Chain drive system

Abstract

To smooth the movement of the chain in sections where it curves during movement. [Solution] The chain drive device comprises a sprocket 6, a case 7 in which the sprocket 6 is housed, and a chain configured to move forward and backward from the case 7 in accordance with the rotation of the sprocket 6 by meshing with the sprocket 6. In the first straight guide section 21 of the case 7, the sprocket 6 meshes with adjacent shaft members, and in the second straight guide section 22 beyond the curved guide section 23 of the case 7, the sprocket 6 also meshes with adjacent shaft members. If we define a virtual line S1 as a virtual line extending through the center P1 of the sprocket 6 in a direction perpendicular to the direction in which the first and second straight guide sections extend, and define the distance between virtual lines S1 and S2 as L1, and define the pitch of the multiple shaft members of the chain as L2, then L1 and L2 satisfy the relationship given by equation (1).

Description

Technical Field

[0001] The present invention relates to a chain drive device.

Background Art

[0002] Patent Document 1 describes a movable body moving device. As shown in FIG. 13, the movable body moving device 70 includes an engagement chain 72 having a pair of chain members 71 that mesh with each other and are integrated, a sprocket 73 that meshes with the chain member 71, and a movable body (not shown) that moves forward and backward together with the engagement chain 72.

[0003] The sprocket 73 has a drive sprocket 73a connected to a drive source 74 and a driven sprocket 73b that is driven in accordance with the drive of the drive sprocket 73a. When the drive sprocket 73a and the driven sprocket 73b are rotated to move the pair of chain members 71 in the traveling direction, the pair of chain members 71 mesh with each other and are integrated into a straight bar shape. Since the movable body is connected to the tip of the integrated straight bar-shaped engagement chain 72, the movable body can be moved forward and backward together with the straight bar-shaped integrated engagement chain 72 by rotating the drive sprocket 73a and the driven sprocket 73b.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the movable body moving device 70 described in Patent Document 1, etc., when a load is applied to the chain member 71 when the sprocket 73 is rotated to move the meshing chain 72 forward and backward, the responsiveness of the chain member 71 to the rotation of the sprocket 73 tends to decrease. As a result of the decreased responsiveness of the chain member 71, the chain member 71 may not move smoothly, for example, in a configuration in which the chain member 71 moves in a curved manner within the case. [Means for solving the problem]

[0006] The chain drive device of embodiment 1 comprises a sprocket, a case housing the sprocket, and a chain configured to mesh with the sprocket so as to move forward and backward from the case in accordance with the rotation of the sprocket, wherein the case has a first opening through which the chain is inserted, a first straight guide portion extending linearly from the first opening into the case, a curved guide portion extending curvedly into the case continuous with the first straight guide portion, a second straight guide portion extending linearly into the case continuous with the curved guide portion, and a second opening through which the chain is inserted continuous with the second straight guide portion, wherein the first straight guide portion and the second straight guide portion extend parallel to each other and have connecting portions on their opposing inner circumferential surfaces, the sprocket is arranged within the connecting portion, the chain has a plurality of inner links and a plurality of outer links arranged alternately in a series direction and rotatably connected to each other via a plurality of shaft members, and the chain is adjacent to the first straight guide portion The sprocket meshes between the shaft members, and in the second straight guide section beyond the curved guide section, the sprocket also meshes between adjacent shaft members. A virtual line S1 is defined as a virtual line extending through the center P1 of the sprocket in a direction perpendicular to the direction in which the first straight guide section and the second straight guide section extend. The boundary between the inner surface of the curved guide section and the inner surface of the first straight guide section is defined as boundary section P2, and the boundary between the inner surface of the curved guide section and the inner surface of the second straight guide section is defined as boundary section P Let 3 be the case. Comparing a virtual line extending through the boundary P2 in a direction perpendicular to the direction in which the first and second linear guide sections extend with a virtual line extending through the boundary P3 in a direction perpendicular to the direction in which the first and second linear guide sections extend, let the virtual line closer to the virtual line S1 be virtual line S2, let the distance between virtual line S1 and virtual line S2 be L1, and let L2 be the pitch of the multiple shaft members of the chain. The gist of this is that L1 and L2 satisfy the following relationship (1).

[0007]

number

[0008] Embodiment 3 is a chain drive device according to Embodiment 1 or Embodiment 2, wherein the chain is bendable on one side in the direction intersecting the series direction, but not on the other side in the direction intersecting the series direction.

[0009] Embodiment 4 is a chain drive device according to any one embodiment of Embodiments 1 to 3, wherein the sprocket has an involute tooth profile. Embodiment 5 is a chain drive device according to any one embodiment of Embodiments 1 to 4, wherein the first straight guide portion, the curved guide portion, and the second straight guide portion extend along the horizontal direction. [Effects of the Invention]

[0010] According to the chain drive device of the present invention, the movement of the chain can be made smoother in the section where the chain moves in a curved manner within the case. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view of a chain drive system. [Figure 2] Figure 2 is a partial perspective view of a chain drive system. [Figure 3] Figure 3 is a perspective view of the drive unit, motor, and chain. [Figure 4] Figure 4 is a perspective view of Figure 3 with the chain omitted. [Figure 5] Figure 5 is a partial perspective view of the chain. [Figure 6] Figure 6 is an exploded perspective view schematically showing a part of the chain. [Figure 7] Figure 7 is a partial left side view of the chain. [Figure 8] Figure 8 is a partial left side view of the chain in a state where the rear side is curved. [Figure 9] Figure 9 is a plan view of the drive unit and the chain. [Figure 10] Figure 10 is a plan view with the chain omitted from Figure 9. [Figure 11] Figure 11 is a plan view with the chain omitted from Figure 9. [Figure 12] Figure 12 is a plan view of the drive unit of the modification example. [Figure 13] Figure 13 is a partial plan view of the conventional chain drive device.

Embodiments for Carrying Out the Invention

[0012] An embodiment in which the chain drive device of the present invention is embodied will be described. As shown in FIGS. 1 and 2, the chain drive device 1 includes a chain 11, a motor 2 as a drive source, a drive unit 3 that moves the chain 11 forward and backward by driving the motor 2, and a pair of guide rails 4 extending along the moving direction of the chain 11. Further, the chain drive device 1 includes a slide table 5 connected to the chain 11 on the other guide rail 4b of the pair of guide rails 4. The chain drive device 1 can move a movable body (not shown) forward and backward along the other guide rail 4b by connecting the movable body to the slide table 5. Hereinafter, the direction in which the movable body moves away from the drive unit 3 is defined as the advancing direction in the forward and backward direction of the movable body, and the direction in which the movable body approaches the drive unit 3 is defined as the retreating direction in the forward and backward direction of the movable body.

[0013] Note that FIG. 2 shows a state where the cover 7b of the case 7 included in the drive unit 3 and the covers 4a1 and 4b1 included in the pair of guide rails 4 are removed. Also, the outer link plates 15 of some of the chains 11 passing through the drive unit 3 are omitted.

[0014] Hereinafter, each member constituting the chain drive device 1 will be described. <Motor> As shown in FIG. 2, the motor 2 is connected to the drive unit 3. The motor 2 has a rotating shaft (not shown), and is configured such that the sprocket 6 included in the drive unit 3 can be rotated by the rotation of the rotating shaft, as will be described later.

[0015] <Drive Unit> As shown in FIG. 2, the drive unit 3 includes a sprocket 6 and a case 7 that houses the sprocket 6.

[0016] (Case) As shown in FIGS. 3 and 4, the case 7 has a rectangular parallelepiped main body portion 7a and a cover 7b (see FIG. 1) attached to the upper surface of the main body portion 7a. The main body portion 7a has a guide portion 20 that is recessed downward from the upper surface of the main body portion 7a and extends in a groove shape along the horizontal direction.

[0017] One end portion of the guide portion 20 reaches the side surface of the main body portion 7a. This one end portion of the guide portion 20 functions as a first opening 24 through which the chain 11 is inserted. The guide portion 20 extends linearly inside the main body portion 7a from the first opening 24, and then extends curvedly along a semi-circular shape. Further, the guide portion 20 extends linearly. The other end portion of the guide portion 20 reaches the same side surface of the main body portion 7a as the first opening 24. This other end portion of the guide portion 20 functions as a second opening 25 through which the chain 11 is inserted.

[0018] In the guide section 20, the portion extending linearly from the first opening 24 is called the first linear guide section 21. The portion extending in a curved manner along the semicircular shape, continuous with the first linear guide section 21, is called the curved guide section 23. The portion extending linearly from the curved guide section 23 to the second opening 25 is called the second linear guide section 22. The first linear guide section 21 and the second linear guide section 22 extend parallel to each other. When the main body 7a of the case 7 is viewed from above, the overall shape of the guide section 20 is U-shaped.

[0019] The widths of the first straight guide section 21, the curved guide section 23, and the second straight guide section 22 are approximately the same. This width is slightly larger than the dimension in the Z direction that intersects the serial direction of the chain 11 (see Figure 5), which will be described later. The guide section 20 functions as a passage that guides the chain 11 as it moves back and forth within the case 7.

[0020] As shown in Figures 9 and 10, the direction in which the first linear guide section 21 and the second linear guide section 22 extend, in other words, the direction in which the movable body moves forward and backward, is also called the X direction. The direction perpendicular to the X direction is also called the Z direction.

[0021] As shown in Figure 10, the imaginary line S1 is defined as an imaginary line extending in the Z direction through the central axis of the sprocket 6 (hereinafter also referred to as "center P1"). The boundary between the inner circumferential surface 23a of the curved guide section 23 and the inner circumferential surface 21a of the first straight guide section 21 is defined as boundary section P2, and the boundary between the inner circumferential surface 23a of the curved guide section 23 and the inner circumferential surface 22a of the second straight guide section 22 is defined as boundary section P3.

[0022] Furthermore, by comparing the imaginary line extending in the Z direction through boundary P2 with the imaginary line extending in the Z direction through boundary P3, the imaginary line that is closer to imaginary line S1 is designated as imaginary line S2. In Figure 10, the imaginary line extending in the Z direction through boundary P2 and the imaginary line extending in the Z direction through boundary P3 are collinear.

[0023] The inner circumferential surfaces 21a, 22a, and 23a of the first straight guide section 21, the second straight guide section 22, and the curved guide section 23 are defined as surfaces located on the inner circumferential side of the U-shaped guide section 20 and extending in the vertical direction in Figure 4. The surfaces located on the outer circumferential side of the U-shaped guide section 20 and facing the inner circumferential surfaces 21a, 22a, and 23a are referred to as outer circumferential surfaces.

[0024] As shown in Figure 4, the first straight guide section 21, the second straight guide section 22, and the curved guide section 23 each have grooves 22b and 23b recessed into the inner circumference side of the guide section 20 at the lower ends of their respective inner circumferential surfaces 21a, 22a, and 23a. Note that in Figure 4, the groove on the inner circumferential surface 21a of the first straight guide section 21 is not visible.

[0025] Furthermore, the upper ends of the inner circumferential surfaces 21a, 22a, and 23a of the first straight guide section 21, the second straight guide section 22, and the curved guide section 23 are located slightly below the upper surface of the main body section 7a of the case 7. When the cover 7b is attached to the main body section 7a of the case 7, there is a gap between the cover 7b and the guide section. These grooves and gaps allow a portion of the inner link plate 14 and outer link plate 15 of the chain 11, which will be described later, to be inserted as the chain 11 moves back and forth within the guide section 20. This allows the axial member of the chain 11, which will be described later, to move along the inner circumferential surfaces 21a, 22a, and 23a of the first straight guide section 21, the second straight guide section 22, and the curved guide section 23 as the chain 11 moves back and forth within the guide section 20.

[0026] In other words, the shaft member of the chain 11 is configured to move while in contact with the inner circumferential surfaces 21a, 22a, and 23a of the first straight guide section 21, the second straight guide section 22, and the curved guide section 23. However, the shaft member of the chain 11 does not need to maintain contact with the inner circumferential surfaces 21a, 22a, and 23a of the first straight guide section 21, the second straight guide section 22, and the curved guide section 23 while moving; it may temporarily move away from the inner circumferential surfaces 21a, 22a, and 23a.

[0027] As shown in Figures 4 and 10, the first straight guide section 21 and the second straight guide section 22 have connecting sections 26 on their opposing inner circumferential surfaces 21a and 22a. The connecting sections 26 are formed at the end of the first straight guide section 21 on the curved guide section 23 side. Similarly, the connecting sections 26 are formed at the end of the second straight guide section 22 on the curved guide section 23 side. The connecting sections 26 are also formed so that the first straight guide section 21 and the second straight guide section 22 are in direct communication. The sprocket 6 is positioned at the location where these connecting sections 26 are formed. The central axis of the sprocket 6 extends downward within the main body section 7a of the case 7. The central axis of the sprocket 6 is configured to rotate in conjunction with the rotation of the motor 2's rotation axis in the lower part of the main body section 7a.

[0028] (sprocket) As shown in Figures 3 and 4, the sprocket 6 has an involute tooth profile. An involute tooth profile means a tooth that has an involute curve. The sprocket 6 shown in Figure 10 has an even number of 16 involute teeth. Part of the involute tooth profile of the sprocket 6 penetrates into the first linear guide section 21 and the second linear guide section 22 in the main body 7a of the case 7. Therefore, when the chain 11 is inserted into the first linear guide section 21, the involute tooth profile of the sprocket 6 meshes with adjacent shaft members of the chain 11, which will be described later. Similarly, within the second linear guide section 22, the involute tooth profile of the sprocket 6 meshes with adjacent shaft members of the chain 11. By rotating the sprocket 6, the chain 11 can be moved forward and backward starting from the two meshed points within the first linear guide section 21 and the second linear guide section 22. Furthermore, because the sprocket 6 has an involute tooth profile, the chain 11 can move more smoothly as the sprocket 6 rotates.

[0029] <Guide rail> As shown in Figures 2 and 4, the chain drive unit 1 has a pair of guide rails 4 connected to the main body 7a of the case 7. One guide rail 4a extends continuously to the first opening 24 of the main body 7a of the case 7. The other guide rail 4b extends continuously to the second opening 25 of the main body 7a of the case 7. One guide rail 4a is also called the first guide rail 4a. The other guide rail 4b is also called the second guide rail 4b. A slide table 5 is slidably positioned on the second guide rail 4b via guide rollers.

[0030] A chain 11 extending from the first opening 24 in the main body 7a of case 7 moves back and forth along the first guide rail 4a. Similarly, a chain 11 extending from the second opening 25 in the main body 7a of case 7 moves back and forth along the second guide rail 4b. Furthermore, the chain 11 extending from the second opening 25 in the main body 7a of case 7 is connected to a slide table 5 positioned on the second guide rail 4b. Therefore, when the chain 11 moves back and forth along the second guide rail 4b, the slide table 5 can move back and forth along with it.

[0031] <Slide Table> As shown in Figure 2, the slide table 5 is configured as a long rectangular plate along the direction in which the second guide rail 4b extends. The slide table 5 has vertical wall portions 5a extending upward from both ends in the shorter direction.

[0032] As shown in Figure 2, a guide roller (not shown) is connected to the slide table 5. The guide roller rolls along the second guide rail 4b. Because the guide roller is connected to the slide table 5, the slide table 5 is configured to move back and forth on the second guide rail 4b. In addition, a chain 11 is connected to the longitudinal end of the slide table 5. Therefore, the slide table 5 can move back and forth in accordance with the movement of the chain 11.

[0033] As shown in Figure 1, when the cover 4b1 is attached to the second guide rail 4b, the vertical wall portion 5a of the slide table 5 is configured to protrude upward from the gap between the second guide rail 4b and the cover 4b1. A movable body is connected to this vertical wall portion 5a. The movable body is not particularly limited, and any member can be used. A specific example of a movable body is, for example, the moving part of a machine tool.

[0034] <chain> As shown in Figure 5, the chain 11 comprises a plurality of inner links 12 and a plurality of outer links 13 arranged in the series direction of the chain 11. The plurality of inner links 12 and outer links 13 are arranged to be alternately positioned in the series direction. The plurality of inner links 12 and outer links 13 are rotatably connected to each other via bushings 16, which will be described later as shaft members.

[0035] In the explanation of Figures 5 to 8, the direction in which the multiple inner links 12 and outer links 13 extend in series, based on the point where the multiple inner links 12 and outer links 13 extend linearly, is defined as the front-rear direction X. The direction perpendicular to the front-rear direction X, where the pair of link plates face each other, is defined as the left-right direction Y. The direction perpendicular to both the front-rear direction X and the left-right direction Y is defined as the up-down direction Z.

[0036] In Figure 5, the left side is considered the front in the front-to-back direction (X), and the right side is considered the rear. In Figure 1, the far side is considered the right side in the left-to-right direction (Y), and the near side is considered the left. In Figure 1, the top side is considered the top in the up-to-down direction (Z), and the bottom side is considered the bottom.

[0037] As shown in Figures 5 and 6, the inner link 12 comprises a pair of inner link plates 14 that are spaced apart and facing each other in the left-right direction Y. The inner link 12 also comprises a pair of cylindrical bushings 16 that serve as shaft members, positioned between the pair of inner link plates 14 and connecting them to each other. Specifically, the inner link plates 14 have through holes 14a, and the pair of inner link plates 14 are connected by the insertion of the bushings 16 into these through holes 14a.

[0038] As shown in Figures 5 and 6, the inner link 12 is provided with a pair of connecting pins 17 located above the pair of bushings 16 and connecting the pair of inner link plates 14 together. The connecting pin 17 located at the front is designated as the first connecting pin 17a, and the connecting pin 17 located at the rear is designated as the second connecting pin 17b. Specifically, the inner link plates 14 have through holes 14b, and the pair of inner link plates 14 are also connected by the insertion of the connecting pins 17 into these through holes 14b. The connecting pins 17 pass through the pair of inner link plates 14 and protrude outwards on both sides in the left-right direction Y.

[0039] As shown in Figures 5 and 6, the outer link 13 comprises a pair of outer link plates 15 that are spaced apart and facing each other in the left-right direction Y of the chain 11. The outer link 13 also comprises a rod-shaped body pin 18 that is rotatably inserted into the bushing 16. The body pin 18 located at the front is designated as the first body pin 18a, and the body pin 18 located at the rear is designated as the second body pin 18b.

[0040] The pair of outer link plates 15 are positioned so as to sandwich the pair of inner link plates 14 from the outside, and are located at both ends of the main body pins 18. The pair of main body pins 18 are located between the pair of outer link plates 15. Specifically, the outer link plates 15 have through holes 15c, and the pair of outer link plates 15 are connected to each other by inserting the main body pins 18 into these through holes 15c. As shown in Figures 5 and 6, the pair of outer link plates 15 have the same shape. The outer link plate 15 is provided with a pair of engagement grooves. The engagement groove located at the front is called the first engagement groove 15a, and the engagement groove located at the rear is called the second engagement groove 15b. Both of the pair of outer link plates 15 have the first engagement groove 15a and the second engagement groove 15b.

[0041] As shown in Figure 7, when the chain 11 is extended in a straight line, the first connecting pin 17a of the inner link plate 14 engages with the second engagement groove 15b of the outer link plate 15 adjacent to it on the front side. Also, the second connecting pin 17b of the inner link plate 14 engages with the first engagement groove 15a of the outer link plate 15 adjacent to it on the rear side.

[0042] Furthermore, the line L3, through which the center of the second connecting pin 17b engaged with the first engaging groove 15a passes and the center of the first connecting pin 17a engaged with the second engaging groove 15b, extends parallel to the line L4, which passes through the centers of the pair of through holes 15c in the outer link plate 15. Also, lines L3 and L4 extend linearly along the front-rear direction X in which the chain 11 extends.

[0043] As shown in Figure 7, when a load is applied to the rear end of the chain 11 in a forward direction along the front-rear direction X (see arrow A), the chain 11 can receive the load at the engagement point between the first connecting pin 17a and the second engagement groove 15b. Similarly, it can receive the load at the engagement point between the second connecting pin 17b and the first engagement groove 15a. In addition, it can receive the load at the engagement points between the first main body pin 18a and the bushing 16 (see Figure 6), and between the second main body pin 18b and the bushing 16 (see Figure 6). That is, the load can be received at two points along lines L3 and L4 (arrows a and b), and the forward load can be distributed and received at two points. Furthermore, since lines L3 and L4 are parallel and extend along the direction in which the chain 11 extends, the load can be distributed in a balanced manner. This makes it possible to move the chain 11 in a linear motion in a more stable state.

[0044] Furthermore, even when a load is applied to the rear end of the chain 11 in a direction pulling towards the rear (opposite direction of arrow A), the first engagement groove 15a and the second engagement groove 15b extend at an inclination with respect to the front-rear direction X, making it difficult for the engagement between these engagement grooves and the connecting pin 17 to be released. As a result, the load directed towards the rear is distributed and received at two points, making it possible to move the chain 11 in a more stable linear motion.

[0045] As shown in Figure 8, to release the chain 11 from its straight state, the inner link 12 is rotated clockwise around the second main body pin 18b at any position on the chain 11. This releases the engagement between the second engagement groove 15b of the outer link plate 15 and the first connecting pin 17a of the inner link 12. Alternatively, the outer link plate 15 is rotated clockwise around the first main body pin 18a at any position on the chain 11. This releases the engagement between the second connecting pin 17b of the inner link 12 and the first engagement groove 15a of the outer link plate 15. By repeatedly performing at least one of the above operations, the chain 11 can be released from its straight state.

[0046] As shown in Figure 8, when the straightened state of the chain 11 is released, the chain 11 bends only downwards, in the direction that intersects the series direction in which the multiple inner links 12 and outer links 13 are connected. In other words, the chain 11 is bendable on one side in the direction that intersects the series direction, but not on the other side in the direction that intersects the series direction. Furthermore, the chain 11 can be straightened by performing the opposite operation to the operation that releases the straightened state on the bent chain 11.

[0047] A chain 11 that is bendable on one side in the direction intersecting the series direction, but not on the other side in the direction intersecting the series direction, is also called a no-backbend chain, no-backbend chain, or no-back chain. The chain 11 in this embodiment is not a no-back chain of the type in which a pair of chain members interlock, but a no-back chain composed of a single chain 11 having a plurality of inner links 12 and a plurality of outer links 13 arranged in the series direction.

[0048] If the chain 11 is a non-back chain, it becomes easier to maintain the straight position of the chain 11. Therefore, even if a load is applied to the chain 11 when the slide table 5 is moved forward and backward, the chain 11 can be moved forward and backward in a stable state.

[0049] <Chain movement mechanism in the drive unit> As shown in Figures 9 and 10, the chain 11 meshes with the sprocket 6 within the main body 7a of the case 7. Specifically, in the first straight guide section 21 of the main body 7a of the case 7, the involute teeth of the sprocket 6 are inserted between adjacent bushings 16. In the second straight guide section 22, beyond the curved guide section 23, the involute teeth of the sprocket 6 are also inserted between adjacent bushings 16. As a result, the chain 11 meshes with the sprocket 6 at two points in the radial direction at both ends of the sprocket 6 within the main body 7a of the case 7.

[0050] For example, when the sprocket 6 rotates counterclockwise with respect to the plane of the paper in Figure 9, the chain 11 moves along the inner circumferential surface 21a of the first straight guide section 21 toward the curved guide section 23 within the main body 7a of the case 7. Furthermore, while moving along the inner circumferential surface 23a of the curved guide section 23, the chain 11 also moves along the inner circumferential surface 22a of the second straight guide section 22 toward the second guide rail 4b. In other words, the chain 11 moves counterclockwise as a whole. As a result, the chain 11 moves in the advance direction along the X direction on the second guide rail 4b, allowing the slide table 5 connected to the chain 11 to move in the advance direction. When the slide table 5 has moved to its maximum extent in the advance direction, at least two links of the inner link 12 and outer link 13 remain within the first guide rail 4a at the end of the chain 11 opposite to the end on the advance direction side.

[0051] Furthermore, when the sprocket 6 rotates clockwise relative to the plane of the paper in Figure 9, the chain 11 moves in the opposite direction, resulting in an overall clockwise movement. Therefore, the slide table 5 connected to the chain 11 can be moved in the exit direction along the X direction.

[0052] <Mechanism and Effects> The operation of the chain drive device 1 of this embodiment will now be described. As shown in Figure 10, let virtual line S1 be a virtual line extending in the Z direction through the central axis of the sprocket 6 (hereinafter also referred to as "center P1"). Boundary P2 is defined as the boundary between the inner surface 23a of the curved guide section 23 and the inner surface 21a of the first straight guide section 21, and boundary P3 is defined as the boundary between the inner surface 23a of the curved guide section 23 and the inner surface 22a of the second straight guide section 22. Comparing the virtual line extending in the Z direction through boundary P2 with the virtual line extending in the Z direction through boundary P3, the virtual line that is closer to virtual line S1 is defined as virtual line S2.

[0053] In Figure 10, the imaginary line extending in the Z direction through boundary P2 and the imaginary line extending in the Z direction through boundary P3 are collinear. Let L1 be the distance in the X direction between imaginary line S1 and imaginary line S2.

[0054] Furthermore, as shown in Figure 9, the pitch of the bushings 16, which serve as multiple shaft members of the chain 11, is defined as L2. Then, in the chain drive device 1 of this embodiment, L1 and L2 satisfy the following relationship (1).

[0055]

number

[0056] Furthermore, L1 is preferably 10 times or less than L2, more preferably 8 times or less, and even more preferably 5 times or less. When L1 is 10 times or less than L2, the dimensions of the main body portion 7a of the case 7 can be made relatively smaller, which contributes to miniaturization of the chain drive device 1.

[0057] As shown in Figure 11, among the multiple bushings 16 of the chain 11, the center of the bushing 16 that is engaged with the sprocket 6 in the first straight guide section 21 is positioned on the imaginary line S1. From this state, when the sprocket 6 rotates counterclockwise, the bushing 16 moves along the inner circumferential surface 21a of the first straight guide section 21, the inner circumferential surface 23a of the curved guide section 23, and the inner circumferential surface 22a of the second straight guide section 22. After that, the bushing 16 is engaged with the sprocket 6 again on the imaginary line S1 of the second straight guide section 22. The movement path of the bushing 16 at this time is denoted as the imaginary line S3. Then, it is preferable that the length of the imaginary line S3 is an integer multiple of L2.

[0058] If the length of the virtual line S3 is an integer multiple of L2, it becomes possible to move the bushing 16 while suppressing loosening of the bushing 16 along the movement path of the bushing 16 represented by the virtual line S3. This further improves the responsiveness of the chain 11 to the rotation of the sprocket 6. Note that the above "integer multiple" allows for a value that includes an error of up to 5% from an integer multiple.

[0059] The effects of the chain drive device of this embodiment will be described. (1) In the chain drive device 1, let L1 be the distance in the X direction between a virtual line S1 extending in the Z direction through the center P1 of the sprocket 6 and a virtual line S2 extending in the Z direction through the boundary P2 and boundary P3. Also, let L2 be the pitch of the multiple bushings 16 of the chain 11. L1 and L2 satisfy the relationship in equation (1) above.

[0060] By satisfying the relationship in equation (1) above, the responsiveness of the chain 11 to the rotation of the sprocket 6 can be improved. As a result, when the chain 11 moves in a curved manner within the case 7, i.e., when it moves along the curved guide portion 23, the chain 11 can move smoothly along the inner circumferential surface 23a of the curved guide portion 23. Furthermore, jamming caused by the chain 11 contacting the outer circumferential surface of the curved guide portion 23 can be suppressed.

[0061] (2) The center of the bush 16 that is engaged with the sprocket 6 in the first straight guide section 21 is positioned on the imaginary line S1. From this state, the bush 16 moves along the inner circumferential surface 21a of the first straight guide section 21, the inner circumferential surface 23a of the curved guide section 23, and the inner circumferential surface 22a of the second straight guide section 22, and then engages with the sprocket 6 again on the imaginary line S1 of the second straight guide section 22. The movement path of the bush 16 at this time is defined as the imaginary line S3. The length of the imaginary line S3 is an integer multiple of L2. When the length of the imaginary line S3 is an integer multiple of L2, it becomes possible to move the bush 16 in a state where loosening of the bush 16 is suppressed in the movement path of the bush 16 represented by the imaginary line S3. This makes it possible to further improve the responsiveness of the chain 11 to the rotation of the sprocket 6.

[0062] (3) The chain 11 is bendable on one side in the direction intersecting the serial direction, but not on the other side in the direction intersecting the serial direction. Therefore, even when a load is applied to the chain 11 when the slide table 5 is moved forward and backward, it is easier to maintain the straight state of the chain 11, so that the chain 11 can be moved forward and backward in a stable state.

[0063] (4) The sprocket 6 has an involute tooth profile. Therefore, the chain 11 can move more smoothly as the sprocket 6 rotates. (5) The first straight guide section 21, the curved guide section 23, and the second straight guide section 22 extend along the horizontal direction. Therefore, the slide table 5 can be moved forward and backward along the horizontal direction.

[0064] <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0065] In this embodiment, the connecting portion 26 of the main body portion 7a of case 7 was formed at the end of the first straight guide portion 21 on the curved guide portion 23 side and at the end of the second straight guide portion 22 on the curved guide portion 23 side, but the embodiment is not limited to this.

[0066] As shown in Figure 12, for example, the connecting portion 26 of the main body portion 7a of case 7 may be formed at the portion of the first straight guide portion 21 excluding the end on the curved guide portion 23 side, and at the portion of the second straight guide portion 22 excluding the end on the curved guide portion 23 side. In this embodiment, a part of the first straight guide portion 21 and a part of the second straight guide portion 22 are located on the curved guide portion 23 side of the connecting portion 26. In Figure 12, the position along the imaginary line S2 is the boundary between the first straight guide portion 21 and the curved guide portion 23. Similarly, it is the boundary between the second straight guide portion 22 and the curved guide portion 23. In this embodiment as well, let L1 be the distance in the X direction between the imaginary line S1 extending in the Z direction through the center P1 of the sprocket 6 and the imaginary line S2 extending in the Z direction through the boundary portion P2 and boundary portion P3. Let L2 be the pitch of the multiple bushings 16 of the chain 11. L1 and L2 satisfy the relationship in equation (1) above.

[0067] In this embodiment, the curved guide portion 23 of the main body portion 7a of case 7 curved and extended along a semicircular shape, but the embodiment is not limited to this. The curved guide portion 23 may curve and extend along a shape other than a semicircular shape. For example, it may curve and extend along an elliptical or oval shape. It may have a shape in which multiple curved surfaces with multiple curvatures are combined. It may have a shape in which multiple curved surfaces and planes are combined. It may have a shape in which multiple planes are combined.

[0068] In this embodiment, the widths of the first straight guide section 21, the curved guide section 23, and the second straight guide section 22 were approximately the same, but the embodiment is not limited to this. The widths of the first straight guide section 21, the curved guide section 23, and the second straight guide section 22 may be different from each other.

[0069] In this embodiment, the imaginary line extending in the Z direction through boundary P2 of the guide portion 20 and the imaginary line extending in the Z direction through boundary P3 were on the same straight line, but the embodiment is not limited to this. The imaginary line extending in the Z direction through boundary P2 and the imaginary line extending in the Z direction through boundary P3 may be offset in the X direction. That is, the positions of boundary P2 and boundary P3 of the guide portion 20 may be offset in the X direction. In this case, the imaginary line that is closer by imaginary line S1 is called imaginary line S2.

[0070] In this embodiment, the chain 11 was bendable on one side in the direction intersecting the series direction, but not on the other side in the direction intersecting the series direction. However, the embodiment is not limited to this configuration. The chain may be configured to bend on both sides in the direction intersecting the series direction. In other words, the chain does not have to be a backless chain. For example, if the bending of the chain is suppressed by the second guide rail 4b, it can be used even if it is not a backless chain.

[0071] In this embodiment, the sprocket 6 is engaged with the chain 11 by inserting the involute tooth profile of the sprocket 6 between adjacent bushings 16, but the embodiment is not limited to this. For example, the chain 11 may have rollers attached to the outer circumference of the bushings 16. The sprocket 6 may be engaged with the chain 11 by inserting the involute tooth profile of the sprocket 6 between adjacent rollers of the chain 11.

[0072] In this embodiment, the sprocket 6 had an involute tooth profile, but it is not limited to this embodiment. The sprocket 6 may have a tooth profile other than an involute tooth profile. Examples of tooth profiles other than an involute tooth profile include cycloidal tooth profiles.

[0073] In this embodiment, the sprocket 6 had 16 involute tooth profiles, but is not limited to this configuration. The sprocket 6 may have an even number of involute tooth profiles other than 16. The sprocket 6 may also have an odd number of involute tooth profiles. Even when the sprocket 6 has an odd number of involute tooth profiles, the center of the bushing 16 that meshes with the sprocket 6 in the first straight guide section 21 is positioned on the imaginary line S1, similar to the configuration shown in Figure 11. When the sprocket 6 rotates counterclockwise from this state, the bushing 16 moves along the inner circumferential surface 21a of the first straight guide section 21, the inner circumferential surface 23a of the curved guide section 23, and the inner circumferential surface 22a of the second straight guide section 22. After that, the bushing 16 meshes with the sprocket 6 again on the imaginary line S1 of the second straight guide section 22. The movement path of the bushing 16 at this time is defined as the imaginary line S3. The length of the virtual line S3 is preferably an integer multiple of L2.

[0074] In this embodiment, the chain drive device 1 had a motor 2 as a drive source, but it is not limited to this configuration. The drive source may be something other than a motor 2. For example, the drive source may be an internal combustion engine.

[0075] The slide table 5 in this embodiment may be omitted. That is, the chain 11 may be directly connected to the movable body. In this embodiment, the first straight guide section 21, the curved guide section 23, and the second straight guide section 22 extended along the horizontal direction, but the embodiment is not limited to this. The first straight guide section 21, the curved guide section 23, and the second straight guide section 22 may be on the same plane as each other and extend in any direction other than the water flow direction. For example, they may extend along the vertical direction, or they may extend at a slight inclination with respect to the horizontal direction. [Explanation of Symbols]

[0076] 1... Chain drive unit, 2... Motor, 3... Drive unit, 4... Guide rail, 5... Slide table, 6... Sprocket, 7... Case, 11... Chain, 12... Inner link, 13... Outer link, 16... Bushing (shaft member), 21... First straight guide section, 22... Second straight guide section, 23... Curved guide section, 24... First opening, 25... Second opening, 26... Connecting section.

Claims

1. Sprocket and A case in which the sprocket is housed, A chain drive device comprising a chain configured to mesh with the sprocket, thereby enabling it to move forward and backward from the case in conjunction with the rotation of the sprocket, The aforementioned case is, The first opening through which the chain is inserted, A first linear guide portion extends linearly from the first opening into the case, A curved guide portion extends in a curved manner within the case, continuous with the first straight guide portion, A second straight guide portion extends linearly within the case, continuous with the curved guide portion, It has a second opening through which the chain is inserted, continuous with the second linear guide portion, The first linear guide portion and the second linear guide portion extend parallel to each other and have connecting portions on their opposing inner circumferential surfaces. The sprocket is positioned within the connecting portion. The chain consists of multiple inner links and multiple outer links arranged alternately in a series direction, and is rotatably connected to each other via multiple shaft members. In the chain, the sprockets mesh between adjacent shaft members in the first straight guide section, and also in the second straight guide section beyond the curved guide section, the sprockets mesh between adjacent shaft members. Let the imaginary line S1 be an imaginary line that passes through the center P1 of the sprocket and extends in a direction perpendicular to the direction in which the first linear guide portion and the second linear guide portion extend. The boundary between the inner surface of the curved guide portion and the inner surface of the first straight guide portion is defined as boundary portion P2. The boundary between the inner surface of the curved guide portion and the inner surface of the second straight guide portion is defined as boundary portion P3. A virtual line extends through the boundary portion P2 in a direction perpendicular to the direction in which the first linear guide portion and the second linear guide portion extend, Comparing virtual lines extending through the boundary P3 in a direction perpendicular to the direction in which the first and second linear guide sections extend, the virtual line closer to the virtual line S1 is defined as virtual line S2. Let L1 be the distance between the virtual line S1 and the virtual line S2. If the pitch of the multiple shaft members of the chain is L2, A chain drive device characterized in that L1 and L2 satisfy the following relationship (1). [Math 1]

2. If, among the multiple shaft members of the chain, the center of the shaft member meshed with the sprocket in the first straight guide section is located on the imaginary line S1, and then the shaft member moves along the inner circumferential surface of the first straight guide section, the inner circumferential surface of the curved guide section, and the inner circumferential surface of the second straight guide section, and the movement path of the shaft member when it re-meets the sprocket on the imaginary line S1 of the second straight guide section is defined as the imaginary line S3, then The chain drive device according to claim 1, wherein the length of the virtual line S3 is an integer multiple of the L2.

3. The chain drive device according to claim 1, wherein the chain is bendable on one side in the direction intersecting the series direction, but not on the other side in the direction intersecting the series direction.

4. The chain drive device according to claim 1, wherein the sprocket has an involute tooth profile.

5. The chain drive device according to claim 1, wherein the first straight guide portion, the curved guide portion, and the second straight guide portion extend along the horizontal direction.

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