Link mechanism

Abstract

The present invention provides a link mechanism that allows a specific part to be displaced linearly. [Solution] The link mechanism comprises a first link member to a seventh link member (12L1 to 12L7). In the link mechanism, the A, B, C, D, E, G, and P axes (18A to 18P), which are the pivot axes, are set as follows: In a view in the Z direction, the line passing through the A, B, and D axes is a straight line, the quadrilateral formed by the line passing through the A, E, P, and D axes is a parallelogram, the distance from the A axis to the B axis, the distance from the A axis to the D axis, the distance from the E axis to the C axis, and the distance from the E axis to the P axis are all the same, the distance from the A axis to the G axis, the distance from the C axis to the G axis are all the same, and the distance from the A axis to the E axis, the distance from the B axis to the C axis, and the distance from the D axis to the P axis are all the same.

Description

[Technical Field]

[0001] This invention relates to a link mechanism. [Background technology]

[0002] Conventionally, link mechanisms that achieve strictly linear motion are known (see, for example, Patent Document 1, Patent Document 2, Non-Patent Document 1, and Non-Patent Document 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2009-291290 [Patent Document 2] Japanese Patent Application Publication No. 5-104383 [Non-patent literature]

[0004] [Non-Patent Document 1] "Mechanism" by Masao Kubota, published by Morikita Publishing Co., Ltd., 1974, pp. 162-165 [Non-Patent Document 2] "New Edition of Fundamentals of Machinery," by Gonpachi Asakawa, edited by the Fundamentals of Machinery Committee, published by Rikogakusha in 1966, pages 76-80 and 87. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] While the above-mentioned configurations described in Patent Documents 1, 2, Non-Patent Documents 1 and 2 have been proposed as link mechanisms for achieving strictly linear motion, there may be cases where other configurations of link mechanisms are needed to achieve strictly linear motion (displacing a specific part in a straight line).

[0006] This invention aims to provide a link mechanism that can linearly displace a specific part, taking the above facts into consideration. [Means for solving the problem]

[0007] A link mechanism according to a first aspect of the present invention is a link mechanism provided in a three-dimensional space defined by mutually orthogonal X, Y, and Z axes, comprising: an A axis parallel to the Z axis direction and immovable in the X and Y axis directions; a first link member supported on the A axis in a rotatable manner; a second link member supported on the A axis in a rotatable manner; a D axis set at a position away from the A axis on the first link member and parallel to the Z axis direction; and a D axis supported on the D axis in a rotatable manner A third link member is supported; an E-axis is set on the second link member at a position away from the A-axis and parallel to the Z-axis; a fourth link member is supported on the E-axis in a rotatable manner; a P-axis is pivotally supported on the third link member at a position away from the D-axis and on the fourth link member at a position away from the E-axis and parallel to the Z-axis; a G-axis is positioned away from the A-axis, parallel to the Z-axis and immobile in the X-axis and Y-axis directions; and a part of the G-axis is rotatable A supported fifth link member, a B axis set on the first link member at a position opposite to the D axis with respect to the A axis and parallel to the Z axis direction, a sixth link member supported on the B axis in a rotatable manner, a C axis pivotally supporting the fifth link member at a position away from the G axis and the sixth link member at a position away from the B axis and parallel to the Z axis direction, and a part of the E axis supported on the C axis in a rotatable manner, and a part of the C axis at a position away from the E axis is rotatable The device comprises a seventh link member supported in a functional state, wherein, in the view in the Z direction, the lines passing through the A axis, the B axis, and the D axis are straight lines, the quadrilateral formed by the lines passing through the A axis, the E axis, the P axis, and the D axis is a parallelogram, the distance from the A axis to the B axis, the distance from the A axis to the D axis, the distance from the E axis to the C axis, and the distance from the E axis to the P axis are equal to each other, and the distance from the A axis to the G axis and the distance from the C axis to the G axis are equal to each other.The distance from the A axis to the E axis, the distance from the B axis to the C axis, and the distance from the D axis to the P axis are the same as each other.

[0008] In the link mechanism according to the second aspect of the present invention, in the link mechanism according to the first aspect, in the view in the Z direction, the C axis is provided inside a parallelogram formed by a line passing through the A axis, the E axis, the P axis, and the D axis.

[0009] In the link mechanism according to the third aspect of the present invention, in the link mechanism according to the first aspect, in the view in the Z direction, the C axis is provided outside a parallelogram formed by a line passing through the A axis, the E axis, the P axis, and the D axis.

Advantages of the Invention

[0010] According to the link mechanism of the present invention, an excellent effect that a specific portion can be linearly displaced can be achieved.

Brief Description of the Drawings

[0011] [Figure 1] It is a side view showing the link mechanism of the first embodiment. [Figure 2] It is a diagram showing a simplified link mechanism shown in FIG. 1. [Figure 3] It is a diagram obtained by rotating the link mechanism shown in FIG. 2 clockwise by α° around point A. [Figure 4] It is a side view showing the link mechanism of the second embodiment. [Figure 5] It is a side view showing the link mechanism of the third embodiment. [Figure 6] It is a side view showing the link mechanism of the fourth embodiment.

Modes for Carrying Out the Invention

[0012] The link mechanism 10 according to the first embodiment of the present invention will be described using Figures 1 to 3. The three-dimensional space in which the link mechanism 10 is provided will be defined by mutually orthogonal X, Y, and Z axes. Figure 1 shows the X and Y axes. One side of the X axis is to the right of the plane of Figure 1, and the other side of the X axis is to the left of the plane of Figure 1. One side of the Y axis is upward of the plane of Figure 1, and the other side of the Y axis is downward of the plane of Figure 1. One side of the Z axis is towards the viewer in Figure 1, and the other side of the Z axis is in the depth direction of the plane of Figure 1.

[0013] The link mechanism 10 is composed of seven link members (first link member 12L1, second link member 12L2, third link member 12L3, fourth link member 12L4, fifth link member 12L5, sixth link member 12L6, and seventh link member 12L7) and seven link pins (A link pin 14A, B link pin 14B, C link pin 14C, D link pin 14D, E link pin 14E, G link pin 14G, and P link pin 14P) which have at least one of the functions of rotatably supporting the link members and rotatably connecting the link members to each other. Each link member is an elongated member that extends in a direction perpendicular to the Z-axis direction.

[0014] The longitudinal center of the first link member 12L1 is fixed to the link base 16 via an A-link pin 14A. Here, the A-link pin 14A is a member that supports the longitudinal center of the first link member 12L1 so as to be rotatable around an A-axis 18A parallel to the Z-axis direction, and is also a member that rotatably connects the longitudinal center of the first link member 12L1 to one end of the second link member 12L2 in the longitudinal direction. The link base 16 functions as a base to which the link mechanism 10 is fixed. Therefore, the portion of the first link member 12L1 supported by the A-link pin 14A (the longitudinal center of the first link member 12L1) is immobile in the X-axis direction and the Y-axis direction.

[0015] One end of the second link member 12L2 in the longitudinal direction is rotatably connected to the longitudinal center of the first link member 12L1 via the A link pin 14A.

[0016] One end of the third link member 12L3 in the longitudinal direction is connected to one end of the first link member 12L1 in the longitudinal direction via a D-link pin 14D. The D-link pin 14D is a member that connects the first link member 12L1 and the third link member 12L3 so that they can rotate around a D-axis 18D parallel to the Z-axis direction.

[0017] One end of the fourth link member 12L4 in the longitudinal direction is rotatably connected to the other end of the second link member 12L2 in the longitudinal direction via an E-link pin 14E. The E-link pin 14E is a member that connects the second link member 12L2, the fourth link member 12L4, and the seventh link member 12L7 so that they can rotate around an E-axis 18E parallel to the Z-axis direction. Furthermore, the other end of the fourth link member 12L4 in the longitudinal direction is rotatably connected to the other end of the third link member 12L3 in the longitudinal direction via a P-link pin 14P. The P-link pin 14P is a member that connects the third link member 12L3 and the fourth link member 12L4 so that they can rotate around a P-axis 18P parallel to the Z-axis direction.

[0018] One end of the fifth link member 12L5 in the longitudinal direction is fixed to the link base 16 via a G link pin 14G. Here, the G link pin 14G is a member that supports the one end of the fifth link member 12L5 in the longitudinal direction so that it can rotate around the G axis 18G which is parallel to the Z axis direction. As described above, the link base 16 functions as a base to which the link mechanism 10 is fixed. Therefore, the part of the fifth link member 12L5 supported by the G link pin 14G (one end of the fifth link member 12L5 in the longitudinal direction) cannot be displaced in the X axis direction and the Y axis direction.

[0019] One longitudinal end of the sixth link member 12L6 is rotatably connected to the other longitudinal end of the first link member 12L1 via a B link pin 14B. The B link pin 14B is a member that connects the first link member 12L1 and the sixth link member 12L6 so as to be rotatable around a B axis 18B parallel to the Z axis. The B axis 18B is located on the opposite side of the D axis 18D relative to the A axis 18A. Furthermore, the other longitudinal end of the sixth link member 12L6 is rotatably connected to the other longitudinal end of the fifth link member 12L5 via a C link pin 14C. The C link pin 14C is a member that connects the fifth link member 12L5, the sixth link member 12L6, and the seventh link member 12L7 so as to be rotatable around a C axis 18C parallel to the Z axis.

[0020] One longitudinal end of the seventh link member 12L7 is connected to the other longitudinal end of the second link member 12L2 and one longitudinal end of the fourth link member 12L4 via an E link pin 14E. Furthermore, the other longitudinal end of the seventh link member 12L7 is connected to the other longitudinal end of the fifth link member 12L5 and the other longitudinal end of the sixth link member 12L6 via a C link pin 14C.

[0021] In this embodiment, the dimensions of each link member and the position of each link pin are set so as to satisfy the following conditions 1 to 5 when viewed in the Z direction.

[0022] Condition 1: In the Z-direction view, the line passing through the A-axis 18A, B-axis 18B, and D-axis 18D is a straight line.

[0023] Condition 2: In the Z-direction view, the quadrilateral formed by the lines passing through the A-axis 18A, E-axis 18E, P-axis 18P, and D-axis 18D is a parallelogram.

[0024] Condition 3: In the Z-direction view, the distance from A-axis 18A to B-axis 18B, the distance from A-axis 18A to D-axis 18D, the distance from E-axis 18E to C-axis 18C, and the distance from E-axis 18E to P-axis 18P are all equal to each other.

[0025] Condition 4: In the Z-direction view, the distance from the A-axis 18A to the G-axis 18G and the distance from the C-axis 18C to the G-axis 18G are the same.

[0026] Condition 5: In the Z-direction view, the distance from the A-axis 18A to the E-axis 18E, the distance from the B-axis 18B to the C-axis 18C, and the distance from the D-axis 18D to the P-axis 18P are all equal.

[0027] In this embodiment, the distance from axis A 18A to axis B 18B, the distance from axis A 18A to axis D 18D, the distance from axis E 18E to axis C 18C, and the distance from axis E 18E to axis P 18P are set to "a (for example, a meters)". The distance from axis A 18A to axis G 18G and the distance from axis C 18C to axis G 18G are set to "b (for example, b meters)". Furthermore, the distance from axis A 18A to axis E 18E, the distance from axis B 18B to axis C 18C, and the distance from axis D 18D to axis P 18P are set to "c (for example, c meters)". In this embodiment, distance "c" is longer than distances "a" and "b". Also, in this embodiment, in the Z-direction view, axis C 18C is located inside the parallelogram formed by the lines passing through axis A 18A, axis E 18E, axis P 18P, and axis D 18D.

[0028] Figure 2 shows the link members (first link member 12L1, second link member 12L2, third link member 12L3, fourth link member 12L4, fifth link member 12L5, sixth link member 12L6, and seventh link member 12L7) of the link mechanism 10 shown in Figure 1 as lines, and each axis (A axis 18A, B axis 18B, C axis 18C, D axis 18D, E axis 18E, G axis 18G, and P axis 18P) as points. Points A, B, C, D, E, G, and P correspond to the A axis 18A, B axis 18B, C axis 18C, D axis 18D, E axis 18E, G axis 18G, and P axis 18P, respectively. In the following explanation, line segments connecting each point may be shown using combinations of letters representing points A, B, C, D, E, G, and P. For example, AE is a line segment connecting point A and point E, and corresponds to the line segment representing the second link member 12L2.

[0029] As shown in Figure 2 (see also Figure 1), point A(0,0) is placed at the intersection of the X and Y axes, and point G(b,0) is placed on the X axis. A circle with radius b is drawn with point G as the center. Point C is taken on the circumference of this circle, forming quadrilateral ABCE composed of points A, B, C, and E. In quadrilateral ABCE, sides AE and BC intersect. Point D is placed on the extension of line segment BA such that BA=AD=a. A parallelogram AEPD is formed with sides AE=c and AD=a, and the point opposite point A is taken as P. When side CG is rotated clockwise, point P will undergo linear motion parallel to the y axis. In this way, the link mechanism 10 of this embodiment allows a specific part (the part where axis P 18P is located) to be displaced linearly.

[0030] Here, we consider the range of θ in which the link mechanism 10 can operate, given that ∠AGC = θ. The limit of θ in which the link mechanism 10 can operate corresponds to the state where all points B, A, C, D, E, and P are aligned on the extension of line segment AC. Let's call this θ θ1. Since AB = a and BC = c, we have the relationship AC = ca. AC can be expressed as 2b·sin(θ1 / 2). That is, the following relationships (1) and (2) hold. AC=ca=2b sin(θ1 / 2) Formula (1) sin(θ1 / 2)=(ca) / 2b...Equation (2)

[0031] From the above, θ1 can be expressed by the following equation (3). θ1=2·arcsin{(ca) / 2b} ···Equation (3)

[0032] Here, as a specific example, substituting a=35, b=30, and c=50, we get θ1=28.96°. Therefore, the range of θ in which the link mechanism 10 can operate is θ1 < θ < 180°. It should be noted that, as a configuration of the link mechanism to which this invention is applied, a link mechanism with a configuration that is symmetrical with respect to the x-axis with respect to the configuration when θ1 < θ < 180° (the configuration of the link mechanism 10 in the first embodiment) can also be adopted (a configuration where -180° < θ < -θ1).

[0033] Next, we will mathematically prove that point P in this invention undergoes strictly linear motion. That is, we will show that the x-coordinate (Px) of point P is a constant. First, we will show that points A, C, and P are collinear in Figure 2 (when θ is an acute angle).

[0034] As shown in Figure 3, draw a circle with radius a centered at point E, and let P' be the intersection point with the extension of AC. Triangle ECP' is an isosceles triangle. Take point R such that ∠ECR = ∠EP'R. Since triangles ABC and AEC are congruent, BQ = ER. Therefore, triangles ABQ and CER are congruent. Consequently, the relationship ∠EP'R = ∠BAQ holds. In other words, AB and P'E are parallel. Quadrilateral ADPE is a parallelogram with two sides at distance a and distance c, so points P and P' coincide. Therefore, points A, C, and P are collinear.

[0035] As shown in Figure 2, Px can be expressed by the following equation (4). Px=AP·cosα...Equation (4)

[0036] Since triangle ACF is a right-angled triangle, the following relationship (5) holds true. AC = 2b·cosα ··· Equation (5)

[0037] As shown in Fig. 3, with respect to AP, the following relationship of Equation (6) holds. AP = AC + 2·X ··· Equation (6)

[0038] Also, for △BQC, c 2 = BQ 2 +(X + AC) 2 =(a 2 - X 2 ) + X 2 + 2·X·AC + AC 2 = a 2 + 2·X·AC + AC 2 By going through the calculation process of the above, the following relationship of Equation (7) holds. c 2 = a 2 + 2·X·AC + AC 2 ··· Equation (7)

[0039] Also, substituting Equation (6) into Equation (7), c 2 = a 2 +(AP - AC)·AC + AC 2 = a 2 + AP·AC - AC 2 + AC 2 = a 2 + AP·AC. By going through the calculation process of the above, the following relationship of Equation (8) holds. c 2 = a 2 + AP·AC ··· Equation (8)

[0040] Also, from Equation (8), the following relationship of Equation (9) holds. AP = (c 2 - a 2 ) / AC ··· Equation (9)

[0041] Also, from Equation (4) and Equation (9), the following relationship of Equation (10) holds. Px = {(c 2 - a 2 ) / AC}·cosα ··· Equation (10)

[0042] Furthermore, from equations (5) and (10), the following relationship (11) holds true. That is, the following relationship (12) holds true. Px={(c 2 -a 2 ) / 2b cosα} cosα Formula (11) Px={(c 2 -a 2 ) / 2b}...Equation (12)

[0043] From equation (12) above, Px is a constant. This proves that point P undergoes linear motion parallel to the Y-axis.

[0044] (Link mechanisms 20, 22, 24 of other embodiments) Next, link mechanisms 20, 22, and 24 of other embodiments will be described. In addition, in link mechanisms 20, 22, and 24 of other embodiments, components etc. that correspond to the link mechanism 10 of the first embodiment described above will be denoted by the same reference numerals as those corresponding to the link mechanism 10 of the first embodiment, and detailed descriptions will be omitted.

[0045] As shown in Figure 4, the link mechanism 20 of the second embodiment differs from the link mechanism 10 of the first embodiment in that the parallelogram formed by lines passing through the A axis 18A, E axis 18E, P axis 18P, and D axis 18D is formed on the G axis 18G side, but basically the same settings as the link mechanism 10 of the first embodiment are applied.

[0046] As shown in Figure 5, the link mechanism 22 of the third embodiment differs from the link mechanism 10 of the first embodiment in that the C axis 18C is positioned outside the parallelogram formed by lines passing through the A axis 18A, E axis 18E, P axis 18P, and D axis 18D, but basically the same settings as the link mechanism 10 of the first embodiment are applied.

[0047] As shown in Figure 6, the link mechanism 24 of the fourth embodiment differs from the link mechanism 22 of the third embodiment in that the C axis 18C is provided on the G axis 18G side relative to the first link member 12L1, but basically the same settings as the link mechanism 22 of the third embodiment are applied.

[0048] In the link mechanisms 20, 22, and 24 of the other embodiments described above, a specific part (the part containing the P-axis 18P) can be linearly displaced, similar to the link mechanism 10 of the first embodiment.

[0049] The link mechanism of this invention can be used, for example, as a suspension system for the rear wheel of a motorcycle or as a means of moving products during the manufacturing process in a factory, but it can also be applied to a variety of other uses.

[0050] Furthermore, the link mechanism of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0051] 10 Link mechanism 12L1 First link member 12L2 Second link member 12L3 Third link member 12L4 Fourth link member 12L5 Fifth link member 12L6 Sixth link member 12L7 Seventh link member 18A A-axis 18B B axis 18C C axis 18D D axis 18E E-axis 18G G-axis 18P P axis 20 Link mechanism 22 Link mechanism 24 Link mechanism

Claims

1. A link mechanism provided in a three-dimensional space defined by mutually orthogonal X, Y, and Z axes, The A axis is parallel to the Z-axis and cannot be displaced in the X-axis and Y-axis directions, In the aforementioned A-axis, a first link member is supported in a state in which a part thereof can rotate, In the aforementioned A-axis, a second link member is supported in a state in which a part thereof can rotate, In the first link member, the D axis is set at a position separate from the A axis and parallel to the Z axis direction, In the aforementioned D-axis, a third link member is supported in a manner that allows a portion of it to rotate, In the second link member, the E axis is set at a position separate from the A axis and parallel to the Z axis direction, In the aforementioned E-axis, a fourth link member is supported in a manner that allows a portion of it to rotate, The third link member is pivotally supported at a position away from the D axis, and the fourth link member is pivotally supported at a position away from the E axis, and the P axis is parallel to the Z axis direction, A G-axis, located at a position separate from the A-axis, is parallel to the Z-axis and cannot be displaced in the X-axis and Y-axis directions, In the aforementioned G-axis, a fifth link member is supported in a manner that allows a portion of it to rotate, In the first link member, the B axis is set to a position opposite to the D axis with respect to the A axis and is parallel to the Z axis direction, In the aforementioned B-axis, a sixth link member is supported in a manner that allows a portion of it to rotate, The fifth link member is pivotally supported at a position away from the G axis, and the sixth link member is pivotally supported at a position away from the B axis, and the C axis is parallel to the Z axis direction, A seventh link member is supported in a rotatable manner in part on the E axis, and in part on the C axis, which is located away from the E axis, a portion of which is also supported in a rotatable manner. It is equipped with, In the Z-direction view, The line passing through axis A, axis B, and axis D is a straight line. The quadrilateral formed by the lines passing through the A axis, the E axis, the P axis, and the D axis is a parallelogram. The distance from axis A to axis B, the distance from axis A to axis D, the distance from axis E to axis C, and the distance from axis E to axis P are all the same. The distance from axis A to axis G and the distance from axis C to axis G are the same. A linkage mechanism in which the distance from axis A to axis E, the distance from axis B to axis C, and the distance from axis D to axis P are all the same.

2. In the Z-direction view, The link mechanism according to claim 1, wherein the C axis is provided inside a parallelogram formed by lines passing through the A axis, the E axis, the P axis, and the D axis.

3. In the Z-direction view, The link mechanism according to claim 1, wherein the C axis is provided outside the parallelogram formed by lines passing through the A axis, the E axis, the P axis, and the D axis.

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