LINEAR DRIVE DEVICE, MOTOR, AND LINEAR DRIVE DEVICE - MANUFACTURING METHOD

Abstract

Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating about an axis integral with an output shaft (7) of the motor; a nut mechanism (30) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut mechanism (30); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein the nut mechanism (30) includes a first nut portion (31) that is not relatively movable in an axial direction of the lead screw (2) with respect to the movable element (6), a second nut portion (32) that is relatively movable in the axial direction with respect to the movable element (6) toward the first plate portion (41) side of the first nut portion (31), and a first spring (35) that biases the second nut portion (32) in the axial direction, wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) is characterized in that it further comprises: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a).

Description

[Technical field]

[0001] The present invention relates to a linear drive device that linearly moves a movable member according to the rotation of a lead screw, a motor, and a linear drive device manufacturing method. [State of the art]

[0002] As a linear drive device that converts a rotary motion of a motor into a linear motion and reciprocates a movable member in a linear direction, a linear drive device disclosed in Patent Literature 1 by the present inventors or the like is known.

[0003] As in Fig. 23 and Fig. 24, the linear drive device disclosed in Patent Literature 1 includes a motor 20, a lead screw 22 rotatably assembled integrally with an output shaft 21 of the motor 20, a slider 24 in which a nut 23 meshing with the lead screw 22 is non-rotatably assembled, a guide shaft 25 arranged parallel to and at a distance from the lead screw 22 and inserted through a hole 24a is formed in the slider 24, and a bracket 26 fixed to a housing 39 of the motor 20. Fig. 23 is an illustrative view of a linear drive device in a prior art example. Fig. 24 is an illustrative view of a movable member used for a linear drive device shown in Fig. 23, and is a cross-sectional view taken along a line CC in Fig. 23 was recorded.

[0004] The bracket 26 includes a first plate portion 261 (one end portion) fixed to the housing 39 of the motor 20, a second plate portion 262 opposite to the first plate portion 261 on the distal end side of the lead screw 22, and a third plate portion 263 connecting the first plate portion 261 to the second plate portion 262 (the other end portion), and a plate surface of the third plate portion 263 extends parallel to the lead screw 22. A distal end portion of the lead screw 22 is rotatably supported by the brackets 26a provided in the second plate portion 262, and both end portions of the guide shaft 25 arranged in an oblique direction upward to the lead screw 22 are supported by both end portions of the bracket 26.

[0005] In the linear drive device, the slider 24 supporting the nut 23 meshed with the lead screw 22 is linearly reciprocated in the direction of the axis L by rotating the lead screw 22 with the motor 20. In such a linear drive device, there is a problem that chattering occurs in the circumferential direction in the slider 24 and an error in an operation may occur when starting, stopping or reversing the motor 20 due to clearance between the threaded rods of the lead screw 22 and the nut 23 or clearance between the hole portion 24a of the slider 24 and the guide shaft 25.Thereby, in the linear drive device disclosed in Patent Literature 1, the slider 24 is divided into two into a slider main body 27 and a movable portion 28 in the circumferential direction of the lead screw 22, and a spring 29 that biases both the slider main body 27 and the movable portion 28 in a direction opposite to a circumferential direction indicated by an arrow S in FIG. 24 is provided between the slider main body 27 and the movable portion 28, as shown in FIG. Fig. 23. Steel balls 90, which roll on the bracket 26, are provided at distal ends of the leg portions 27a and 28a extending from the slider main body 27 and the movable portion 28 to the bracket 26, respectively. Thereby, by pressing the leg portions 27a and 28a of the slider main body 27 and the movable portion 28 against the bracket 26 By means of a preload force of the spring 29, it is possible to prevent rattling in the circumferential direction from occurring in the slider 24 at the time of starting, stopping or reversing the engine 20.

[0006] Here, in the linear drive device, shown in Fig. 23, a nut mechanism in which a spring 230 is interposed between the two nuts 23 is used. In the nut mechanism, the nut 23a is provided on the side opposite to the motor 20, and the first plate portion 261 is supported by the slider 24 between the two nuts 23 so as to be relatively movable in the direction of the axis L with respect to the slider 24, and the nut 23b provided on the motor 20 side and the first plate portion 261 side is supported by the slider 24 so as not to be relatively movable in the direction of the axis L with respect to the slider 24. The spring 230 biases the nut 23a on the side opposite to the motor 20 and the first plate portion 261. Therefore, it is possible to suppress rattling from the nut 23 with respect to the lead screw 22. [Citation list][Patent literature]

[0007] [Patent Literature 1] Japanese Unexamined Patent Application Publication No. JP 2016-57470 A.

[0008] CN 1 457 409 A discloses a feed screw drive for moving a power transmission element engaged with a feed screw in the axial direction of the feed screw by rotationally driving the feed screw through a drive source, and an information recording and / or reproducing apparatus for recording and / or reproducing an information signal on / from a disc recording medium by driving a pickup through the feed screw drive. The feed screw drive for moving the power transmission element engaged with the feed screw in the axial direction of the feed screw by rotationally driving the feed screw through the drive source is provided with an elastic member for biasing the power transmission element in the axial direction of the feed screw.

[0009] CN 1 02 313 962 A discloses a focusing mechanism with a lead screw and gap elimination. The focusing mechanism comprises a lead screw, a fixing nut, an adjusting nut, a spring, guide shafts, a guide shaft base, and support plates. The fixing nut, the adjusting nut, and the spring form a gap elimination nut that is connected to an optical assembly. Two guide shafts are arranged symmetrically on two sides of the optical assembly and are connected to the optical assembly by the guide shaft base. Two ends of the guide shafts and the lead screw are respectively fixed to the two support plates, which are arranged in front of and behind the guide shafts and the lead screw, respectively.

[0010] DE 20 2007 017 535 U1 discloses an electromotive furniture double drive, which is provided with at least one drive motor that is drive-coupled to a speed reduction gear. In which an output element secured against rotation is movable in its longitudinal direction by means of the speed reduction gear. In which at least the speed reduction gear and the output element are arranged in a housing, and in which the end positions of each output element are limited by at least one limit switch. The output element or the housing has an adjustment device by means of which the position of the switching threshold of the at least one limit switch can be adjusted from outside the housing. [Summary of the invention][Technical problem]

[0011] In the linear drive device shown in Fig. 23 and Fig. 24, a driven member (not shown) is mounted and linearly moved relative to the slider 24. However, the linear drive device described in Patent Literature 1 has a structure in which the nut 23b is provided on the motor 20 side and the first plate portion 261-side is supported by the slider 24 so as not to be relatively movable relative to the slider 24 when rattling of the nuts 23 relative to the lead screw 22 is suppressed using the two nuts 23.As a result, there is a problem that a movable range of the slider 24 is narrowed because it is easy for the driven member to interfere with the motor 20, the first plate portion 261, and the members arranged around the motor 20 and the first plate portion 261 when the driven member is mounted at a position biased toward the side where the motor 20 and the first plate portion 261 are located with respect to the slider 24 and the slider 24 is driven in a direction approaching the motor 20 and the first plate portion 261.

[0012] Furthermore, in the linear drive device shown in Fig. 23 and Fig. 24, since the slider 24 is divided into the slider main body 27 and the movable portion 28, the spring 29 is interposed therebetween, and the steel balls 90 for rolling are provided at the distal ends of the two leg portions 27a and 28a, there is a problem that a structure is complicated and the number of components is increased, resulting in a high manufacturing cost. Furthermore, there is a problem that it is necessary to increase a bending strength of the bracket 26, increase a thickness of the bracket 26, and improve the flatness of the plate surface, because constant pressure is constantly applied to the bracket 26 from the leg portions 27a and 28a of the slider 24 via the steel balls 90 and the movement on the bracket 26.

[0013] In view of the above problems, an object of the present invention is to provide a linear drive device, a motor, and a linear drive device manufacturing method capable of reducing rattle with a more reasonable structure. [Solution to the problem]

[0014] To solve the problem, the invention is provided in the appended claims. The following description of aspects serves to provide a better understanding of the invention. One aspect of the present invention is to be able to set a movable range of a movable member to be wide even while reducing chatter. That is, one aspect of the present invention is a linear drive device including: a motor; a lead screw that rotates around an axis integral with an output shaft of the motor; a nut mechanism forming a feed screw mechanism together with the lead screw; a guide shaft extending parallel to the lead screw; a movable member movably supported by the guide shaft and driven in an axial direction of the lead screw by the motor via the nut mechanism; and a bracket including a first plate portion fixed to a driven-side end surface of a lead screw-side housing of the motor, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and a bearing rotatably supporting the distal end side of the lead screw held on the second plate portion, wherein the nut mechanism includes a first nut portion that is not relatively movable in an axial direction of the lead screw with respect to the movable member, a second nut portion that is relatively movable in the axial direction with respect to the movable member toward the first plate portion side of the first nut portion, and a first spring that biases the second nut portion in the axial direction.

[0015] In the present invention, since the movable member is driven via the guide shaft and the lead screw supported by the bracket, rattling is difficult to occur when driving the movable member. Furthermore, since the nut mechanism including two nut portions (the first nut portion and the second nut portion) and the first spring are used, rattling of the nut portions with respect to the lead screw can be suppressed. Also in this case, the first nut portion on the opposite side from the motor and the first plate portion between the two nut portions are not relatively movable with respect to the movable member.Since the driven element is mounted in a position that is biased sideways relative to the motor and the first plate portion when the driven element is mounted on the movable element, it is possible to reduce rattling in a more suitable structure. For example, it is possible to expand the movable range of the movable element.

[0016] In the present invention, it is possible to adopt an aspect in which the lead screw and the guide shaft are arranged at positions that overlap in the vertical direction. According to such an aspect, it is possible to receive a load of the movable member in a stable state via the guide shaft and the lead screw. Thus, it is possible to stably drive the movable member and the driven member, and accordingly reduce rattling.

[0017] In the present invention, it is possible to adopt an aspect in which a mounting portion of the driven element is provided in the movable element, and a center of the mounting portion overlaps the lead screw and the guide shaft in the vertical direction. According to such an aspect, it is possible to receive loads of the movable element and the driven elements in a stable state via the guide shaft and the lead screw in a state in which the driven element is mounted in the movable element.

[0018] In the present invention, it is possible to adopt an aspect in which the movable member is formed with plane symmetry with respect to a virtual plane defined by a central axis of the lead screw and a central axis of the guide shaft. According to such an aspect, it is possible to receive the loads of the movable member and the driven members via the guide shaft and the lead screw in a stable state.

[0019] In the present invention, it is possible to adopt an aspect in which a switch is adapted to detect the movable member held in the bracket. According to such an aspect, since the switch can be arranged at a suitable position relative to the bracket, it is possible to accurately detect the approach of the movable member to the motor and the first plate portion.

[0020] In the present invention, it is possible to adopt an aspect in which the switch is held in the first plate portion. In this case, it is possible to adopt an aspect in which a fourth plate portion bent toward the second plate portion is provided in an end portion of the first plate portion on the opposite side to the third plate portion, and the switch is held in the fourth plate portion.

[0021] In the present invention, it is possible to adopt an aspect in which the fourth plate portion is parallel to the third plate portion.

[0022] In the present invention, it is possible to adopt an aspect in which the switch is a contact switch that detects the movable member in accordance with the contact with the movable member. In such a configuration, the effect of placing the switch at a suitable position relative to the bracket is significant.

[0023] In the present invention, it is possible to adopt an aspect in which a plate portion protruding to the side opposite to the third plate portion and capable of coming into contact with the switch is provided in the movable member.

[0024] In the present invention, it is possible to adopt an aspect in which the first spring is a spiral spring in which the lead screw passes through an inner side thereof, the second nut portion includes a cylindrical portion having internal threads formed on an inner peripheral surface, the internal threads meshing with the lead screw, and a rectangular flange portion formed at an end portion of the cylindrical portion on the side opposite to the coil spring, and the flange portion receives a first end portion of the first spring.

[0025] In the present invention, it is possible to adopt an aspect in which, in the second nut portion, a groove-like concave portion in which the first end portion is received is formed on a surface of the flange portion on the coil spring side. According to such an aspect, it is possible to prevent the first end portion of the coil spring from detaching from the second nut portion.

[0026] In the present invention, it is possible to adopt an aspect in which the groove-like concave portion has a depth equal to or greater than half a diameter of a wire material constituting the spring.

[0027] In the present invention, it is possible to adopt an aspect in which the groove-like concave portion is formed between the cylindrical portion and a projection projecting from the flange portion to the coil spring side.

[0028] In the present invention, it is possible to adopt an aspect in which the first spring is a coil spring in which the lead screw passes through an inner side thereof, the first nut portion includes a cylindrical portion having internal threads formed on an inner peripheral surface, the internal threads meshing with the lead screw, and a rectangular flange portion formed at an end portion of the cylindrical portion on the side opposite to the coil spring, the movable member includes a support plate portion disposed between the coil spring and the flange of the first nut portion, and against which a second end portion of the coil spring on the first nut portion side and a surface of the first nut portion on the coil spring side of the flange stopper abut, a notch-like opening portion,which is directed toward an open end in a direction perpendicular to the axial direction, is formed in the support plate portion, the cylindrical portion of the first nut portion is located on an inner side of the opening portion, and an inner peripheral surface located on the side opposite the open end side of the opening portion is a circular arc-shaped surface that is bent along an outer peripheral surface of the cylindrical portion of the first nut portion and abuts against the cylindrical portion of the first nut portion. According to such an aspect, even when the second end portion of the coil spring is supported by the movable member, the second end portion of the coil spring can be supported by the movable member over a wide range in the circumferential direction.

[0029] In the present invention, it is possible to adopt an aspect in which a mark aligning an angular position of the first nut portion and the second nut portion is provided in each of the first nut portion and the second nut portion. According to such an aspect, it is possible to precisely adjust the angular positions of the first nut portion and the second nut portion based on the marks. Therefore, even when a pitch of the external threads of the lead screw (pitch of the internal threads of the nut portion) is increased, it is possible to attach the first nut portion and the second nut portion at an appropriate phase with respect to the lead screw.

[0030] In the present invention, it is possible to adopt an aspect in which the marking is located on the side toward which the open end is directed in each of the first nut portions and the second nut portions. According to such an aspect, the markings are easy to visually recognize.

[0031] In the present invention, it is possible to adopt an aspect in which the marking is a protruding ridge. According to such an aspect, the markings are easy to visually recognize.

[0032] In the present invention, it is possible to adopt an aspect in which a first shaft hole into which the guide shaft is fitted is formed in the first plate portion, a second shaft hole into which the guide shaft is fitted is formed in the second plate portion, the guide shaft is pressed into one of the first shaft hole and the second shaft hole, an inner diameter of the other shaft hole is larger than an outer diameter of the guide shaft, and a portion of the guide shaft in the circumferential direction abuts against an inner peripheral surface of the other shaft hole, and another portion in the circumferential direction abuts against a partially overhanging portion of the inner peripheral surface of the other shaft hole.Since the guide shaft is arranged relative to the position where a portion of the guide shaft circumferentially engages the inner peripheral surface of the other shaft hole, it is possible to provide the guide shaft at a suitable location if the position where a circumferential portion of the guide shaft engages the inner peripheral surface of the other shaft hole is precisely formed with respect to one shaft hole. For example, it is possible to improve the parallelism accuracy between the lead screw and the guide shaft.

[0033] In the present invention, it is possible to adopt an aspect in which the portion abuts against an inner peripheral surface of the other shaft hole on the lead screw side in the circumferential direction of the guide shaft, and the other portion abuts against the overhanging portion formed by caulking on the side opposite to the lead screw in the circumferential direction of the guide shaft.

[0034] In the present invention, it is possible to adopt an aspect in which the third plate portion extends parallel to the guide axis, and the movable member includes a pair of buffer arm portions with flexibility projecting toward opposite sides, with the lead screw interposed therebetween to oppose the third plate portion, and a leg portion bent toward the third plate portion from a distal end of each of the two buffer arm portions and abutting against the third plate portion. According to such an aspect, it is possible to suppress the amount of rotation (rotation angle) to be small because the leg portion abuts against the plate surface of the bracket when the movable member attempts to rotate.Furthermore, by providing the buffer arm portion, it is possible to absorb shock because the buffer arm portion is bent when the leg portion abuts the plate surface of the bracket, so that no abnormal noise is generated. Thus, it is possible to effectively reduce rattling in the circumferential direction because there is a clearance between the movable member and the lead screw at the time of engine start and stop, for example, through a simple structure with an increase in the number of components. Thus, it is possible to avoid a fault from the occurrence of rattling.

[0035] In the present invention, in the output shaft, an end portion opposite the output or driven side, which is located on the side opposite the bracket, protrudes from an end surface opposite the output side, which is located on the side opposite the bracket of the housing, a second spring in the form of a bent plate, which presses the end portion of the output shaft opposite the output side toward the output side in which the bracket is located, is fixed to the end surface opposite the output side, the end portion opposite the output side is formed by a flat surface or a spherical surface, and the second spring includes a fixing portion fixed to the end surface of the housing opposite the output side, a biasing portion which is bent to be spaced from the output shaft and extends to the side,in which the opposite output-side end portion is located from the fixing portion, and a pressing portion extending in a direction in which the pressing portion is spaced from the end portion opposite the output side, while being bent in a direction opposite to the biasing portion to abut the end portion opposite the output side of the biasing portion. According to such an aspect, when the pressing portion is brought into line contact or point contact with the end portion (opposite the output-side end surface) formed on the flat surface or the spherical surface of the output shaft protruding from the outside of the one end surface (end portion opposite the output side) of the housing, it is possible toThe output shaft (the lead screw) is pressed in the axial direction with the elastic force of the preloading portion of the second spring in a circular arc shape. Accordingly, it is possible to suppress, for example, chattering caused between the threads of the lead screw, and thus reduce operating errors. Furthermore, even if the height of the output shaft protrusion from one end face (opposite the output-side end face) of the housing is different, the output shaft can be constantly pressed in the axial direction. This makes it possible to suppress obstacles such as local wear caused by partial contact with the bearing due to the inclination of the pressing force from the second spring to the output shaft with respect to the axial direction or by noise generation.

[0036] In the present invention, it is possible to adopt an aspect in which a protrusion is provided in at least one of the first nut portion and the second nut portion, which protrusion abuts against a wall surface of the movable member in front of a corner of an outer peripheral surface of the nut portion when the nut portion attempts to rotate about the axis. According to such an aspect, even if a gap is formed between the wall surface of the movable member and the nut portion, the protrusion of the nut portion abuts against the wall surface of the nut receiving portion at the time of starting and stopping the motor. Thus, it is possible to realize prevention or greatly reduce the generation of abnormal noise that occurs between the nut portion and the movable member.

[0037] An object of another embodiment of the linear drive device according to the present invention is to adequately suppress chattering by configuring such that loads of a movable member and a driven member are adequately applied to a guide shaft and a lead screw when the chatter of the movable member has been reduced by providing the guide shaft. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw that rotates about an axis integral with an output shaft of the motor; a nut portion that forms a feed screw mechanism together with the lead screw; a guide shaft that extends parallel to the lead screw; a movable member,which is movably supported by the guide shaft and driven by the motor via the nut portion in an axial direction of the lead screw; and a bracket including a first plate portion fixed to a driven-side end surface of a housing of the motor located on the lead screw side, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and a bearing rotatably supporting the distal end side of the lead screw, which is held on the second plate portion, wherein the lead screw and the guide shaft are arranged at positions overlapping in a vertical direction. According to such an aspect, since the movable member is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for rattle to occur.when driving the moving element. In addition, since the loads of a moving element and a driven element are applied accordingly to a guide shaft and a lead screw, it is possible to drive the moving element and the driven element stably and reduce chatter accordingly.

[0038] The aim of another aspect of the linear drive device according to the present invention is to appropriately mount a switch by reducing the rattling of a movable member through the use of a guide shaft and a lead screw supported by a bracket. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw rotating about an axis integral with an output shaft of the motor; a nut portion forming a feed screw mechanism together with the lead screw; a guide shaft extending parallel to the lead screw; a movable member movably supported by the guide shaft and driven by the motor via the nut portion in an axial direction of the lead screw; and a bracket including a first plate portion,which is fixed to a driven-side end surface of a housing of the motor located on the lead screw side, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and including a bearing that rotatably supports the distal end side of the lead screw held on the second plate portion, wherein a switch capable of detecting the movable element is held in the bracket. According to such an aspect, since the movable element is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for rattling to occur when driving the movable element. Furthermore, since the switch can be arranged at a suitable position with respect to the bracket, it is possible toto accurately detect the approach of the moving element to the motor and the first plate section.

[0039] The aim of another aspect of the linear drive device according to the present invention is to prevent the first spring from falling out of the nut portion when reducing the rattling of the nut portion using a nut mechanism having two nut portions and a first spring. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw that rotates around an axis integral with an output shaft of the motor; a nut mechanism that forms a feed screw mechanism together with the lead screw; a guide shaft that extends parallel to the lead screw; a movable member movably supported by the guide shaft and driven in an axial direction of the lead screw by the motor via the nut mechanism; and a bracket that includes a first plate portion,which is fixed to a driven-side end surface of a housing of the motor located on the lead screw side, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and including a bearing rotatably supporting the distal end side of the lead screw held on the second plate portion, wherein the nut mechanism includes a first nut portion that is not relatively movable in an axial direction of the lead screw with respect to the movable member, a second nut portion that is relatively movable in the axial direction with respect to the movable member, and a first spring that biases the second nut portion in the axial direction, wherein the first spring is a coil spring in which the lead screw passes through an inner side thereof,The second nut portion includes a cylindrical portion with internal threads that mesh with the lead screw and are formed on an inner peripheral surface, and a rectangular flange portion formed at an end portion of the cylindrical portion on the side opposite the coil spring. The flange portion accommodates a first end portion of the first spring. According to such an aspect, since the movable member is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for rattling to occur when driving the movable member. Furthermore, it is possible to reduce rattling between the nut portion and the lead screw by using the nut mechanism with the two nut portions and the first spring. In this case, since the first end portion of the coil spring is arranged around the cylindrical portion in the second nut portion,it is possible to prevent the first end section of the coil spring from detaching from the second nut section.

[0040] An object of another aspect of the linear drive device according to the present invention is to support an end portion of a first spring in a stable state with a movable member when reducing rattling of the nut portion with a nut mechanism having two nut portions and a first spring. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw that rotates about an axis integral with an output shaft of the motor; a nut mechanism that forms a feed screw mechanism together with the lead screw; a guide shaft that extends parallel to the lead screw; a movable member movably supported by the guide shaft and driven in an axial direction of the lead screw by the motor via the nut mechanism; and a bracket.which includes a first plate portion fixed to a driven-side end surface of a housing of the motor located on the lead screw side, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and a bearing rotatably supporting the distal end side of the lead screw held on the second plate portion, wherein the nut mechanism includes a first nut portion that is not relatively movable in the axial direction of the lead screw with respect to the movable member, a second nut portion that is relatively movable in the axial direction with respect to the movable member, and a first spring that biases the second nut portion in the axial direction, wherein the first spring is a coil spring,in which the lead screw extends through an inner side thereof, wherein the first nut portion includes a cylindrical portion with internal threads formed on an inner peripheral surface and meshing with the lead screw, and a rectangular flange portion formed at an end portion of the cylindrical portion on the side opposite the coil spring, wherein the movable member includes a support plate portion disposed between the coil spring and the flange of the first nut portion, and against which a second end portion of the coil spring on the side of the first nut portion and a surface of the first nut portion on the side of the coil spring of the flange stopper abut, a notch-like opening portion directed toward an open end in a direction perpendicular to the axial direction is formed in the support plate portion,and the cylindrical portion of the first nut portion is located on an inner side of the opening portion, an inner peripheral surface located on the side opposite the open end side of the opening portion is a circular arc-shaped surface curved along an outer peripheral surface of the cylindrical portion of the first nut portion and adjacent to the cylindrical portion of the first nut portion. According to such an aspect, since the movable member is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for chatter to occur when driving the movable member. Furthermore, it is possible to reduce chatter between the nut portion and the lead screw because the nut mechanism with the two nut portions and the first spring is used. Furthermore, even if the second end portion of the coil spring is supported by the movable member,the second end portion of the coil spring is supported by the movable member over a wide range in the circumferential direction.,

[0041] An object of another aspect of the linear drive device according to the present invention is to support an end portion of a first spring in a stable state with a movable member when reducing rattling of the nut portion with a nut mechanism having two nut portions and a first spring. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw that rotates about an axis integral with an output shaft of the motor; a nut mechanism that forms a feed screw mechanism together with the lead screw; a guide shaft that extends parallel to the lead screw; a movable member movably supported by the guide shaft and driven in an axial direction of the lead screw by the motor via the nut mechanism; and a bracket.which includes a first plate portion fixed to a driven-side end surface of a housing of the motor located on the lead screw side, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and a bearing rotatably supporting the distal end side of the lead screw held on the second plate portion, wherein the nut mechanism includes a first nut portion that is not relatively movable in the axial direction of the lead screw with respect to the movable member, a second nut portion that is relatively movable in the axial direction with respect to the movable member, and a first spring that biases the second nut portion in the axial direction, and a marker,which aligns an angular position of the first nut portion and the second nut portion, is provided in each of the first nut portions and the second nut portion. According to such an aspect, since the movable element is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for chatter to occur when driving the movable element. Furthermore, it is possible to reduce chatter between the nut portion and the lead screw because the nut mechanism with the two nut portions and the first spring is used. Furthermore, since the marks for aligning the angular positions of the first nut portion and the second nut portion are provided in each of the first nut portions and the second nut portion, it is possibleto precisely adjust the angular positions between the first nut section and the second nut section. Therefore, even if the pitch of the external threads of the lead screw (the pitch of the internal threads of the nut section) is increased, it is possible to install the first nut section and the second nut section at a suitable phase with respect to the lead screw.

[0042] The aim of another aspect of the linear drive device according to the present invention is to reduce chatter of a movable member having a guide shaft and a lead screw supported by a bracket, and to improve the accuracy of parallelism between the guide shaft and the lead screw. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw that rotates around an axis integrally with an output shaft of the motor; a nut portion that forms a feed screw mechanism together with the lead screw; a guide shaft that extends parallel to the lead screw; a movable member movably supported by the guide shaft and driven by the motor via the nut portion in an axial direction of the lead screw; and a bracket that includes a first plate portion,which is fixed to an output-side end surface of a housing of the motor located on the lead screw side, a second plate portion facing the first plate portion on a distal end side of the lead screw, and a third plate portion connecting the first plate portion to the second plate portion, and including a bearing that rotatably supports the distal end side of the lead screw held on the second plate portion, wherein a first shaft hole is formed in the first plate portion into which the guide shaft is inserted, a second shaft hole into which the guide shaft is inserted is formed in the second plate portion, the guide shaft is pressed into one of the first shaft hole and the second shaft hole, wherein an inner diameter of the other shaft hole is larger than an outer diameter of the guide shaft,and a portion of the guide shaft in the circumferential direction abuts an inner peripheral surface of the other shaft hole, and another portion in the circumferential direction abuts a partially overhanging portion of the inner peripheral surface of the other shaft hole. According to such an aspect, since the movable member is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for chatter to occur when driving the movable member. Furthermore, since the guide shaft is arranged with respect to the position where a circumferential portion of the guide shaft abuts the inner peripheral surface of the other shaft hole, it is also possible to provide the guide shaft at a suitable position if the position where a circumferential portion of the guide shaft abuts the inner peripheral surface of the other shaft hole is precisely formed with respect to one shaft hole. For example, it is possibleto improve the parallelism accuracy between the lead screw and the guide shaft.,

[0043] A problem of another aspect of the linear drive device according to the present invention is to simplify a structure to effectively reduce chatter of the movable member at the time of starting and stopping, for example, a motor. That is, another aspect of the linear drive device according to the present invention is a linear drive device including: a motor; a lead screw coaxially integrally formed with an output shaft of the motor; a nut meshing with the lead screw, arranged parallel to a guide shaft and spaced from the lead screw; a movable member movably provided on the guide shaft and to which the nut is non-rotatably attached; and a flat plate-like bracket having one end portion fixed to a housing of the motor, a plate surface extending parallel to the lead screw, and the other end portion,to which a bearing is attached that rotatably supports one end portion of the lead screw, wherein a buffer arm portion extends parallel to the plate surface of the bracket in a direction orthogonal to the axial direction or extends in a direction in which the buffer arm portion is gradually spaced from the plate surface toward a distal end, and protrudes toward the outside of the bracket, and a leg portion bent toward the plate surface side of the bracket from the distal end of the buffer arm portion and having a distal end portion abutting against the plate surface of the bracket are integrally formed in both side portions of the movable member in the axial direction of the lead screw. According to such an aspect, since the buffer arm portion extends in a direction parallel to the plate surface of the bracket or extends in a directionIn which the buffer arm portion is gradually spaced from the plate surface toward the distal end and protrudes toward the outside of the bracket, is provided in both side portions of the movable member, and the leg portion is bent toward the plate surface side of the bracket so that a distal end portion of the leg portion abuts the plate surface of the bracket and is integrally formed with the distal end of the buffer arm portion, it is possible to suppress the small amount of rotation (angle of rotation) caused by the leg portion abutting the plate surface of the bracket when the movable member attempts to rotate. In addition, since the buffer arm portion, which extends parallel to the plate surface of the bracket or extends in a direction in which the buffer arm portion is gradually spaced from the plate surface toward the distal end, is provided between the movable member and the leg portion,It is possible to absorb the shock caused by the buffer arm portion being bent when the leg portion abuts the plate surface of the bracket, preventing the generation of abnormal noise. This makes it possible to effectively reduce rattling in the circumferential direction, as a clearance between the slider and the lead screw at the time of engine start and stop, for example, is maintained. This allows for a simple structure with an increase in the number of components, thus preventing failure due to rattling.

[0044] In this case, it is possible to adopt an aspect in which a portion of the plate surface of the bracket in a region abutting against a distal end of the leg portion is formed by a half-punching process to protrude toward the leg portion. According to such an aspect, since the half-punching process to protrude toward the leg portion side (the top surface of the bracket) is performed in a portion in a region where the distal end of the leg portion abuts against the plate surface of the bracket, it is possible to improve the flatness of the portion at the time of the process and ensure stable travel without causing vertical shaking in the movable member.

[0045] Furthermore, it is possible to adopt an aspect in which one end of the output shaft is inserted through a bearing provided on one end surface of the housing, one end surface of which protrudes from the one end surface and is supported to be rotatable, and a second spring in the form of a flat, curved plate that presses the output shaft in the axial direction is provided on one end surface of the housing, wherein the one end surface of the output shaft is formed by a flat surface or a spherical surface, and the second spring is formed with a fixing portion formed in one end portion and fixed to the one end surface of the housing, a biasing portion formed by bending in a convex circular arc shape in the axial direction, and a pressing portion formed by bending in an inverse circular arc shape from the other end portion of the biasing portion.and an outer peripheral surface of the pressing portion abutting against the one end surface of the output shaft. According to such an aspect, since the pressing portion having an inverse circular arc shape is brought into line contact or point contact with the flat surface formed at the distal end surface or the spherical surface of the output shaft projecting from the one end surface of the housing to the outside by an elastic force of the biasing portion having an arc shape of the second spring, thereby pressing the output shaft (the lead screw) in the axial direction, it is possible to constantly press the output shaft in the axial direction even if the height of the projection of the output shaft from one end surface of the housing is different. This makes it possible toTo suppress obstacles such as local wear due to partial contact with the bearing by inclination of the pressing force from the second spring to the output shaft with respect to the axial direction or noise generation.

[0046] An object of one aspect of the motor according to the present invention is to suppress rattling or the like caused between the threads of the lead screw and reduce error at the time of operation by providing a second spring that constantly biases the output shaft in the axial direction. That is, a motor according to the present invention is a motor in which a rotor magnet is rotatably provided through a gap of an excitation coil mounted in a housing, and an end surface of an output shaft, which is integrally formed with a center of the rotor magnet and protrudes from one end surface of the housing, is biased toward the other end portion by a second spring provided on the end surface of the housing. One end surface of the output shaft is formed by a flat surface or a spherical surface, and the second spring is formed with a mounting portion.which is formed in one end portion and fixed to one end surface of the housing, a biasing portion formed by bending in a convex circular arc shape in the axial direction of the output shaft, and a pressing portion formed by bending in an inverse circular arc shape from the other end portion of the biasing portion and an outer peripheral surface of the pressing portion abutting against the one end surface of the output shaft. According to such an aspect, since the pressing portion having an inverse circular arc shape is brought into line contact or point contact with the distal end surface formed as a flat surface or the spherical surface of the output shaft projecting from the one end surface of the housing to the outside by an elastic force of the biasing portion having an arc shape of the second spring, thereby pressing the output shaft (the lead screw) in the axial direction, it is possibleThis suppresses rattling or the like caused between the threads of the lead screw and reduces errors during operation. Furthermore, even with varying protrusion heights of the output shaft, the output shaft can be consistently pressed in the axial direction by an end surface of the output shaft housing. This makes it possible to suppress obstacles such as local wear caused by partial contact with the bearing due to the inclination of the pressing force from the second spring to the output shaft with respect to the axial direction or by noise generation.

[0047] In this case, it is possible to adopt an aspect in which the linear drive device is formed with a lead screw coaxially integrally with the other end of the output shaft, a nut portion is engaged with the lead screw, a guide shaft is arranged parallel and at a distance from the lead screw, and a movable member is movably provided on the guide shaft and to which the nut portion is non-rotatably fixed, wherein a bracket having a flat plate, one end of which is fixed to the housing, and a bearing extending parallel to the lead screw and connected to the other end portion, which rotatably supports one end portion of the lead screw, is provided on the other end surface of the housing, and a buffer arm portion extending parallel to the plate surface of the bracket in a direction orthogonal to the axial direction or extending in a direction,In this linear drive device, a buffer arm portion is gradually spaced from the plate surface toward a distal end and protrudes toward the outside of the bracket, and a leg portion bent toward the plate surface side of the bracket from the distal end of the buffer arm portion and having a distal end portion abutting against the plate surface of the bracket are integrally formed in both axial direction side portions of the movable member. In such a linear drive device, a phenomenon arises in which the movable member rotates circumferentially around the lead screw as the center at the time of, for example, starting or reversing the motor due to a small clearance between the guide shaft and the through hole of the movable member through which the guide shaft is inserted. In this case, according to this aspect,Since the buffer arm portion extends in a direction orthogonal to the axis parallel to the plate surface of the bracket and protrudes to the outside of the bracket, is provided in both side portions of the movable member, and the leg portion is bent toward the plate surface side of the bracket so that a distal end of the leg portion abuts the plate surface of the bracket. It is integrally formed at the distal end of the buffer arm portion. It is possible to suppress the degree of rotation (angle of rotation) that is small due to the leg portion abutting the plate surface of the bracket when the movable member attempts to rotate. In addition, since the buffer arm portion is provided parallel to the plate surface of the bracket between the movable member and the leg portion, the buffer arm portion can be bent and the shock absorbed when the leg portion abuts the plate surface of the bracket. This makes it possible toto prevent the occurrence of abnormal noises.

[0048] Furthermore, it is possible to adopt an aspect in which a portion of the plate surface of the movable member in a region abutting a distal end portion of the leg portion is formed to protrude toward the leg portion by a half-punching process. According to such an aspect, since the half-punching process to protrude toward the leg portion side (the upper surface of the bracket) is performed in a portion in a region where the distal end of the leg portion abuts the plate surface of the bracket, it is possible to improve the flatness of the portion at the time of the process and ensure stable travel without causing vertical shaking in the movable member.

[0049] Another aspect of the linear drive device according to the present invention is a linear drive device including: a lead screw rotated and driven by a motor; an n-polygonal nut, of which an outer peripheral surface screwed to the lead screw is formed as n square surfaces; a guide shaft arranged parallel to and spaced from the lead screw; and a slide plate movably provided on the guide shaft, and a nut receiving portion is formed into which the nut is inserted and rotation of the nut is blocked by an inner wall; wherein a projection, an outer surface of which is formed as a three-dimensional convex curved surface that comes into point contact with the inner wall of the nut receiving portion and has a height dimension that enablesAt the time of rotation of the nut, a protrusion is provided on a square surface of at least one of the outer peripheral surfaces of the nut facing the inner wall of the nut receiving portion, which protrusion is provided on the outer peripheral surface of the nut, which faces the inner wall of the nut receiving portion, and which is provided on the outer peripheral surface of the nut with a height dimension that allows the outer surface to come into point contact with the inner wall of the nut receiving portion and which is provided on the outer peripheral surface of the nut facing the inner wall of the nut receiving portion, at the time of rotation of the nut, it is possible to prevent the generation of abnormal noise generated between the nut and the sliding plate by the protrusion of the nut abutting the inner wall of the nut receiving portion at the time of starting or stopping the engine.to prevent or strongly suppress even if a gap is formed between the nut receiving portion and the nut portion.

[0050] In this case, the nut is formed with a square outer shape, and the protrusions are formed at both end portions in the rotational direction on the two rectangular surfaces facing the axis of the nut. According to this aspect, it is possible to make the protrusion located on the opposite side of the axis abut the inner wall of the nut receiving portion in a balanced manner at the time of motor start and stop.

[0051] Another aspect of the present invention is a manufacturing method of a linear drive device, wherein the linear drive device includes a motor, a lead screw that rotates about an axis integral with an output shaft of the motor, a nut mechanism that forms a feed screw mechanism together with the lead screw, a guide shaft that extends parallel to the lead screw, and a movable member movably supported by the guide shaft, wherein the nut mechanism includes a first nut portion disposed in a nut receiving portion of the movable member so as not to be relatively movable in an axial direction of the lead screw with respect to the movable member, a second nut portion disposed so as to be relatively movable in the axial direction from the first nut portion, and a first spring that biases the second nut portion in the axial direction.and the movable member includes a support plate portion located between the first nut portion and the first spring in the nut receiving portion, wherein in the manufacturing method of the linear drive device, a notch-like opening portion directed toward an open end in a direction orthogonal to the axial direction is provided in the support plate portion, a device in which a notch with one end as an open end is formed, and in a step of assembling the first nut portion in the nut receiving portion, the first spring is arranged between the first nut portion and the second nut portion attached to the lead screw, the device is arranged between the first spring and the second spring, and then the lead screw and the movable member are caused to approach each other in a direction orthogonal to the axial direction, and the support plate portion pushes the device so thatthat the lead screw is released from the notch through the open end of the notch and inserted into the inside of the opening section through the open end of the opening section., [Brief description of the characters] Fig. 1 is a perspective view of an embodiment of a linear drive device to which the present invention is applied. Fig. 2 is an exploded perspective view illustrating a state in which a movable member and a switch are removed from the Fig. 1 shown linear drive device must be removed. Fig. 3 is a front view illustrating an embodiment of a linear drive device according to the present invention. Fig. 4 is a bottom view of the linear drive device when the Fig. 3 shown bracket is removed. Fig. Fig. 5 is an illustrative view when the linear drive device is viewed at a position indicated by a line AA in Fig. 3 is marked. Fig. 6 is an enlarged view of a section B in Fig. 5. Fig. 7(a) and Fig. 7(b) are illustrative views of a second spring shown in Fig. 1 is shown. Fig. 8(a) and Fig. 8(b) are illustrative views of a second spring different from that shown in Fig. 7(a) and Fig. 7(b) shows the second spring. Fig. Fig. 9 is an illustrative view when the linear drive device is viewed at a position indicated by a line FF in Fig. 3 is marked. Fig. 10 is a perspective view when a slider of the Fig. 2 shown movable element in an oblique downward direction and viewed from the first plate section sides. Fig. 11 is a perspective view when a state in which the Fig. 2 is attached to the slider of a movable member, viewed in an oblique downward direction and from the first plate portion side. Fig. 12 is an exploded perspective view of a state in which the nut mechanism is removed from the Fig. 11 shown state is removed. Fig. 13 is a perspective view showing a state in which the Fig. 2 is connected to the slider of the movable member, viewed in an oblique downward direction and from the second plate section side. Fig. 14 is an exploded perspective view of a state in which the nut mechanism is removed from the Fig. 13 shown state is removed. Fig. 15 is a perspective detail view of the Fig. 2 shown nut mechanism. Fig. 16 is a cross-sectional view of the Fig. 2 shown nut mechanism. Fig. 17 is an illustrative view showing a fixing structure of a guide shaft in the linear drive device shown in Fig. 1 is shown. Fig. 18 is an illustrative view showing a manufacturing method of the linear drive device to which the present invention is applied. Fig. 19(a) and Fig. 19(b) are perspective views of a nut portion used for a linear drive device according to a modification example of the present invention. Fig. 20(a) and Fig. 20(b) are illustrative views schematically showing a state in which the Fig. 19(a) and Fig. 19(b) was rotated around an axis of the lead screw. Fig. 21(a) and Fig. 21(b) are illustrative views schematically showing a state in which the nut portion is rotated around an axis of the lead screw in a case where a Fig. 19(a) and Fig. 19(b) projection is not provided. Fig. 22 is a front view when a bracket is removed in a linear drive device according to a modification example of the present invention. Fig. 23 is an illustrative view of a linear drive device in a prior art example. Fig. 24 is an illustrative view of a movable member used for the linear drive device shown in Fig. 23 shown. [Description of the embodiments]

[0052] A linear drive device, a motor, and a manufacturing method of a linear drive device to which the present invention is applied will be described with reference to the figures. (Configuration of the linear drive device 100)

[0053] Fig. 1 is a perspective view of one embodiment of a linear drive device 100 of the present invention. Fig. Fig. 2 is an exploded perspective view in a state in which a movable member 6 and a switch 18 are removed from the Fig. 1 shown linear drive device 100 can be removed. Fig. 3 is a front view illustrating an embodiment of the linear drive device according to the present invention. Fig. 4 is a bottom view of the linear drive device 100 when a Fig. 3 shown bracket is removed.

[0054] The Fig. The linear drive device 100 shown in FIGS. 1 to 4 schematically includes a lead screw 2 rotatably driven by a motor (stepping motor in the embodiment) 1, a nut portion 3 (a first nut portion 31 and a second nut portion 32) that forms a feed screw mechanism by meshing with the lead screw 2, a guide shaft 5 arranged parallel to the lead screw 2 and having both end portions supported by a bracket 4, and a movable member 6 movably provided on the guide shaft 5. A nut receiving portion 6a, into which the lead screw 2 is inserted and which non-rotatably receives the nut portion 3 (the first nut portion 31 and the second nut portion 32), is formed in the movable member 6. Furthermore, a shaft hole 612 through which the guide shaft 5 passes is formed in the movable member 6.The two nut portions 3 (the first nut portion 31 and the second nut portion 32) constitute a nut mechanism 30 together with a first spring 35 disposed between the first nut portion 31 and the second nut portion 32. Although not illustrated, a rotor magnet in the motor 1 is rotatably disposed through a gap with an excitation coil in a housing 8, and an output shaft 7 is fixed to a center of the rotor magnet.

[0055] In the motor 1, one end portion (the end portion opposite the output side) of the output shaft 7 is fitted into a bearing 9 provided on one side of the end surface 8a (the end surface opposite the output side) of the housing 8, and a rear end portion 7a is rotatably supported in the state protruding from the housing 8. The lead screw 2 is coaxially formed on an outer peripheral surface on the distal end (the other end) side of the output shaft 7 of the motor 1. Therefore, the lead screw 2 rotates integrally with the output shaft 7. Therefore, the movable member 6 can be linearly driven by the motor 1 via the nut portion 3 (nut mechanism 30).

[0056] The bracket 4 is formed by bending a flat plate member and includes a first plate portion 41 fixed to the other end surface 8b (driven-side end surface) on the lead screw 2 side of the housing 8 of the motor 1, a second plate portion 42 facing the first plate portion 41 on the distal end side of the lead screw 2, and a third plate portion 43 connecting the first plate portion 41 to the second plate portion 42. A bearing 10 for rotatably supporting the distal end side of the lead screw 2 is held in the second plate portion 42. Mounting holes 431 for connecting the linear actuator 100 to a device body are formed at both side end portions of the third plate portion 43.

[0057] The first spring 35, which biases the second nut portion 32 in the axial direction, is provided between the second nut portion 32 accommodated in the nut receiving portion 6a and an inner wall of the nut receiving portion 6a, and the occurrence of a failure due to gear backlash between the lead screw 2 and the second nut portion 32 is prevented by the first spring 35. (Configuration of the buffer arm section 13 or the like)

[0058] Fig. Fig. 5 is an illustrative view when the linear drive device 100 is viewed at a position indicated by a line AA in Fig. 3 is marked. Fig. 6 is an enlarged view of a section B in Fig. 5. As in the Fig. 5 and Fig. 6, a pair of buffer arm portions 13 aligned parallel to the plate surface of the third plate portion 43 of the bracket 4 in a direction orthogonal to the axis L of the lead screw 2, and a leg portion 14 bent toward the plate surface side of the third plate portion 43 of the bracket 4 from the distal ends of the respective buffer arm portions 13 in the pair so that a distal end abuts against the plate surface of the third plate portion 43 of the bracket 4, are integrally formed in both side portions of the movable member 6. The buffer arm portion 13 is formed with a length dimension in which the leg portion 14 is located on the outer side with respect to both side portions of the movable member 6 and has flexibility.

[0059] The third plate portion 43 is half-punched, so that a portion 15 in an area where a distal end of the leg portion 14 abuts protrudes from the leg portion 14 (upper surface). Therefore, in the third plate portion 43, a lower portion on the back side of the portion 15, where the distal end of the leg portion 14 abuts, is a shallow concave portion 15a. A half-punch process is a known sheet metal working in which a die having an opening corresponding to the portion 15 formed therein is disposed on the upper surface of the bracket 4, a rectangular punch corresponding to the portion 15 is disposed on the lower surface, and the portion 15 is pressed against the upper surface to be deformed by the punch. In the embodiment, a mold is also disposed on the upper surface corresponding to the portion 15, and the half-punch process is performed with the portion 15 sandwiched between the mold and the punch.

[0060] According to the linear drive device 100 having such a configuration, in both side portions in the moving direction of the movable member 6, a buffer arm portion 13 extending in a direction orthogonal to the axis parallel to the plate surface of the bracket 4 and protruding toward the outside of the bracket 4, and a leg portion bent from the distal end of the shock-absorbing arm portion 13 toward the plate surface side of the bracket 4 and having a distal end contiguous with the plate surface of the bracket 4 are integrally formed. Therefore, even when a rotational force acts on the movable member 6, for example, at the time of starting or reversing the motor, the leg portion 14 abuts the plate surface of the bracket 4, so that the rotational effort (rotation angle) is suppressed to be small.

[0061] In addition, the buffer arm portion 13 is provided parallel to the plate surface of the bracket 4 between the leg portions 14 of the movable member 6. Therefore, when the leg portion 14 abuts against the plate surface of the bracket 4, the buffer arm portion 13 is bent and absorbs shock, thus preventing abnormal noise from being generated. Furthermore, since the half-punching process for protruding toward the leg portion 14 side (the top surface of the bracket 4) is performed on the portion 15 in a region where the distal end of the leg portion 14 abuts the plate surface of the bracket 4, it is possible to improve the flatness of the portion 15. This makes it possible to ensure stable travel even when the movable member 6 shakes up and down.

[0062] Note that although the buffer arm portion 13 extends in a direction orthogonal to the axis and parallel to the plate surface of the bracket 4, an aspect in which the buffer arm portion 13 extends in a direction in which the buffer arm portion 13 is gradually spaced from the third plate portion 43 toward the distal end side and protrudes toward the outside of the bracket 4 may be adopted. That is, the buffer arm portion 13 may be inclined toward the plate surface side of the third plate portion 43 of the bracket 4 and extend in a direction intersecting the axis L. Furthermore, the buffer arm portion 13 may be curved and include the buffer arm portion 13 with elasticity and the leg portion 14 abutting against the plate surface of the bracket 4 from the buffer arm portion 13.The buffer arm portion 13 may have a shape that is deformed when the leg portion 14 abuts against the plate surface and has a shape with elastic force. (Configuration of the second spring 12)

[0063] Fig. 7(a) and Fig. 7(b) are illustrative views of the Fig. 1 shown second spring 12, Fig. 7(a) is an enlarged view of a connected portion of the second spring 12, and Fig. 7(b) is an enlarged view when a position of the same output shaft 7 is changed. Fig. 8(a) and Fig. 8(b) are illustrative views of the second spring 11, which differs from the one shown in Fig. 7(a) and Fig. 7(b) shown second spring 12, Fig. 8(a) is an enlarged view of the connected portion of the second spring 11, and Fig. 8(b) is an enlarged view when the position of the same output shaft 7 also changes.

[0064] As in Fig. As shown in Fig. 7(a), between one end surface 8a of the housing 8 of the motor 1 and the rear end portion 7a of the output shaft 7, a second spring 12 is provided for biasing the output shaft 7 (the lead screw 2) in a direction of the axis L toward the bearing 10 side of the bracket 4. That is, when a moving direction of the movable member 6 is switched by reversing the motor 1, a time delay occurs in the movement of the movable member 6 due to a gap between the threaded rods of the lead screw 2 and the nut portion 3, and an error occurs. Thus, the second spring 12, which urges the output shaft 7 in the direction of the axis L, is provided on one end surface 8a of the housing 8 of the motor 1, suppressing a positional deviation in the direction of the axis L due to external forces such as chatter and vibration between the threads of the lead screw 2 and reducing an error at the time of operation.

[0065] In the embodiment, the second spring 12 includes a fixing portion 12c fixed to one end surface 8a of the housing 8, a biasing portion 12a extending from the fixing portion 12c to one end side of the rear end portion 7a of the output shaft 7 and biasing the output shaft 7 to the other end side, and a pressing portion 12b abutting the rear end portion 7a of the output shaft 7 from the biasing portion 12a. In the second spring 12, the fixing portion 12c and the biasing portion 12a have a constant plate width, but a plate width of the pressing portion 12b is smaller than a plate width of the fixing portion 12c and the biasing portion 12a. Furthermore, the plate width of the pressing portion 12b is larger than the rear end portion 7a of the output shaft 7.In the embodiment, the second spring 12 is formed by bending a leaf spring, wherein the fixing portion 12c which is clamped and fixed between the bearing 10 and the one end surface 8a of the housing 8 is formed in one end portion and is formed in an S-shape with a biasing portion 12a formed by bending in a convex circular arc shape in the direction of the axis L from the fixing portion 12c, and a pressing portion 12b formed by bending in an inverse circular arc shape from the other end portion of the biasing portion 12a.

[0066] That is, the second spring 12 includes the fixing portion 12c fixed to the one end surface 8a of the housing 8, the biasing portion 12a bent to be spaced from the output shaft 7 and extending from the fixing portion 12c to the side where the rear end portion 7a (the opposite output side end portion) of the output shaft 7 is located, and the urging portion 12b extending in a direction in which the urging portion 12b is spaced from the rear end portion 7a while being bent in the direction opposite to the biasing portion 12a so that the urging portion 12b abuts against the rear end portion 7a of the biasing portion 12a.

[0067] Furthermore, in the output shaft 7, the rear end portion 7a, which protrudes from one end surface 8a of the housing 8 to the outside, is formed with a flat or spherical surface. The second spring 12 is connected in a state where an outer peripheral surface of the pressing portion 12b abuts against the rear end portion 7a of the output shaft 7 by line contact when the rear end portion 7a is a flat surface, and by point contact when the rear end portion 7a is a spherical surface, and the output shaft 7 is pressed in the axial direction by an elastic force of the biasing portion 12a.

[0068] In the linear drive device 100 having such a configuration, the rear end portion 7a of the output shaft 7, which protrudes from one end surface 8a of the housing 8 to the outside, is formed into a flat surface or a spherical surface, and the pressing portion 12b in an inverted circular arc shape abuts against the rear end portion 7a by line contact by an elastic force of the biasing portion 12a having an arc shape in the second spring 12, whereby the output shaft 7 (the lead screw 2) is constantly pressed in the axial direction. Therefore, the output shaft 7, as shown in Fig. 7(b), even if the projection of the output shaft 7 from the one end surface 8a of the housing 8 is different or changes during operation, they are constantly pressed in the axial direction.

[0069] This makes it possible to suppress obstacles such as local wear of the bearing 9 due to partial contact with the bearing 9 due to inclination of the pressing force from the second spring 12 to the output shaft 7 with respect to the axial direction or due to noise generation.

[0070] Meanwhile, as shown in a reference example in Fig. 8(a), a configuration is also conceivable in which the output shaft 7 is preloaded by the second spring 11 in the form of a flat, curved plate. In this case, if the position of the output shaft 21, as shown in Fig. 8(b), due to a manufacturing defect of components such as the output shaft 7, the lead screw 2, or the bracket 4, or a movement of the output shaft 7 at the time of reversing the motor 1, a pressing direction of the second spring 11 is inclined with respect to the axis of the output shaft 21. Therefore, there is a fear that the output shaft 7 constantly partially abuts against the bearing 9, thereby shortening the service life of the bearing 9 due to local wear, or that the output shaft 7 collides with one side of the bearing 9 when starting or stopping the motor 1, thereby generating noise. According to the patent application filed with reference to Fig. 7(a) and Fig. However, with the second spring 12 described in Fig. 7(b), it is difficult to solve the above-mentioned problem.

[0071] Note that although the pressing portion 12b can be formed into an S-shape in the embodiment, an abutting portion between the output shaft 7 and the second spring 12 can only be bent (must not be formed into an S-shape). Moreover, the biasing portion 12a is formed for bending into a convex circular arc shape, but is not limited thereto, and the biasing portion 12a may have a shape with a biasing force toward the other end side. (Configuration of switch 18)

[0072] As in Fig. 1, a terminal block 16 is formed in a housing portion of the motor 1, and a circuit board 17 is attached to the terminal block 16. A switch 18 that detects the approach of the movable member 6 is electrically connected to the circuit board 17. The switch 18 is directly attached to the bracket 4. More specifically, the first plate portion 41 in the bracket 4 includes a fourth plate portion 410 in which an end portion on the side opposite the third plate portion 43 is bent toward the second plate portion 42 and extends parallel to the third plate portion 43, and the switch 18 is attached to the fourth plate portion 410. Here, the switch 18 is a contact switch 18a that detects the movable member 6 according to contact with the movable member 6, and a contact portion 180 faces the movable member 6.

[0073] In the linear drive device 100 configured as described above, since the movable member 6 is driven using the guide shaft 5 and the lead screw 2 supported by the common bracket 4, chatter is difficult to occur when driving the movable member 6. Since the switch 18 is fixed to the bracket 4, the switch can be arranged at a suitable position with respect to the bracket 4. Thus, it is possible to accurately detect the approach of the movable member 6 to the motor 1 and the first plate portion 41. Since the switch 18 is the contact switch 18a that detects the movable member 6 according to the contact with the movable member 6, the effects of arranging the switch 18 at a suitable position with respect to the bracket 4 are significant. (Configuration of the movable element 6)

[0074] Fig. Fig. 9 is an illustrative view when the linear drive device 100 is viewed at a position indicated by a line FF in Fig. 3 is marked. In Fig. 2, the movable element 6 includes a slider 61 (a sliding plate) which Fig. 2, and a cover 62 connected to the slider 61. Between the slider 61 and the cover 62 in a state where the slider 61 and the cover 62 are connected to each other, a concave mounting portion 60 in which a driven member (not shown) is mounted is formed, and a load of the driven member is applied to an inner surface located in a direction of the axis L of the mounting portion 60. In the slider 61, a plate portion 619 is formed, which abuts against the contact portion 180 of the switch 18 (the contact type switch 18a) when the movable member 6 approaches the motor 1 and the first plate portion 41.An end portion of the plate portion 619 on the side where the mounting portion 60 is located is inclined obliquely upward and configured to avoid interference with the driven element disposed in the mounting portion 60. Therefore, it is easy to mount the driven element in a state where the driven element is inclined obliquely along a surface on which the motor 1 is located with respect to the mounting portion 60. In this case, the driven element causes a load to be generated in the mounting portion 60 on the motor 1 side.

[0075] As in Fig. 9, the lead screw 2 and the guide shaft 5 are arranged at positions overlapping in the vertical direction V. Furthermore, in the movable member 6, a center of the attachment portion 60 overlaps the lead screw 2 and the guide shaft 5 in the vertical direction V. In the embodiment, the guide shaft 5 is arranged at a position immediately above the lead screw 2, and the slider 61 and the cover 62 are each formed with plane symmetry with respect to a virtual plane P defined by a center axis (axis L) of the lead screw 2 and a center axis L5 of the guide shaft 5. Therefore, the movable member 6 is formed with plane symmetry with respect to the virtual plane P.

[0076] Therefore, a load of the movable member 6 and the driven member is applied to the guide shaft 5 and the lead screw 2 accordingly to lie along the virtual plane P. This makes it possible to stably drive the movable member 6 and the driven member and reduce chatter accordingly. (Configuration of the nut mechanism 30)

[0077] Fig. 10 is a perspective view when the slider 61 of the Fig. 2 shown movable element 6 in an oblique downward direction and viewed from the first plate section 41 side. Fig. 11 is a perspective view when a state in which the Fig. 2, the nut mechanism 30 is connected to the slider 61 of the movable member 6, viewed obliquely downward and from the side of the first plate portion 41. Fig. 12 is an exploded perspective view in a state in which the nut mechanism 30 is removed from the Fig. 11 shown state is removed. Fig. 13 is a perspective view when a state in which the Fig. 2, the nut mechanism 30 is connected to the slider 61 of the movable member 6, viewed in an oblique downward direction and from the side of the second plate portion 42. Fig. 14 is an exploded perspective view in a state in which the nut mechanism 30 is removed from the Fig. 13 shown state is removed.

[0078] As in Fig. 10, in the slider 61, in the nut receiving portion 6a in which the nut mechanism 30 is housed, three plate portions (a first support plate portion 616, a second support plate portion 617, and a third support plate portion 618) are formed sequentially to the side where the second plate portion 42 is located from the side where the first plate portion 41 of the bracket 4 is located, between the mutually facing side walls 613 and 614 and a space separated by the first support plate portion 616, the second support plate portion 617, and the third support plate portion 618, a space in which each of the two nut portions 3 is disposed. Opening portions 616a, 617a, and 618a through which the lead screw 2 passes are formed in the first support plate portion 616, the second support plate portion 617, and the third support plate portion 618.

[0079] In this embodiment, the first nut portion 31 is arranged between the second support plate portion 617 and the third support plate portion 618, as shown in the Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 13 and Fig. 14. Furthermore, the second nut portion 32 is arranged between the first support plate portion 616 and the second support plate portion 617. Here, a distance between the side walls 613 and 614 is substantially equal to a width dimension of the first nut portion 31 and the second nut portion 32. Therefore, when the movable member 6 rotates about the axis L, both the first nut portion 31 and the second nut portion 32 abut the side walls 613 and 614. Therefore, both the first nut portion 31 and the second nut portion 32 are circumferentially non-rotatable with respect to the movable member 6.

[0080] A distance between the second support plate portion 617 and the third support plate portion 618 is substantially equal to a dimension in the axis L direction of the first nut portion 31. Therefore, the first nut portion 31 is arranged in the nut receiving portion 6a of the movable member 6 so as not to be relatively movable in the axis L direction with respect to the movable member 6. On the other hand, a distance between the first support plate portion 616 and the second support plate portion 617 is sufficiently larger than the dimension in the axis L direction of the second nut portion 32. Therefore, the second nut portion 32 is arranged in the nut receiving portion 6a of the movable member 6 so as to be relatively movable in the axis L direction with respect to the movable member 6.The first spring 35 is arranged between the second nut portion 32 and the second support plate portion 617, and the second nut portion 32 is biased in the direction of the axis L by the first spring 35.

[0081] In the embodiment, the first spring 35 is a coil spring 350 arranged in the compressed state, and the lead screw 2 passes through the interior of the first spring 35. In the coil spring 350, a first end portion 351 on the second nut portion 32 side is adjacent to the second nut portion 32, and a second end portion 352 on the first nut portion 31 side is adjacent to the second support plate portion 617. Accordingly, the second nut portion 32 is biased toward the first plate portion 41 (a direction spaced from the first nut portion 31) in the direction of the axis L.

[0082] Thus, it is possible to suppress rattle between the external threads of the lead screw 2 and the internal threads of the nut portion 3 (the first nut portion 31 and the second nut portion 32). Furthermore, in the embodiment, the first nut portion 31 provided on the opposite side to the motor 1 and the first plate portion 41 between the first nut portion 31 and the second nut portion 32 are not relatively movable with respect to the slider 61 of the movable member 6. Therefore, when the driven member is mounted on the movable member 6, the driven member is mounted at a position biased to the side opposite to the motor 1 and the first plate portion 41.Therefore, when the movable member 6 is driven in a direction approaching the motor 1 and the first plate portion 41, it is difficult for the driven member to interfere with the motor 1, the first plate portion 41, and the elements arranged around the motor 1 and the first plate portion 41. Thus, even with the reduction of rattling by the two nut portions 3, it is possible to expand a movable range of the movable member 6.

[0083] Furthermore, in the embodiment, when the driven member is mounted on the mounting portion 60, the driven member applies a load to the motor 1 side in the mounting portion 60. Furthermore, the first spring 35 biases the second nut portion 32 toward the motor 1. With this configuration, the embodiment adopts a structure in which the first nut portion 31, provided on the side opposite the motor 1 and the first plate portion 41, is not relatively movable with respect to the slider 61 of the movable member 6. Therefore, even when the movable member 6 is driven toward the motor 1 side, the load of the driven member is applied in a direction to reduce a biasing force of the first spring 35, and thus a thrust of the motor 1 can be small.Thus, a thrust difference required for the engine 1 can be reduced when the movable element 6 is driven to the side of the engine 1 and when the movable element 6 is driven to the side opposite to the engine 1.

[0084] The marks 315 and 325, which align the angular positions of the first nut portion 31 and the second nut portion 32, are provided in the first nut portion 31 and the second nut portion 32, respectively. In this embodiment, the marks 315 and 325 are protruding ridge portions extending in the axis L direction on a surface facing the third plate portion 43 in the first nut portion 31 and the second nut portion 32. According to such a configuration, the angular positions of the first nut portion 31 and the second nut portion 32 can be accurately aligned with the marks 315 and 325. Therefore, even if the pitch of the external threads of the lead screw 2 (the pitch of the internal threads of the nut portion 3) is increased, the first nut portion 31 and the second nut portion 32 can be arranged in an appropriate phase with respect to the lead screw 2.In addition, since the marks 315 and 325 are protruding ridge portions extending in the direction of the axis L, it is easy to visually confirm the marks 315 and 325 and suppress the occurrence of a misassembly situation. (Detailed configuration of the nut mechanism 30 or the like)

[0085] Fig. 15 is a perspective exploded view of the nut mechanism 30 shown in Fig. 2 is shown. Fig. 16 is a cross-sectional view of the Fig. 2 shown nut mechanism 30. As shown in the Fig. 15 and Fig. 16, the first nut portion 31 and the second nut portion 32 each include cylindrical portions 311 and 321 in which internal threads engaging with the lead screw 2 are formed on an inner peripheral surface, and angle flange portions 312 and 322 formed at the end portions of the cylindrical portions 311 and 321 on the side opposite to the coil spring 350.

[0086] Here, in the second nut portion 32, a groove-like concave portion 320 is formed on a surface of the flange portion 322 on the coil spring 350 side, in which the first end portion 351 of the coil spring 350 on the second nut portion 32 side is received. In this embodiment, the flange portion 322 is polygonal when viewed in the axis L direction, and a protruding portion 323 protruding from the flange portion 322 in the axis L direction is formed around the cylindrical portion 321 at each corner portion. Therefore, a groove-like concave portion 320 in an arc shape when viewed in the axis L direction is formed between the cylindrical portion 321 and the protruding portion 323 at each corner portion of the flange portion 322. In the embodiment, the groove-like concave portion 320 has a depth equal to or greater than 1 / 2 of a diameter of a wire member constituting the coil spring 350. In the Fig. In the example shown in Figure 16, the depth of the groove-like concave portion 320 is substantially equal to the diameter of the wire material constituting the coil spring 350. In the embodiment, the first nut portion 31 and the second nut portion 32 are formed by attaching the nut portions 3 having the same configuration in opposite directions along the axis L.

[0087] According to such a configuration, it is possible to prevent the first end portion 351 of the coil spring 350 from detaching from the second nut portion 32. Here, the flange portion 322 is a quadrilateral as viewed in the axis L direction, and a groove-like concave portion 320 is formed in each of the four corner portions. Thus, by utilizing the protrusions 323 provided at the corner portions, it is possible to miniaturize the second nut portion 32 even though the groove-like concave portion 320 is formed.

[0088] The groove-like concave portions 320 may not be provided at all corners, as long as the groove-like concave portions 320 are provided at a plurality of locations spaced apart from each other in the circumferential direction. However, from the perspective of adequately supporting the first end portion 351 of the coil spring 350, it is preferable that the groove-like concave portions 320 be provided at least at two diagonally located corner portions or at two locations widely spaced apart from each other in the circumferential direction. Furthermore, the groove-like concave portion 320 may be provided over the entire circumference.

[0089] In this embodiment, the opening portion 617a disposed in the second support plate portion 617 between the coil spring 350 and the first nut portion 31 among the three plate portions is, in accordance with the above configuration of the nut portion 3, a notch directed toward an open end 617b in the direction orthogonal to the direction of the axis L, and a cylindrical portion 311 of the first nut portion 31 is located inside the notch, as shown in Fig. 10 shown.

[0090] Here, an inner peripheral surface 617c of the notch-like opening portion 617a on the side opposite to the open end 617b side is a circular arc-shaped surface bent along the outer peripheral surface of the cylindrical portion 311 of the first nut portion 31 and abutting against the cylindrical portion 311 of the first nut portion 31. Therefore, even if the second end portion 352 of the coil spring 350 is supported by the second support plate portion 617 of the movable member 6, the second end portion 352 of the coil spring 350 can be supported by the movable member 6 over a wide range in the circumferential direction.

[0091] In this embodiment, the opening portions 616a and 618a formed in the first support plate portion 616 and the third support plate portion 618 are also notches directed toward the open ends 616b and 618b in the direction orthogonal to the axis L direction. The open ends 616b, 617b, and 618b are all directed in the same direction, and in this embodiment, the open ends 616b, 617b, and 618b are directed toward the side where the third plate portion 43 is located. (Support structure for the guide shaft 5)

[0092] Fig. 17 is an illustrative view showing a fixing structure of the guide shaft 5 in the linear drive device 100 in Fig. 1 illustrates, and Fig. 17 shows a method for attaching the guide shaft 5 to the second plate section 42. As shown in the Fig. 1 and Fig. As shown in Figure 2, in the bracket 4, a first shaft hole 415 into which the guide shaft 5 is inserted is formed in the first plate portion 41, and a second shaft hole 425 into which the guide shaft 5 is inserted is formed in the second plate portion 42. Therefore, when the guide shaft 5 is provided, the guide shaft 5 is inserted into the first shaft hole 415 and the second shaft hole 425 along the axis L of the lead screw 2. At this time, the guide shaft 5 is pressed into one of the first shaft hole 415 and the second shaft hole 425, and an inner diameter of the other shaft hole is larger than an outer diameter of the guide shaft 5. In this embodiment, the guide shaft 5 is pressed into the first shaft hole 415 between the first shaft hole 415 and the second shaft hole 425, and an inner diameter of the second shaft hole 425 is larger than an outer diameter of the guide shaft 5.

[0093] Here, in the guide shaft 5, one circumferential portion 5a abuts the inner circumferential surface of the second shaft hole 425, and the other circumferential portion abuts a partially overhanging portion 425c on the inner circumferential surface of the second shaft hole 425 (a portion indicated by an alternating long and short dash line). In the embodiment, in the outer circumferential surface of the guide shaft 5, the circumferential portion 5a on the lower side where the third plate portion 43 is located abuts a portion 425a where the third plate portion 43 is located on the inner circumferential surface of the second shaft hole 425, and the guide shaft 5 and a partially overhanging portion 425c on the inner circumferential surface of the second shaft hole 425 abut each other at two locations 425b in the circumferential direction located on the opposite side to the third plate portion 43.

[0094] Since the guide shaft 5 is therefore arranged with respect to a position at which a circumferential portion of the guide shaft 5 abuts the inner circumferential surface of the second shaft hole 425, it is possible to provide the guide shaft 5 at a suitable position if a position at which a circumferential portion of the guide shaft 5 abuts the inner circumferential surface of the second shaft hole 425 is formed precisely with respect to the first shaft hole 415. For example, it is possible to improve the parallelism accuracy between the lead screw 2 and the guide shaft 5. In particular, in the embodiment with the overhanging portion 425c, the guide shaft 5 is fixed in the second shaft hole 425 in which an edge of the second shaft hole 425 is in contact with the two positions 425b on both sides with the virtual plane P interposed therebetween, as shown in Fig. 9, is plastically deformed and formed by a caulking process in which the inner peripheral surface of the second shaft hole 425 is brought close to the guide shaft 5. Therefore, the guide shaft 5 is pressed in a downward direction as indicated by an arrow S after caulking. According to FIG. 5, the guide shaft 5 can be brought close to the side where the lead screw 2 is located, and a portion (portion 5a) located immediately below the guide shaft 5 can abut against the portion 425a located immediately below the second shaft hole 425. Such a configuration can be applied to a case where the guide shaft 5 is pressed into the second shaft hole 425 and an inner diameter of the first shaft hole 415 is larger than an outer diameter of the guide shaft 5.

[0095] In this embodiment, since the guide shaft 5 is supported with respect to the first plate portion 41 and the second plate portion 42 of the bracket 4, and the lead screw 2 is supported with respect to the second plate portion 42 of the bracket 4, ribs 44 for reinforcement are provided on the inner side of a bent portion between the first plate portion 41 and the third plate portion 43 and the inner side of a bent portion between the second plate portion 42 and the third plate portion 43, as shown in Figures 1 and 2, so that the strength of the bent portion of the first plate portion 41 and the second plate portion 42 with respect to the third plate portion 43 can be improved and the oblique inclination is suppressed. In this embodiment, the ribs 44 are formed by spin working. [Method for manufacturing a linear drive device 100]

[0096] Fig. 18 is an illustrative view illustrating a method of manufacturing a linear drive device 100 to which the present invention is applied, and illustrates a process of attaching the nut mechanism 30 to the movable member 6. In a step of manufacturing a linear drive device 100 according to this embodiment, in a step of attaching the nut mechanism 30 to the movable member 6, the lead screw 2 is guided by the first nut portion 31, the coil spring 350, and the second nut portion 32, as shown in Fig. 18. In this case, a device 200 having a thickness equal to or slightly greater than that of the second support plate portion 617 of the movable member 6 is clamped between the first nut portion 31 and the coil spring 350. Here, the device 200 is movable in a direction orthogonal to the axis L of the lead screw 2.

[0097] The device 200 is a plate-like member having a notch 201, one end of which is an open end 202. In the notch 201, an inner peripheral surface on the side opposite the open end 202 is a circular arc-shaped surface 204 that is bent along the cylindrical portion 311 of the first nut portion 31 and abuts against the cylindrical portion 311 of the first nut portion 31. When the device 200 is slid with the open end 202 toward the first nut portion 31, the device 200 is sandwiched between the flange portion 312 of the first nut portion 31 and the coil spring 350, and the flange portion 312 and the coil spring 350 are held at a space that allows the second support plate portion 617 to be inserted.Since a distal end portion of the device 200 is an inclined surface 203 in which the side in which the flange portion 312 is located is sharp, the device 200 is easily inserted between the flange portion 312 of the first nut portion 31 and the coil spring 350.

[0098] Next, when the movable member 6 is caused to approach the side where the first nut portion 31 is located from the direction orthogonal to the axis L direction, the device 200 is pushed in the direction orthogonal to the axis L direction by the second support plate portion 617, and therefore, the lead screw 2 is detached from the notch 201 through the open end 202 and inserted into the inside of the opening portion 617a through the open end 617b. Thereby, the second support plate portion 617 is inserted between the flange portion 312 of the first nut portion 31 and the coil spring 350. Thus, it is possible to efficiently assemble the nut mechanism 30 into the movable member 6. [Modification example of the present invention]

[0099] Fig. 19(a) and Fig. 19(b) are perspective views of the nut portion 3 used for the linear drive device 100 according to a modification example of the present invention, Fig. 19(a) is a perspective view of the nut portion 3 according to a first modification example, and Fig. 19(b) is a perspective view of a nut portion according to a second modification example. Fig. 20(a) and Fig. 20(b) are illustrative views schematically showing a state in which the Fig. 19(a) and Fig. 19(b) is rotated around the axis L of the lead screw 2, Fig. 20(a) is a cross-sectional view of the main portions illustrating an abutting state of the nut portion 3 and the inner wall of the nut receiving portion 6a when the nut portion 3 has rotated clockwise, and Fig. 20(b) is a cross-sectional view of the main portions illustrating an abutting state of the nut portion 3 and the inner wall of the nut receiving portion 6a when the nut portion 3 has rotated counterclockwise. Fig. 21(a) and Fig. 21(b) are illustrative views schematically showing a state in which the nut portion 3 is rotated about the axis L of the lead screw 2, in a case where the Fig. 19(a) and Fig. 19(b) projection 3b is not present. Fig. 21(a) is a cross-sectional view of the main portions showing an abutting state of the nut portion 3 and the inner wall of the nut receiving portion 6a when the nut portion 3 rotates clockwise, and Fig. 21(b) is a cross-sectional view of the main portions illustrating an abutting state of the nut portion 3 and the inner wall of the nut receiving portion 6a when the nut portion 3 rotates counterclockwise. Fig. 22 is a front view when the bracket is removed in the linear drive device 100 according to the modification example of the present invention.

[0100] In Fig. 19(a) and Fig. 19(b), in at least one of the two nut portions 3 used for the linear drive device of the embodiment, the projections 3b (three-dimensional convex curved surfaces) each having a substantially hemispherical shape are formed at both end portions in the rotational direction on two rectangular surfaces 3a which are aligned with respect to the axis of the nut portion 3, the center portions being in the direction of the axis L, so that the projections 3b are symmetrical with the axis L, as shown in Fig. 19(a). In this embodiment, the projections 3b are formed in both the first nut portion 31 and the second nut portion 32.

[0101] Here, the projection 3b is formed with position and height dimensions such that the projection 3b abuts against the inner wall 6e of the nut receiving portion 6a earlier than a corner portion 3e of the outer peripheral surface of the nut portion 3 when the nut portion 3 rotates about the axis L of the lead screw 2, as shown in Fig. 20(a). That is, the protrusions 3b are provided with a height dimension that allows an outer surface to come into point contact with the inner wall 6e of the nut receiving portion 6a at both end portions in the rotational direction on the rectangular surfaces 3a of the outer peripheral surface of the nut portion 3 (a wall surface) of the nut receiving portion 6a facing the inner wall 6e when the nut portion 3 rotates about the axis L of the lead screw 2 and abuts against the inner wall 6e earlier than a corner portion 3e of the outer peripheral surface at the time of rotation of the nut portion 3. Therefore, even if a gap is formed between the nut receiving portion 6a and the nut portion 3, the protrusion 3b of the nut portion 3 abuts against the inner wall 6e of the nut receiving portion 6a when the engine 1 is started and stopped.This makes it possible to prevent or greatly suppress the generation of abnormal noise generated between the nut portion 3 and the movable member 6.

[0102] In particular, since the projections 3b are formed at the symmetrical positions with the axis of the nut portion 3 (the axis L of the lead screw 2), the projection 3b located on the side opposite to the L axis can be balanced against the inner wall 6e of the nut receiving part 6a when starting and stopping the motor 1.

[0103] In the Fig. 20(b), projections 3b having substantially hemispherical shapes are formed in both end portions in the rotation direction on the two rectangular surfaces 3a facing the axis line of the nut portion 3 (axis L of the lead screw 2), which are both end portions in the direction of axis L. Such projections 3b are also formed with position and height dimensions that enable the projections 3b to be brought into contact with the outer peripheral surface of the nut portion 3 earlier than the corner portion 3e upon rotation of the nut portion 3 at the The inner wall 6e of the nut receiving portion 6a is adjacent to the inner wall 6e. This makes it possible to achieve the same operation and effect in the linear drive device as the nut portion 3 was used in.

[0104] On the other hand, as in Fig. 21(a) and Fig. 21(b), when the projection 3b is not provided, the corner portion 3e of the outer peripheral surface of the nut portion 3 abuts against the inner wall 6e of the nut receiving portion 6a, so that abnormal noise is liable to be generated.

[0105] The one with reference to the Fig. 19 and Fig. 20 can be applied, for example, to the linear drive device 100 using the method described with reference to Fig. 8(a) and Fig. 8(b) described second spring 11 can be applied as in Fig. 22. Note that in the embodiment, only the case where the nut portions 3 each having a square outer shape was used was described, but the present invention is not limited to this, and it is possible to achieve the same operation and effect even by using other nut portions having an n-angle shape such as a hexagon. [Other embodiments]

[0106] Although the first nut portion 31 and the second nut portion 32 are configured separately from the movable member 6 in the above embodiment, the first nut portion 31 may be configured integrally with the movable member 6. Although the first spring 35 is the coil spring in the above embodiment, a leaf spring may be used for the first spring 35. (Industrial applicability)

[0107] In the present invention, since the movable member is driven via the guide shaft and the lead screw supported by the bracket, it is difficult for chatter to occur when driving the movable member. Furthermore, by employing the nut mechanism in which the first spring is interposed between the two nut portions (the first nut portion and the second nut portion), it is possible to suppress chatter of the nut portions with respect to the lead screw. Since the first nut portion on the side opposite to the motor and the first plate portion along the two nut portions are not relatively movable with respect to the slider, the driven member is mounted at a position biased toward the motor and the side opposite to the first plate portion when the driven member is mounted on the movable member.Therefore, when the movable element is driven in a direction closer to the motor and the first plate portion, it is difficult for the driven elements to interfere with the motor, the first plate portion, and the elements arranged around the motor and the first plate portion. Thus, even while reducing rattle, the movable range of the movable element can be expanded, making it possible to reduce rattle accordingly.

Claims

[1] Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating about an axis integral with an output shaft (7) of the motor; a nut mechanism (30) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut mechanism (30); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein the nut mechanism (30) includes a first nut portion (31) that is not relatively movable in an axial direction of the lead screw (2) with respect to the movable element (6), a second nut portion (32) that is relatively movable in the axial direction with respect to the movable element (6) toward the first plate portion (41) side of the first nut portion (31), and a first spring (35) that biases the second nut portion (32) in the axial direction, wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [2] A linear drive device (100) according to claim 1, wherein the lead screw (2) and the guide shaft (5) are arranged at positions overlapping in a vertical direction. [3] Linear drive device (100) according to claim 2, wherein a mounting portion (60) of a driven element is provided in the movable element (6), and a center of the mounting portion (60) overlaps the lead screw (2) and the guide shaft (5) in a vertical direction. [4] A linear drive device (100) according to claim 3, wherein the movable member (6) is formed with plane symmetry with respect to a virtual plane defined by a center axis of the lead screw (2) and a center axis of the guide shaft (5). [5] Linear drive device (100) according to any one of claims 1 to 4, wherein a switch (18) suitable for detecting the movable element (6) is held in the holder (4). [6] Linear drive device (100) according to claim 5, wherein the switch (18) is held in the first plate portion (41). [7] Linear drive device (100) according to claim 6, wherein a fourth plate portion (410) bent toward the second plate portion (42) is provided at an end portion of the first plate portion (41) on the side opposite the third plate portion (43), and the switch (18) is held in the fourth plate section (410). [8] A linear drive device according to claim 7, wherein the fourth plate portion (410) is parallel to the third plate portion (43). [9] The linear drive device (100) according to any one of claims 6 to 8, wherein the switch (18) is a contact switch (18a) that detects the movable member (6) according to the contact with the movable member (6). [10] A linear drive device (100) according to claim 9, wherein a plate portion (619) projecting to the side opposite to the third plate portion (43) and capable of coming into contact with the switch (18) is provided in the movable member (6). [11] Linear drive device (100) according to any one of claims 1 to 4, wherein the first spring (35) is a helical spring and wherein the lead screw (2) extends through the helical spring, the second nut portion (32) includes a cylindrical portion (321) having internal threads formed on an inner peripheral surface, the internal threads meshing with a lead screw (2), and a rectangular flange portion (322) formed at an end portion of the cylindrical portion (321) on the side opposite the coil spring, and the flange portion (322) receives a first end portion of the first spring (35). [12] The linear drive device (100) according to claim 11, wherein in the second nut portion (32), a groove-like concave portion (320) in which the first end portion is received is formed on a surface of the flange portion (322) on the coil spring side. [13] The linear drive device (100) according to claim 12, wherein the groove-like concave portion (320) has a depth equal to or greater than 1 / 2 a diameter of a wire material constituting the coil spring. [14] The linear drive device (100) according to claim 12 or 13, wherein the groove-like concave portion (320) is formed between the cylindrical portion (321) and a projection (3b) projecting from the flange portion (322) toward the coil spring side. [15] Linear drive device (100) according to any one of claims 1 to 4, wherein the first spring (35) is a helical spring and wherein the lead screw (2) extends through the helical spring, the first nut portion (31) includes a cylindrical portion (311) having internal threads formed on an inner peripheral surface, the internal threads engaging with the lead screw (2), and a rectangular flange portion (312) formed at an end portion of the cylindrical portion on the side opposite the coil spring, the movable element (6) includes a support plate portion (616, 617, 618) which is arranged between the coil spring and the flange of the first nut portion (31) and against which a second end portion of the coil spring on the side of the first nut portion (31) and a surface of the first nut portion (31) on the coil spring side of the flange bear, a notch-like opening portion (616a, 617a, and 618a) directed toward an open end in a direction perpendicular to the axial direction is formed in the support plate portion (616, 617, 618), the cylindrical portion (311) of the first nut portion (31) is located on an inner side of the opening portion (616a, 617a, and 618a), and an inner peripheral surface located on the side opposite to the open end side of the opening portion (616a, 617a, and 618a) is a circular arc-shaped surface bent along an outer peripheral surface of the cylindrical portion (311) of the first nut portion (31) and abutting against the cylindrical portion (311) of the first nut portion (31). [16] The linear drive device (100) according to claim 15, wherein a mark (315, 325) aligning an angular position of the first nut portion (31) and the second nut portion (32) is provided in each of the first nut portion (31) and the second nut portion (32). [17] The linear drive device (100) according to claim 16, wherein the mark (315, 325) is located on the side toward which the open end of each of the first nut portion (31) and the second nut portion (32) is directed. [18] A linear drive device (100) according to claim 16 or 17, wherein the mark (315, 325) is a protruding rib. [19] Linear drive device (100) according to any one of claims 1 to 4, wherein a first shaft hole (415) is formed in the first plate portion (41), into which the guide shaft (5) is fitted, a second shaft hole (425) is formed in the second plate section (42), into which the guide shaft (5) is fitted, wherein the guide shaft (5) is pressed into one of the first shaft hole (415) and the second shaft hole (425), wherein an inner diameter of the other shaft hole is larger than an outer diameter of the guide shaft (5), and a circumferential portion of the guide shaft (5) abuts an inner circumferential surface of the other shaft hole and another circumferential portion abuts a partially overhanging portion of the inner circumferential surface of the other shaft hole. [20] Linear drive device (100) according to claim 19, wherein the peripheral portion abuts against an inner peripheral surface of the other shaft hole on the side of the lead screw (2) in a circumferential direction of the guide shaft (5), and the other circumferential section rests against the partially overhanging section formed by caulking on the side opposite the lead screw (2) in the circumferential direction of the guide shaft (5). [21] Linear drive device (100) according to any one of claims 1 to 4, wherein the third plate portion (43) extends parallel to the guide axis, and the movable member (6) includes a pair of buffer arm portions (13) having flexibility projecting to opposite sides, with the lead screw (2) interposed therebetween to face the third plate portion (43), and a leg portion (14) bent from a distal end of each of the pair of buffer arm portions (13) toward the third plate portion (43) and abutting against the third plate portion (43). [22] A linear drive device (100) according to claim 1 or 2, wherein in at least one nut portion (31, 32) of the first nut portion (31) and the second nut portion (32), a projection (3b) is provided which projects further toward the movable member (6) than a corner of an outer peripheral surface of the nut portion (31, 32). [23] Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating about an axis integral with an output shaft (7) of the motor (1); a nut portion (31, 32) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut portion (31, 32); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein the lead screw (2) and the guide shaft (5) are arranged at positions that overlap in a vertical direction, wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [24] Linear drive device (100) according to claim 23, wherein a mounting portion (60) of a driven element is provided in the movable element (6), and a center of the mounting portion (60) overlaps the lead screw (2) and the guide shaft (5) in a vertical direction. [25] A linear drive device (100) according to claim 24, wherein the movable element (6) is formed with plane symmetry with respect to a virtual plane defined by a center axis of the lead screw (2) and a center axis of the guide shaft (5). [26] Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating about an axis integral with an output shaft (7) of the motor (1); a nut portion (31, 32) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut portion (31, 32); and a bracket (4) including a first plate portion (41) fixed to an output-side end face of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein a switch (18) capable of detecting a movable element (6) is held in the bracket (4), wherein in the output shaft (7), an output-side opposite end portion (7a) located on the side opposite the bracket (4) protrudes from an output-side opposite end face (8a),which is located on the side opposite the support (4) of the housing (8), wherein the linear drive device (100), characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [27] Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating around an axis integral with an output shaft (7) of the motor (1); a nut mechanism (30) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut mechanism (30); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein the nut mechanism (30) includes a first nut portion (31) which is not relatively movable in an axial direction of the lead screw (2) with respect to the movable element (6), a second nut portion (32) which is relatively movable in the axial direction with respect to the movable element (6), and a first spring (35) which preloads the second nut portion (32) in the axial direction, wherein the first spring (35) is a helical spring in which the lead screw (2) passes through an inner side thereof, the second nut portion (32) includes a cylindrical portion (321) with internal threads formed on an inner circumferential surface, the internal threads meshing with the lead screw (2), and a rectangular flange portion (322) formed at an end portion of the cylindrical portion (321) on the side opposite the coil spring, and the flange portion (322) receives a first end portion of the first spring (35), wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [28] The linear drive device (100) according to claim 27, wherein in the second nut portion (32), a groove-like concave portion (320) in which the first end portion is received is formed on a surface of the flange portion (322) on the coil spring side. [29] Linear drive device (100) comprising: an engine (1); a lead screw (2) rotating about an axis integral with an output shaft (7) of the motor (1); a nut mechanism (30) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut portion (30); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein the nut mechanism (30) includes a first nut portion (31) which is not relatively movable in an axial direction of the lead screw (2) with respect to the movable element (6), a second nut portion (32) which is relatively movable in the axial direction with respect to the movable element (6), and a first spring (35) which biases the second nut portion (32) in the axial direction, wherein the first spring (35) is a helical spring in which the lead screw (2) passes through an inner side thereof, the first nut portion (31) includes a cylindrical portion (311) having internal threads formed on an inner peripheral surface, the internal threads meshing with the lead screw (2), and a rectangular flange portion (312) formed at an end portion of the cylindrical portion (311) on the side opposite the coil spring, the movable element (6) includes a support plate portion (616, 617, 618) which is arranged between the coil spring and the flange of the first nut portion (31) and against which a second end portion of the coil spring on the side of the first nut portion (31) and a surface of the first nut portion (31) on the side of the coil spring of the flange bear, a notch-like opening portion (616a, 617a, and 618a) directed toward an open end in a direction perpendicular to the axial direction is formed in the support plate portion (616, 617, 618), the cylindrical portion (311) of the first nut portion (31) is located on an inner side of the opening portion (616a, 617a, and 618a), and an inner peripheral surface located on the side opposite the open end side of the opening portion (616a, 617a, and 618a) is a circular arc-shaped surface bent along an outer peripheral surface of the cylindrical portion (311) of the first nut portion (31) and abutting against the cylindrical portion (311) of the first nut portion (31), wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [30] Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating around an axis integral with an output shaft (7) of the motor (1); a nut mechanism (30) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut portion (30); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein the nut mechanism (30) includes a first nut portion (31) which is not relatively movable in an axial direction of the lead screw (2) with respect to the movable member (6), a second nut portion (32) which is relatively movable in the axial direction with respect to the movable member (6), and a first spring (35) which biases the second nut portion (32) in the axial direction, and a mark (315, 325) aligning an angular position of the first nut portion (31) and the second nut portion (32) is provided on both the first nut portion (31) and the second nut portion (32), wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [31] Linear drive device (100), comprising: an engine (1); a lead screw (2) rotating around an axis integral with an output shaft (7) of the motor (1); a nut portion (31, 32) forming a feed screw mechanism together with the lead screw (2); a guide shaft (5) extending parallel to the lead screw (2); a movable member (6) movably supported by the guide shaft (5) and driven in an axial direction of the lead screw (2) by the motor (1) via the nut portion (31, 32); and a bracket (4) including a first plate portion (41) fixed to an output-side end surface of a housing (8) of the motor (1) located on the lead screw (2) side, a second plate portion (42) facing the first plate portion (41) on a distal end side of the lead screw (2), and a third plate portion (43) connecting the first plate portion (41) to the second plate portion (42), and a bearing (10) rotatably supporting the distal end side of the lead screw (2) held on the second plate portion (42), wherein a first shaft hole (415) is formed in the first plate portion (41) into which the guide shaft (5) is fitted, a second shaft hole (425) into which the guide shaft (5) is fitted is formed in the second plate portion (42), the guide shaft (5) is pressed into a shaft hole of the first shaft hole (415) and the second shaft hole (425), wherein an inner diameter of the other shaft hole is larger than an outer diameter of the guide shaft (5), and a circumferential portion of the guide shaft (5) abuts against an inner circumferential surface of the other shaft hole and another circumferential portion abuts against a partially overhanging portion of the inner circumferential surface of the other shaft hole, wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [32] Linear drive device (100), comprising: an engine (1); a lead screw (2) formed coaxially integral with an output shaft (7) of the motor (1); a nut that engages with the lead screw (2); a guide shaft (5) arranged parallel to and at a distance from the lead screw (2); a movable element (6) which is movably provided on the guide shaft (5) and to which the nut is non-rotatably attached; and a flat plate-like bracket (4) having two end portions and being fixed at one end portion to a housing (8) of the motor with a plate surface extending parallel to the lead screw (2), and the other end portion to which a bearing (10) rotatably supporting one end portion of the lead screw (2) is attached, wherein a buffer arm portion (13) extending parallel to the plate surface of the bracket (4) in a direction orthogonal to the axial direction or extending in a direction in which the buffer arm portion (13) is gradually spaced from the plate surface toward a distal end and projects toward the outside of the bracket (4), and a leg portion (14) bent toward the plate surface side of the bracket (4) from the distal end of the buffer arm portion (13) and having a distal end portion abutting against the plate surface of the bracket (4) are integrally formed in both side portions of the movable member (6) in the axial direction of the lead screw (2), wherein one end of the output shaft (7) is inserted through a bearing (9) provided on one end surface of the housing (8), and one end surface thereof projects from the one end surface and is supported to be rotatable, and a second spring (11, 12) in the shape of a flat,curved plate which presses the output shaft (7) in an axial direction is provided on an end face of the housing (8), one end surface of the output shaft (7) is formed by a flat surface or a spherical surface, wherein the linear drive device (100) characterized by is that it also includes: the second spring (11, 12) is formed with a fixing portion formed in one end portion and fixed to one end surface of the housing (8), a biasing portion (12a) formed by bending into a convex circular arc shape in the axial direction, and a pressing portion (12b) formed by bending into an inverse circular arc shape from the other end portion of the biasing portion (12a), and an outer peripheral surface of the pressing portion (12b) abuts against the one end surface of the output shaft (7). [33] The linear drive device (100) according to claim 32, wherein a portion of the plate surface of the bracket (4) in a region of abutment against a distal end of the leg portion (14) is formed to protrude toward the leg portion (14) by a half-stamping process. [34] Linear drive device (100), comprising: a lead screw (2) rotated and driven by a motor (1); an n-polygonal nut, of which an outer peripheral surface screwed to the lead screw (2) is formed as n square surfaces; a guide shaft (5) arranged parallel to and at a distance from the lead screw (2); and a sliding plate arranged on and movable on the guide shaft (5) and having a nut receiving portion formed therein in which the nut is inserted and rotation of the nut is blocked by an inner wall; wherein a projection (3b), an outer surface of which is formed as a three-dimensional convex curved surface which comes into point contact with the inner wall of the nut receiving portion and which abuts against the inner wall at the time of rotation of the nut, is provided on a square surface of at least one of the outer peripheral surfaces of the nut facing the inner wall of the nut receiving portion, wherein in the output shaft (7), an end portion (7a) opposite the output side, which is located on the side opposite the bracket (4), protrudes from an end surface (8a) opposite the output side, which is located on the side opposite the bracket (4) of the housing (8), wherein the linear drive device (100) characterized by is that it also includes: a second spring (11, 12) in the form of a curved plate which presses the end portion (7a) of the output shaft (7) opposite the output side in the direction of the output side on which the bracket (4) is located, to which the end surface (8a) opposite the output side is attached, the end portion (7a) opposite the output side is formed by a flat surface or a spherical surface, and the second spring (11, 12) includes a fixing portion fixed to the end surface (a) of the housing (8) opposite the output side, a biasing portion (12a) bent to be spaced from the output shaft (7) and extending from the fixing portion (12c) to the side in which the end portion (7a) opposite the output side is located, and a pressing portion (12b) extending in a direction in which the pressing portion (12b) is spaced from the end portion (7a) opposite the output side, while being bent in a direction opposite to the biasing portion (12a) to be adjacent to the end portion (7a) opposite the output side from the biasing portion (12a). [35] A linear drive device (100) according to claim 34, wherein the nut is formed with a square outer shape, and the projections (3b) are formed at both end portions in the rotational direction on the two square surfaces facing each other with respect to the axis of the nut.

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