driven member 11 when the first sensor element 12 is guided by the guide portion 15, unreasonable forces are prevented from being applied to the components of the load sensor 1, such as the first sensor element 12, the attachment member 13, and the driven member 11. Thus, damage to the components of the load sensor 1 is suppressed.

[0054] Incidentally, the "direction perpendicular to the first direction D1", which is the direction in which the displacement portion 131 is displaced, is preferably the second direction D2, but may be the third direction D3 or a direction between the second direction D2 and the third direction D3. Further, the displacement portion 131 may be displaceable mainly in the second direction D2 while also being displaceable in the third direction D3 or other directions. In the present embodiment, the displacement portion 131 is configured to be able to displace the first sensor element 12 in the second direction D2. Since the positional deviation between the first sensor element 12 and the second sensor element 14 in the second direction easily affects the sensor performance, by making the displacement portion 131 displaceable in the second direction D2, it is possible to effectively suppress the reduction of the sensor performance. Incidentally, the displacement portion 131 of the present embodiment is also configured to be slightly displaceable in the third direction D3.

[0055] Incidentally, the length L1 (see FIG. 7) of the displacement portion 131 in the first direction D1 is not particularly limited as long as it can allow a change in the positional relationship between the first sensor element 12 and the driven member 11. For example, the length L1 of the displacement portion 131 in the first direction D1 can be 0.5 to 2 times, preferably 0.8 to 1.5 times, the length L2 of the first sensor element 12 in the first direction D1.

[0056] In the present embodiment, as shown in FIGS. 7 and 8, the displacement portion 131 is a leaf spring that can swing the first sensor element 12 in the second direction D2. Thereby, when the position of the first sensor element 12 in the second direction D2 is corrected, the displacement portion 131 elastically deforms and swings in the second direction D2. By the elastic deformation of the displacement portion 131 provided as a leaf spring, when the positional relationship between the first sensor element 12 and the driven member 11 changes, unreasonable forces between the constituent members of the load sensor 1 are more likely to be reduced, and damage to the constituent members of the load sensor 1 can be more suppressed. Incidentally, as long as the displacement portion 131 is configured to be elastically deformable, it may be constituted by a wire, a rod, or the like that functions elastically.

[0057] Further, in the present embodiment, as shown in FIG. 8, the displacement portion 131 has a width-reduced portion 131a where a part of the width of the displacement portion 131 is narrower than the other parts. In this case, the displacement portion 131 is more likely to elastically deform at the width-reduced portion 131a. Therefore, it can easily follow the change in the positional relationship between the first sensor element 12 and the driven member 11. In the present embodiment, the displacement portion 131 has the width-reduced portion 131a and a width-expanded portion 131b that is wider than the width-reduced portion 131a. In this case, the rigidity of the displacement portion 131 is high at the width-expanded portion 131b, and it is suppressed that the displacement portion 131 bends too much as a whole. Therefore, when the first sensor element 12 and the driven member 11 move in the first direction D1 in conjunction with each other, it is suppressed that the entire displacement portion 131 bends too much and the distance between the first sensor element 12 and the driven member 11 in the first direction D1 changes. Therefore, when the displacement portion 131 has the width-reduced portion 131a and the width-expanded portion 131b, while easily following the change in the positional relationship between the first sensor element 12 and the driven member 11, false detection due to the change in the distance between the first sensor element 12 and the driven member 11 in the first direction D1 is suppressed.

[0058] Further, in the present embodiment, as shown in FIG. 2, the displacement portion 131 is inclined and extends so as to approach the axis X of the moving member 2 as it goes from the mounting portion 132 toward the first sensor support portion 133. In this case, compared with the case where the displacement portion 131 extends parallel to the axis X of the moving member 2 from the mounting portion 132, the first sensor element 12 supported by the first sensor support portion 133 can be arranged at a position closer to the axis X of the moving member 2. Therefore, the first sensor element 12 and the second sensor element 14 can be arranged at positions closer to the moving member 2 in the second direction D2, and the base portion 3 can be miniaturized in the second direction D2.

[0059] Next, the load sensor of the second embodiment will be described with reference to FIGS. 15 and 16. In the following description, the description of matters common to the above-described first embodiment will be omitted, and the description will focus on the differences. Note that all of the matters described in the first embodiment can be applied to the load sensor of the second embodiment as long as the object of the invention can be achieved, and the configuration of the present embodiment and the content described in the first embodiment can be used in combination. Further, the effects obtained by the configuration described in the first embodiment can also be obtained in the second embodiment as long as the configuration is provided.

[0060] In the present embodiment, as shown in FIGS. 15 and 16, the displacement portion 131 includes a first displacement portion 1311 configured to displace the first sensor element 12 in the second direction D2, and a second displacement portion 1312 configured to displace the first sensor element 12 in the third direction D3. The first displacement portion 1311 is a portion that mainly displaces in the second direction D2 and can be easily displaced in the direction indicated by the arrow A1 in FIG. 15. The second displacement portion 1312 is a portion that mainly displaces in the third direction D3 and can be easily displaced in the direction indicated by the arrow A2 in FIG. 16. In the present embodiment, the first displacement portion 1311 is a leaf spring that can swing the first sensor element 12 in the second direction D2, and the second displacement portion 1312 is a leaf spring that can swing the first sensor element 12 in the third direction D3. In the present embodiment, as described above, the displacement portion 131 has both a first displacement portion 1311 that is a portion that mainly displaces in the second direction D2 and a second displacement portion 1312 that is a portion that mainly displaces in the third direction D3. In this case, for example, even when the positional relationship between the first sensor element 12 and the driven member 11 changes in both the second direction D2 and the third direction D3 due to play between the constituent members constituting the drive device DR or misalignment of the mounting positions of the constituent members, the displacement portion 131 can be easily displaced in the second direction D2 and the third direction D3.

[0061] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The above-described embodiments mainly describe the invention having the following configuration.

[0062] (1) In a driving device including a moving member that moves in a first direction with respect to a base, a load sensor that detects that a load equal to or greater than a predetermined value has been applied to the moving member, the load sensor including: a driven member connected to the moving member and movable along the first direction as the moving member moves in the first direction; a first sensor element that moves with the driven member; a mounting member for attaching the first sensor element to the driven member; a second sensor element fixedly attached to the base of the driving device and interacting with the first sensor element; a guide portion that guides the first sensor element along a predetermined path so that the first sensor element moves in a predetermined positional relationship with respect to the second sensor element; and the mounting member has a displacement portion displaceable in a direction perpendicular to the first direction. The load sensor.

[0063] (2) The displacement portion is configured to displace the first sensor element in a second direction, which is a direction in which the first sensor element and the second sensor element face each other, and / or in a third direction perpendicular to the first direction and the second direction. The load sensor according to (1).

[0064] (3) The displacement portion is a leaf spring that can swing the first sensor element in the second direction. The load sensor according to (1) or (2).

[0065] (4) The displacement portion has a narrow-width portion where a part of the width of the displacement portion is narrower than other parts. The load sensor according to any one of (1) to (3).

[0066] (5) The displacement portion includes: a first displacement portion configured to displace the first sensor element in a second direction, which is a direction in which the first sensor element and the second sensor element face each other; The first sensor element is configured to be displaceable in a third direction perpendicular to the first direction and the second direction by a second displacement portion The load sensor according to any one of (1) to (4), which has the above structure.

[0067] (6) The first displacement portion is a leaf spring that allows the first sensor element to swing in the second direction. The second displacement portion is a leaf spring that allows the first sensor element to swing in the third direction. The load sensor according to any one of (1) to (5), which has the above structure.

[0068] (7) The driven member is a cylindrical body that extends coaxially with the moving member. The mounting member is constituted by an elongated plate-like member that is cantilever-supported by the driven member and extends in the first direction. The mounting member A mounting portion provided on one end side of the mounting member and attached to the outer periphery of the driven member, and A first sensor support portion provided on the other end side of the mounting member and supporting the first sensor element are provided. The displacement portion is constituted by a leaf spring that extends between the mounting portion and the first sensor support portion. The displacement portion extends inclined so as to approach the axis of the moving member from the mounting portion toward the first sensor support portion. The load sensor according to any one of (1) to (6), which has the above structure.

[0069] (8) The load sensor according to any one of (1) to (7), wherein the first sensor element is a magnet.

Explanation of Reference Numerals

[0070] 1 Load sensor 11 Driven member 111 Bottom wall 112 Side wall 112a Mounting portion 12 First sensor element 12a First surface 12b Second surface Side 3 of 12c Side 4 of 12d Magnet 121 Magnet housing 122 Magnet housing part 122a Connection part 122b Mounting member 13 Displacement part 131 Narrow part 131a Wide part 131b First displacement part 1311 Second displacement part 1312 Mounting part 132 First sensor support part 133 Second sensor element 14 Guide 15 First guide surface 151 Second guide surface 152 Third guide surface 153 Fourth guide surface 154 Biasing member 16 Moving member 2 First moving member 21 Thread part 211 Second moving member 22 First thread part 221 Second thread part 222 Engaged part 223 Base 3 Bottom surface of base 3a Sensor housing part 31 Drive part housing part 32 Moving path 33 Lead-out part 34 Support column part 35 Drive part 4 Motor 41 Transmission part 5 Fitting member 51 Connection member 6 Long member 7 Link member 8 Thread part 81 Link part 82 Bearing B First direction D1 Second direction D2 Third direction D3 DR drive device Internal member of Plan G Fixing part G1 Board connection part G2 Length of the displacement part in the first direction L1 Length of the first sensor element in the first direction L2 Object to be driven O Protrusion P Board S Contact wall W1 Stop wall W2 Axis of the moving member X

Claims

1. In a drive device including a moving member that moves in a first direction with respect to a base, a load sensor that detects that a load of a predetermined value or more has been applied to the moving member, wherein the load sensor includes a driven member connected to the moving member and movable along the first direction as the moving member moves in the first direction, a first sensor element that moves together with the driven member, a mounting member for mounting the first sensor element to the driven member, a second sensor element fixedly attached to the base of the drive device and interacting with the first sensor element, a guiding portion that guides the first sensor element along a predetermined path so that the first sensor element moves in a predetermined positional relationship with respect to the second sensor element and the mounting member has a displacement portion displaceable in a direction perpendicular to the first direction, the load sensor.

2. The displacement portion is configured to displace the first sensor element in a second direction which is a direction in which the first sensor element and the second sensor element face each other, and / or in a third direction perpendicular to the first direction and the second direction, the load sensor according to claim 1.

3. The displacement portion is a leaf spring that can swing the first sensor element in the second direction, the load sensor according to claim 2.

4. The displacement portion has a width-reduced portion where a width of a part of the displacement portion is narrower than that of other parts, the load sensor according to claim 3.

5. The displacement portion includes a first displacement portion configured to displace the first sensor element in a second direction which is a direction in which the first sensor element and the second sensor element face each other, and a second displacement portion configured to displace the first sensor element in a third direction perpendicular to the first direction and the second direction the load sensor according to claim 1.

6. The first displacement portion is a leaf spring that can swing the first sensor element in the second direction, the second displacement portion is a leaf spring that can swing the first sensor element in the third direction, the load sensor according to claim 5.

7. The driven member is a cylindrical body extending coaxially with the moving member, the mounting member is constituted by an elongated plate-like member extending in the first direction and cantilever-supported by the driven member, the mounting member has a mounting portion provided on one end side of the mounting member and attached to the outer periphery of the driven member, A first sensor support portion provided on the other end side of the mounting member and supporting the first sensor element, and comprising the displacement portion is constituted by a leaf spring extending between the mounting portion and the first sensor support portion, the displacement portion inclines and extends so as to approach the axis of the moving member as it goes from the mounting portion toward the first sensor support portion. The load sensor according to claim 1.

8. The load sensor according to claim 1, wherein the first sensor element is a magnet.

Images