Direct-acting telescopic mechanism

Abstract

The purpose of this application is to provide a linear telescopic mechanism that can ensure high rigidity in all directions of three orthogonal axes and has no limitation on the setting posture. The linear telescopic mechanism (1) of this embodiment includes: a block column (30) formed by connecting multiple blocks (40) along the connection direction, a housing part (10) for housing the block column, a pulling mechanism for feeding and feeding the block column along the connection direction, and a fixing mechanism (20) for fixing the relative position of the front end position (Pc) of the block column fed from the housing part with respect to the entry / exit position (Pe) on the housing part of the block column in two directions orthogonal to the connection direction of the block column.

Description

Technical Field

[0001] This application relates to a linear telescopic mechanism. Background Technology

[0002] Since linear telescopic mechanisms do not require an elbow joint, they offer high safety and are expected to be applied to collaborative robots. As a linear telescopic mechanism, a structure for extending and retracting a block array composed of multiple connected blocks was investigated (see Patent Documents 1, 2, and 3).

[0003] To assemble the linear telescopic mechanism onto the robot, high rigidity must be ensured in all directions of the three orthogonal axes. Besides flexing in all directions (up, down, left, and right), torsional and forward / backward sway must be minimized, while simultaneously reducing the deviation between the actual position and the controlled position of the arm's tip. Furthermore, depending on its application, the robot arm may not only be vertically mounted on the ground but also horizontally mounted on a wall or suspended from the ceiling, requiring it to operate normally in any of these various configurations.

[0004] Existing technical documents

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5435679

[0007] Patent Document 2: Japanese Patent Application Publication No. 2015-213974

[0008] Patent Document 2: Japanese Patent Application Publication No. 62-148186 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The goal is to develop a linear telescopic mechanism that ensures high rigidity and improves positional accuracy in all directions along three orthogonal axes, while offering unrestricted orientation.

[0011] means for solving problems

[0012] One aspect of the direct-acting telescopic mechanism disclosed herein includes: a block array, formed by connecting multiple blocks along a connecting direction; a housing portion for housing the block array; a conveying mechanism for feeding and pulling the block array in along the connecting direction; a limiting structure for limiting the entry and exit positions of the block array on the housing portion in two directions orthogonal to the connecting direction of the block array; and a fixing mechanism for fixing the relative position of the front end of the block array fed from the housing portion relative to the entry and exit positions in two directions.

[0013] Effects of the Invention

[0014] Based on this design, a linear telescopic mechanism is provided that can ensure high rigidity and improve positional accuracy in all directions of the three orthogonal axes, and has no restrictions on the setting posture. Attached Figure Description

[0015] Figure 1 This is a perspective view of the direct-acting telescopic mechanism during contraction in one embodiment.

[0016] Figure 2 It is a three-dimensional diagram of the linear telescopic mechanism during extension.

[0017] Figure 3 This is a side view showing the internal structure of the linear telescopic mechanism during retraction, with the arm removed.

[0018] Figure 4 This is a side view showing the internal structure of the linear telescopic mechanism during contraction.

[0019] Figure 5 This is a side view showing the internal structure of the linear telescopic mechanism when it extends.

[0020] Figure 6 yes Figure 4 A three-dimensional view of the front of the block.

[0021] Figure 7 yes Figure 4 The three-dimensional view behind the block in the image.

[0022] Figure 8 yes Figure 4 A side view of the block in the image.

[0023] Figure 9 It shows the... Figure 4 A three-dimensional view of a square tube bracket that restricts the entry and exit positions of the blocks of the direct-acting telescopic mechanism.

[0024] Figure 10 yes Figure 9 A partial enlarged view of .

[0025] Figure 11 yes Figure 10 The main view.

[0026] Figure 12 It is a perspective view showing the shell opening together with the square tube support.

[0027] Figure 13 It is a side view showing the positional relationship between the entry and exit positions of the block column and the front end position during contraction.

[0028] Figure 14 It is a top view showing the positional relationship between the entry and exit positions of the block column and the front end position during contraction.

[0029] Figure 15 It is a side view showing the positional relationship between the entry and exit positions of the block column and the front end position when it is extended.

[0030] Figure 16 It is a top view showing the positional relationship between the entry and exit positions of the block column and the front end position when it is extended.

[0031] Figure 17 This is a front view showing the positional relationship between the centerline of the cylinder and the movement axis of the block column.

[0032] Figure 18 This is a top view showing the direct telescopic mechanism after the telescopic structure has been replaced by multiple direct-acting guide mechanisms connected in series.

[0033] Figure 19 It shows Figure 18 A top view of the elongated linear telescopic mechanism in the middle. Detailed Implementation

[0034] The linear telescopic mechanism of this embodiment will now be described with reference to the accompanying drawings. In the following description, constituent elements having substantially the same function and structure will be given the same reference numerals, and will be described repeatedly only where necessary. The linear telescopic mechanism of this embodiment can be used independently or as a linear telescopic joint of a robot arm mechanism.

[0035] like Figure 1 , Figure 2 As shown, the direct-acting telescopic mechanism 1 has a freely telescopic arm 20 and a housing 10 supporting the arm 20. Typically, the arm 20 is composed of multiple cylinders that rigidly form a telescopic structure (multi-level nested structure), here consisting of four cylinders 21, 22, 23, and 24. Typically, the cylinders 21, 22, 23, and 24 are cylindrical, but they can also be rectangular. Typically, the housing 10 has a hollow quadrangular prism shape. However, the housing 10 is not limited to a quadrangular prism shape, and can also be cylindrical or other shapes.

[0036] The last of the plurality of cylindrical bodies 21, 22, 23, and 24, 24, is fixed to the upper part of the housing portion 10 at its flange in such a manner that the angle between the cylinder centerline C1 and the centerline of the housing portion 10 is maintained at a predetermined angle. Hereinafter, among the three orthogonal axes, the axis parallel to the centerline of the housing portion 10 is used as the Z-axis, the axis parallel to the cylinder centerline C1 is used as the X-axis, and the axis perpendicular to both the X-axis and Z-axis is used as the Y-axis.

[0037] like Figure 3As shown, an opening 13 (hereinafter referred to as shell opening 13) is provided on the upper side wall of the shell portion 10, where the last cylindrical body 24 is fixed. The shell opening 13 communicates the interior of the shell portion 10 with the hollow interior of the cylindrical bodies 21, 22, 23, and 24. The shell opening 13 serves as an entrance / exit for the block array 30, described later, to enter and exit the shell portion 10.

[0038] like Figure 4 , Figure 5 As shown, a block array 30 is inserted into the internal space connecting the interior of the housing 10 to the hollow interiors of the cylindrical bodies 21, 22, 23, and 24. The block array 30 is formed by connecting multiple blocks 40 in a row. The foremost block 40 is connected to the foremost cylindrical body 21. Details will be described later, but the entry and exit positions of the block array 30 relative to the housing 10 are restricted in two directions (YZ) orthogonal to the connection direction (C2) of the block array 30. Furthermore, through a multi-level nested structure, the front end position of the block array 30 exiting from the housing 10 is relatively fixed in these two directions (YZ) relative to the entry and exit positions, thereby enabling the block array 30 to move linearly.

[0039] like Figure 6 , Figure 7 As shown, block 40 has a block body 41. Block body 41 has, for example, a cuboid shape. At the lower front end of block body 41, two forward-protruding bearings 42 and 43 are separately provided in the width direction. At the lower rear end of block body 41, bearings 44 and 46 integrally formed with block body 41 are separately provided in the width direction. The bearings 42 and 43 at the front end of one of two adjacent blocks 40 are embedded between the bearings 44 and 46 at the rear end of the other block 40, and a rotating shaft (not shown) is inserted into a series of holes. Thus, the blocks 40 are rotatably connected in a row. Furthermore, the blocks 40 are connected in a row along a direction orthogonal to the rotating shaft (connection direction).

[0040] like Figure 8 As shown, bearings 42, 43, 44, and 46 are all located on the bottom side of the block body 41, and the block body 41 has a cuboid shape. Therefore, when arranged in a straight line, the end faces of two adjacent blocks 40 abut against each other, thereby restricting further upward rotation but allowing downward rotation. Furthermore, for ease of explanation, a reference line BL is defined as the reference for the blocks 40. The reference line BL is parallel to the length direction (front-back direction) of the block body 41 and passes through the center of the width and height of the block body 41. Moreover, the reference line BL of the blocks 40 arranged in a straight line defines the moving axis C2 of the block column 30.

[0041] Return to Figure 4 , Figure 5The foremost block 40 of the block array 30 is connected to the foremost cylinder 21 among the plurality of cylinders 21, 22, 23, and 24. With the arm 20 retracted, the block array 30 is almost entirely housed inside the housing 10. Inside the housing 10, a drive mechanism is provided to perform the extending and retracting actions of the block array 30. The drive mechanism can be any mechanism such as a rack and pinion mechanism or a ball screw mechanism.

[0042] The basic telescopic action of the direct-acting telescopic mechanism 1 is as follows.

[0043] The drive mechanism delivers the block array 30 housed in the housing portion 10 through the housing opening 13 into the interior of the arm portion 20, thereby moving the foremost block 40 forward. Since the foremost block 40 is connected to the foremost cylindrical body 21, as the foremost block 40 moves forward, other cylindrical bodies 21, 22, and 23 are pulled out one after another from the last cylindrical body 24 fixed in the housing portion 10. As a result, the arm portion 20 extends forward along the cylinder centerline C1.

[0044] The drive mechanism also pulls the block array 30, which is sent out into the interior of the arm 20, back into the interior of the housing 10 through the housing opening 13, thereby moving the foremost block 40 backward. As the foremost block 40 moves backward, it is sequentially retracted into the rear cylinder from the foremost cylinder 21, resulting in the arm 20 retracting backward along the cylinder centerline C1.

[0045] During the telescopic movement of the aforementioned linear telescopic mechanism 1, the up-down and left-right swaying of the block array 30 reduces the positional accuracy of the front end of the arm 20. To ensure the positional accuracy of the front end of the arm 20, the block array 30 needs to move parallel and linearly relative to the cylinder centerline C1.

[0046] To enable the block array 30, which is fed from the interior of the housing section 10 into the interior of the arm section 20 through the housing opening 13, to move linearly along the moving axis C2 parallel to the cylinder centerline C1, the linear telescopic mechanism 1 has a limiting structure 50 that restricts the entry / exit position Pe on the housing section 10 that causes the block array 30 to enter and exit relative to the housing section 10. This entry / exit position Pe is defined as the position where the reference line BL of the block 40 passing through the housing opening 13 intersects with the housing opening surface. The limiting structure 50 restricts this entry / exit position Pe to two directions (YZ) orthogonal to the reference line BL of the blocks 40 arranged in a straight line, i.e., orthogonal to the moving axis C2. The YZ position of the entry / exit position Pe is fixed.

[0047] As a typical example of the limiting structure 50, a bracket 50 (hereinafter referred to as the square tube bracket 50) can be used, which has a square tube shape that matches the shape and outer dimensions of the block 40, thereby allowing the block 40 to pass through with some gaps relative to its four surrounding faces. Figure 9 , Figure 10 As shown, the square tube bracket 50 is fixed at its flange to the periphery of the housing opening 13 of the housing portion 10. Figure 11 , Figure 12 As shown, the square tube bracket 50 is configured such that its inner dimension is equal to or slightly wider than the outer dimension of the block 40 in order to support the outer surface of the block 40 from the top, bottom and left and right directions.

[0048] Based on the square tube support 50 configured as described above, the position of the block 40 passing through the shell opening 13 is restricted in two directions (Y-axis and Z-axis) orthogonal to the cylinder centerline C1 (X-axis), ensuring that the block 40 is always sent out and pulled back from the shell opening 13 in the same manner. At this time, the reference line BL of the block 40 passing through the square tube support 50 always coincides with the moving axis C2. Therefore, the entry / exit position Pe of the block 40 always coincides with the position where the moving axis C2 intersects with the shell opening surface. In other words, the square tube support 50 can restrict the entry / exit position Pe of the block 40 entering and exiting the shell portion 10 in two directions (Y-axis and Z-axis) orthogonal to the cylinder centerline C1 (X-axis).

[0049] In the direct-acting telescopic mechanism 1, the front end position Pc of the block array 30 delivered from the housing 10 is fixed relative to the entry / exit position Pe by a fixing mechanism in two directions (YZ) orthogonal to the cylinder centerline C1. The fixing mechanism consists of multiple cylinders 21, 22, 23, and 24 (arms 20) arranged in a multi-level nested structure. As already explained, the foremost block 40 of the block array 30 is connected to the foremost cylinder 21 of the multiple cylinders 21, 22, 23, and 24. The connection position is positioned such that the front end position Pc of the block array 30 (i.e., the front end position Pc of the foremost block 40) coincides with the moving axis C2, and the connection direction is oriented such that the reference line BL of the block 40 is parallel to the moving axis C2. Furthermore, the front end position Pc of the block array 30 is defined as the position where the front end face of the block body 41 of the foremost block 40 intersects the reference line BL of the block 40.

[0050] Because multiple cylinders 21, 22, 23, and 24 are firmly assembled into a multi-level nested structure, the arm 20 has high rigidity in two directions (Y and Z) orthogonal to the cylinder centerline C1. With the extension / retraction of the block column 30, the front end position Pc of the block column 30 is restricted by the arm 20 in two directions orthogonal to the cylinder centerline C1 (Y-axis and Z-axis directions). Figure 13 , Figure 14 As shown, assuming the coordinates of the entry / exit position Pe of the contracted block column 30 are (X1, Y1, Z1) and the coordinates of the front end position Pc are (X2, Y2, Z2), although X1 is fixed, X2 will change due to the extension and retraction of the arm. That is, X1 and X2 will change relative to each other. On the other hand, the relative position of Y2 with respect to Y1 will not change. Typically, Y2 is always consistent with Y1. Similarly, the relative position of Z2 with respect to Z1 will not change. Typically, Z2 is always consistent with Z1.

[0051] like Figure 15 , Figure 16 As shown, the coordinates of the entry / exit position Pe and the front end position Pc of the block column 30 after the arm 20 extends by ΔL from its retracted state can be represented as follows. That is, the entry / exit position Pe of the block column 30 is unaffected by the extension / extension movement of the arm 20 and remains at the same position (X1, Y1, Z1). On the other hand, since the block column 30 moves forward in a straight line along the movement axis C2, the coordinates of the front end position Pc of the block column 30 can be represented as (X2 + ΔL, Y2, Z2). In the Y-axis and Z-axis directions, the front end position Pc of the block column 30 is relatively fixed relative to the entry / exit position Pe; therefore, the Y and Z coordinates of the front end position Pc do not change due to extension / extension.

[0052] Thus, since the arm 20, which restricts the front end position Pc of the block column 30 in the Y-axis and Z-axis directions, and the square tube bracket 50, which restricts the entry / exit position Pe of the block column 30 on the housing 10 in the Y-axis and Z-axis directions, are fixed relative to the housing 10, the relative position of the front end position Pc of the block column 30 in these two directions relative to the entry / exit position Pe of the block column 30 on the housing 10 is fixed. In other words, the front end position and rear end position of the block column 30, which is fed into the arm 20, are relatively fixed in these two directions. Therefore, the block column 30 always extends in a straight line along the moving axis C2 and always retracts in a straight line. This ensures the accuracy of the front end position of the arm 20. Furthermore, since the entry / exit position Pe and the front end position Pc of the block column 30 are fixed by the restricting structure and the fixing mechanism, the block column 30 is less prone to deflection in the up, down, left, and right directions, thus the orientation when using the linear telescopic mechanism 1 is not restricted. In other words, depending on the application location, the direct-acting telescopic mechanism 1 can not only be installed vertically on the ground, but also horizontally on the wall or suspended from the ceiling. Regardless of which of these installation positions it can be, the direct-acting telescopic mechanism 1 can operate normally.

[0053] Furthermore, according to the direct-acting telescopic mechanism 1 of this embodiment, the rigid blocks 40, arranged in a straight line and with their front and rear end faces abutting each other, firmly bear the external force and load in a direction parallel to the cylinder centerline C1. Additionally, the multiple cylinders 21, 22, 23, and 24, configured in a multi-level nested structure, bear the load in two directions orthogonal to the cylinder centerline C1. Thus, the cylinders 21, 22, 23, and 24, and the block array 30, configured in a multi-level nested structure, distribute the load across all directions of the three orthogonal axes. Therefore, the arm 20 can ensure high rigidity, and in addition to suppressing its vertical and horizontal deflection, it can also minimize torsional and longitudinal swaying.

[0054] In addition, such as Figure 17As shown, the moving axis C2 of the block array 30, which moves linearly, is offset relative to the cylinder centerline C1. That is, the reference line BL (moving axis C2) of the block array 30 passing through the square tube support 50 is not aligned with the cylinder centerline C1 of the cylinders 21, 22, 23, and 24, and the square tube support 50 is installed offset relative to the housing portion 10. Therefore, the block array 30 effectively suppresses the rotation (rotation around the axis) of the cylinders 21, 22, 23, and 24 around the cylinder centerline C1. Furthermore, by offsetting the moving axis C2 downwards relative to the cylinder centerline C1 in the direction of gravity, the downward load always applied to the cylinders 21, 22, 23, and 24 is not only borne by the cylinders themselves but also distributed to the block array 30, thereby further improving the overall rigidity of the arm portion 20. Furthermore, compared to the case where the block array 30 is arranged so that the moving axis C2 coincides with the center line C1 of the cylinder, the internal space of the cylinders 21, 22, 23, and 24 can be utilized more effectively.

[0055] Furthermore, in this embodiment, from the viewpoint of ensuring rigidity, a plurality of cylindrical bodies 21, 22, 23, and 24 arranged in a nested structure are adopted as the fixing mechanism (arm 20). However, the fixing mechanism may also be a structure in which polyhedral bodies such as triangular cylindrical bodies, quadrangular cylindrical bodies, or cylindrical bodies such as elliptical cylindrical bodies are arranged in a nested structure.

[0056] Furthermore, relative to the entry / exit position Pe, as long as the relative positions of the front ends of the block array delivered from the housing section in two directions orthogonal to the connection direction can be fixed, the fixing mechanism is not limited to multiple cylinders 21, 22, 23, 24 that are firmly arranged in a multi-level nested structure. The fixing mechanism can also be composed of multiple direct-acting guide mechanisms connected in series. For example... Figure 18 , Figure 19 As shown, for example, the base supporting the guide rail of the last of the multiple direct-acting guide mechanisms 61, 62, and 63 is horizontally fixed to the housing portion 10, and the slider of the foremost direct-acting guide mechanism 61 is connected to the foremost block 40 of the block array 30 via an L-shaped connector 64. The multiple direct-acting guide mechanisms 61, 62, and 63 have high rigidity in two directions orthogonal to their sliding direction (X-axis direction) (Y-axis direction and Z-axis direction). Therefore, the multiple direct-acting guide mechanisms 61, 62, and 63 can relatively fix the front end position of the block array 30 relative to the entry / exit position of the block array 30 in the Y-axis direction and the Z-axis direction. In other words, even a direct-acting telescopic mechanism using a direct-acting guide mechanism in the fixed mechanism can produce the same effect as a direct-acting telescopic mechanism 1 when the fixed mechanism uses a telescopic structure.

[0057] While some embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. In fact, the novel methods and systems described herein can be embodied in various other forms; furthermore, various omissions, substitutions, and modifications can be made to the implementation of the methods and systems described herein without departing from the spirit of the invention. The appended claims and their equivalents are intended to cover forms or modifications falling within the scope and spirit of the invention.

Claims

1. A direct-acting telescopic mechanism, characterized in that, have: The housing is box-shaped and hollow inside, with an opening on the upper side. The arm is composed of multiple cylindrical bodies arranged in a multi-level nested structure, and the rear end of the arm is fixed to the upper part of the housing. A block array, composed of multiple interconnected blocks, is housed within the housing portion. The block array is inserted into the arm portion, and the front end of the block array is connected to the front end of the arm portion. A conveying mechanism, for extending and retracting the arm, delivers the block column from the housing portion through the opening and pulls the block column into the housing portion; The centerline of the block column is offset downwards relative to the centerline of the arm. The linear telescopic mechanism also has a limiting structure that restricts the entry and exit positions of the block column on the housing portion in two directions orthogonal to the connection direction of the block column. The limiting structure is a square-tube shaped support through which the block column passes. The inner shape and inner dimensions of the support match the outer shape and outer dimensions of the block so that the block column passing through the support abuts against the inner wall of the support.

2. The direct-acting telescopic mechanism according to claim 1, characterized in that, The blocks are connected such that, with the front and rear end faces of adjacent blocks abutting each other to arrange the block column in a straight line, the blocks are restricted from rotating in the forward direction, while allowing the blocks to rotate in the reverse direction.

3. The direct-acting telescopic mechanism according to claim 1, characterized in that, The block column bears the load in the connection direction. Multiple cylindrical bodies or multiple direct-acting guide mechanisms arranged in a multi-level nested structure bear loads in two directions orthogonal to the connection direction.

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