Flexible timing belt and device

Abstract

To provide a flexible timing belt that can be arranged in a three-dimensional manner while maintaining preferable drive transmission property, and to provide a device.SOLUTION: A flexible timing belt 1 capable of transmitting power from an input shaft side pulley 22 to an output shaft side pulley 23 is constituted of: a core wire 2; and a plurality of teeth 3 arranged toward a longitudinal direction of the core wire 2. The tooth 3 is made of a soft material and formed so as to project in at least two axial directions (such as X-axis direction and Y-axis direction) intersecting relative to the core wire 2, whereby the flexible timing belt allows an input shaft and an output shaft to be arranged in a three-dimensional manner while maintaining preferable drive transmission property.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flexible timing belt and apparatus for transmitting power from an input shaft to an output shaft. [Background technology]

[0002] Conventionally, one example of a power transmission member that is stretched across an input shaft and an output shaft to transmit power from the input shaft to the output shaft is a stainless steel wire rope that transmits driving force from a drive motor to multiple photosensitive drums in an image forming device to rotate them (see, for example, Patent Document 1).

[0003] Another example of a power transmission member is a toothed timing belt that is stretched between a drive pulley driven by a motor and a driven pulley, to which the carriage is fixed, in a printer carriage drive system in which the carriage can move back and forth within a certain range along a guide (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-270705 A (page 4, figure 1) [Patent Document 2] JP-A-10-159907 (page 3, figures 1-3) Summary of the Invention [Problem to be solved by the invention]

[0005] The wire rope described in Patent Document 1 above has a simple structure, allowing its drive mechanism to be designed relatively freely and compactly, and force can be easily transmitted by utilizing the tension of the wire rope. However, there is a problem in that even slight slack in the wire rope reduces drive performance.

[0006] On the other hand, the toothed timing belt described in Patent Document 2 can transmit force relatively easily even with slight slack, but in a system in which the output shaft is inclined relative to the input shaft, smooth transmission is not possible, and a separate mechanism for changing the transmission direction is required.

[0007] The present invention has been made in view of the above problems, and has an object to provide a flexible timing belt and device that can be arranged three-dimensionally while maintaining favorable drive transmission performance. [Means for solving the problem]

[0008] In order to solve the above problems, the flexible timing belt of the present invention comprises: A flexible timing belt that transmits power from an input shaft to an output shaft, A core wire, a plurality of teeth arranged in a longitudinal direction of the core wire; The teeth are made of a soft material and are formed so as to protrude in at least two axial directions intersecting with each other relative to the core wire. According to this feature, the core wire has multiple teeth made of a soft material arranged thereon, allowing bending deformation in multiple directions, and the teeth protrude in at least two axial directions, allowing the core wire to be meshed with the intersecting teeth of a gear, pulley, etc. on the input shaft and the intersecting teeth of a gear, pulley, etc. on the output shaft without having to twist the core wire circumferentially to change the orientation of the teeth, thereby making it possible to arrange the input shaft and output shaft in three dimensions while maintaining suitable drive transmission performance.

[0009] The plurality of teeth are characterized by being composed of tooth portions and inter-tooth portions disposed between adjacent tooth portions. According to this feature, the teeth can be easily spaced apart from each other.

[0010] The tooth portion is characterized in that it is formed in a substantially rectangular shape when viewed from the side. This feature makes it possible to accommodate deformation in two orthogonal axial directions.

[0011] The tooth portion is characterized in that it is formed in a substantially circular shape when viewed from the side. This feature makes it possible to accommodate deformation in multiple axial directions.

[0012] The tooth portion is characterized in that the thickness of the tooth portion is gradually reduced toward the peripheral edge portion. According to this feature, it is possible to smoothly mesh with the teeth of the gears, pulleys, etc. on the input shaft side and the teeth of the gears, pulleys, etc. on the output shaft side.

[0013] The teeth are characterized in that they are made of silicone rubber or soft synthetic resin. According to this feature, the occurrence of contact noise with the input shaft and the output shaft can be suppressed.

[0014] In addition, the device using the flexible timing belt of the present invention is A flexible timing belt transmits power from the input shaft to the output shaft. A core wire, a plurality of teeth arranged in a longitudinal direction of the core wire; The teeth are made of a soft material and are formed so as to protrude in at least two axial directions intersecting with each other relative to the core wire. According to this feature, the core wire has multiple teeth made of a soft material arranged thereon, allowing bending deformation in multiple directions, and the teeth protrude in at least two axial directions, allowing the core wire to be meshed with the intersecting teeth of a gear, pulley, etc. on the input shaft and the intersecting teeth of a gear, pulley, etc. on the output shaft without having to twist the core wire circumferentially to change the orientation of the teeth, thereby making it possible to arrange the input shaft and output shaft in three dimensions while maintaining suitable drive transmission performance.

[0015] The device using the flexible timing belt is A pair of input shafts rotatably provided around an input rotation shaft; the output shaft is provided rotatably about an output rotation axis perpendicular to the input rotation axis; a pair of guide shafts rotatably provided around a guide rotation axis perpendicular to the input rotation shaft and the output rotation shaft; A two-axis differential joint device comprising: The flexible timing belt includes a pair of flexible timing belts each stretched from a pair of the input shafts to the output shaft via a pair of the guide shafts. This feature allows the input shaft and the output shaft to be arranged three-dimensionally. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2A is a perspective view showing a part of a flexible timing belt according to an embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along the line AA of FIG. [Diagram 2] 1(a) is a cross-sectional view taken along line BB in FIG. 1(b), and (b) and (c) are diagrams showing the state in which the toothed pulley rotates around a rotation axis in a different direction and is engaged with the toothed pulley. [Diagram 3] 1(a) and 1(b) are perspective views showing a power transmission device using a flexible timing belt according to an embodiment of the present invention. [Figure 4] 4(a) is a schematic plan view showing the configuration of the power transmission device in FIG. 3, (b) is a front view, and (c) is a plan view showing a state in which the angle of the output shaft is changed around the intersecting axis. [Diagram 5] FIG. 11 is a perspective view showing a two-shaft differential joint device using a flexible timing belt as the second embodiment. [Figure 6] FIG. 6 is a front view showing the two-axis differential joint device of FIG. 5. [Figure 7] FIG. 2A is a plan view showing the two-shaft differential joint device, and FIG. 2B is a left side view showing the two-shaft differential joint device. [Figure 8] 4(a) and 4(b) are front views of the main part showing an example of the operation of a two-shaft differential joint device. [Figure 9] 4(a) and 4(b) are front views of the main part showing an example of the operation of a two-shaft differential joint device. [Figure 10] FIG. 1A is a perspective view showing a part of a flexible timing belt as a modified example of the present invention, and FIG. 1B is a cross-sectional view taken along line CC of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flexible timing belt and an apparatus according to the present invention will now be described with reference to the accompanying drawings. EXAMPLES

[0018] A flexible timing belt according to a first embodiment of the present invention will be described with reference to Figs. 1 to 4. In the following description, the diagonally lower right side of Fig. 1(a) is the front side (front side) of the flexible timing belt, and the diagonally upper left side is the rear side (back side). Fig. 1(b) is a cross-sectional view taken along line AA in Fig. 1(a), but a horizontal cross-sectional view of Fig. 1(a) will also be considered to be the same as the cross-sectional view taken along line AA.

[0019] As shown in FIG. 1, the flexible timing belt 1 according to the first embodiment of the present invention is a power transmission member that transmits power from an input shaft to an output shaft, and is mainly composed of a core wire 2 and a plurality of teeth 3 arranged in the longitudinal direction of the core wire 2.

[0020] As shown in Figures 1(a), (b) and 2(a), the core wire 2 is formed, for example, of an ultra-high molecular weight polyethylene resin having excellent abrasion resistance, self-lubricating properties and heat resistance, and has a substantially cylindrical cross section.

[0021] In the first embodiment, the ultra-high molecular weight polyethylene resin is used as the material of the core wire 2, but the present invention is not limited to this, and other synthetic resins such as polypropylene resin and nylon resin may be used. In addition to other synthetic resin materials, materials other than synthetic resins such as stainless steel may be used.

[0022] The teeth 3 are made of silicone rubber, which is an example of a soft material, and are composed of tooth portions 4 that can mesh with teeth of an input shaft, an output shaft, etc., and inter-tooth portions 5 that are arranged between adjacent tooth portions 4,4.

[0023] In this embodiment 1, the material of the teeth 3 is silicone rubber, which has excellent heat resistance and weather resistance and a hardness (unit: Shore a) of "40 to 70", but the material is not limited to silicone rubber as long as it is a soft material, and rubber with a lower hardness than silicone rubber, such as butyl rubber or ethylene rubber with a hardness (unit: Shore a) of "65", may be used. Also, rubber or soft synthetic resin with a lower or higher hardness than silicone rubber may be used.

[0024] The tooth portion 4 is formed in a plate shape that is substantially square in side view, and the core wire 2 is disposed and fixed at the center. The core wire 2 is inserted at the center of the tooth portion 4, but is not limited to this. The vertical side dimension L1 and the horizontal side dimension L2 are the same (L1=L2), and the vertical side dimension L1 and the horizontal side dimension L2 are longer than the diameter dimension R1 of the core wire 2 (L1>R1, L2>R1). The four corners C are formed in a curved shape in side view.

[0025] The tooth portion 4 is formed so that the plate thickness dimension L3 gradually decreases from the peripheral portion of the intertooth portion 5 toward the peripheral portion of the tooth portion 4. Specifically, the left and right side surfaces 4a, 4a of the tooth portion 4 are inclined in a generally curved shape so as to approach each other toward the peripheral portion, so that the tooth portion 4 is formed in a tapered shape near the peripheral portion.

[0026] As shown in FIG. 2(a), the toothed portion 4 is formed to protrude in an X-axis direction S1 (e.g., front-rear direction) and a Y-axis direction S2 (e.g., up-down direction) perpendicular to the core wire 2 at the center position. In other words, the toothed portion 4 is formed above, below, left, and right of the core wire 2. Thus, as shown in FIG. 2(b), the upper side of the toothed portion 4 can be meshed with teeth 10b of a toothed pulley 10 (hereinafter, "toothed pulley" will be simply referred to as "pulley") that rotates about a rotation shaft 10a that faces the X-axis direction S1, and as shown in FIG. 2(c), the front side of the toothed portion 4 can be meshed with teeth 11b of a pulley 11 that rotates about a rotation shaft 11a that faces the Y-axis direction S2.

[0027] Although not shown, by disposing the pulley 10 downward, the lower side of the toothed portion 4 can be meshed with the teeth 10b of the pulley 10. Also, by disposing the pulley 10 forward, the rear side of the toothed portion 4 can be meshed with the teeth 11b of the pulley 11.

[0028] As shown in Figs. 1(a), (b) and 2(a), the intertooth portion 5 is formed in a cylindrical shape, with the core wire 2 inserted at the center. The diameter dimension R2 is longer than the diameter dimension R1 of the core wire 2, but shorter than the vertical side dimension L1 and horizontal side dimension L2 of the tooth portion 4 (L1>R2>R1, L2>R2>R1). The thickness dimension L5 of the intertooth portion 5 is shorter than the thickness dimension L3 of the tooth portion 4 (L5 <L3)。

[0029] In this manner, by providing the inter-tooth portion 5 which is smaller than the tooth portion 4, the adjacent tooth portions 4, 4 are spaced apart from each other and the spaces between the tooth portions 4, 4 on the circumferential surface of the core wire 2 are covered, thereby preventing damage or cutting of the core wire 2. The inter-tooth portion 5 does not have to be cylindrical and may be formed in a square tube shape.

[0030] The flexible timing belt 1 is composed of a cylindrical core wire 2 made of ultra-high molecular weight polyethylene resin and teeth 3 (tooth portion 4 and inter-tooth portion 5) made of silicone rubber which is softer than the ultra-high molecular weight polyethylene resin core wire 2, and thus has flexibility allowing bending at least in the X-axis direction S1 and the Y-axis direction S2. The flexible timing belt 1 also has teeth portions 4 which protrude from the core wire 2 at least in the X-axis direction S1 and the Y-axis direction S2.

[0031] In this embodiment 1, both ends of one core wire 2 are bonded with an adhesive to form an endless shape (loop shape), and silicone rubber is injected into a mold in which the core wire 2 is placed to form the teeth 3, but the core wire 2 and the teeth 3 may be integrally formed by a 3D printer or the like, or the teeth 3 may be formed by cutting on the outer circumferential surface of a soft material in which the core wire 2 is embedded. Also, by integrally forming the teeth 3 consisting of the tooth portion 4 and the inter-tooth portion 5 from silicone rubber as described above, it is possible to suppress excessive deformation, such as the tooth portion 4 falling significantly toward the base side when meshing with the teeth of a pulley.

[0032] Next, a power transmission device 20 to which the flexible timing belt 1 is applied will be described with reference to Fig. 3 and Fig. 4. Fig. 3 (a) and (b) are perspective views showing a power transmission device using the flexible timing belt of this embodiment 1, and Fig. 4 (a) is a schematic plan view showing the configuration of the power transmission device of Fig. 3, (b) is a front view, and (c) is a plan view showing a state where the angle is changed.

[0033] 3 and 4, the power transmission device 20 is mainly composed of a motor 21 which is a drive source, an input shaft side pulley 22 which is rotated by the motor 21, an output shaft side pulley 23 which is rotated following the input shaft side pulley 22, an intermediate pulley 24 which is provided between the input shaft side pulley 22 and the output shaft side pulley 23, and four guide pulleys 25. The input shaft side pulley 22, the output shaft side pulley 23, the intermediate pulley 24, and the guide pulley 25 are provided on their circumferential surfaces with a plurality of teeth (e.g., 40 teeth, not shown) which can mesh with the toothed portion 4 of the flexible timing belt 1.

[0034] The input shaft side pulley 22 and the output shaft side pulley 23 are provided rotatably about a rotation axis facing the X-axis direction S1 (front-rear direction), while the intermediate pulley 24 and the guide pulley 25 are provided rotatably about a rotation axis facing the Y-axis direction S2 (up-down direction). The output shaft side pulley 23 is supported rotatably in the horizontal direction about a rotation axis (not shown) concentric with the rotation axis of the intermediate pulley 24, and is rotatable within a range of 180 degrees, 90 degrees forward (θ=90 degrees) and -90 degrees backward (θ=-90 degrees), based on a state in which the rotation axes of the input shaft side pulley 22 and the output shaft side pulley 23 are parallel (see FIG. 4(a)), that is, a state in which the rotation angle θ of the output shaft side pulley 23 with respect to the input shaft side pulley 22 is 0 degrees (see FIG. 4(c)). Even if the rotation angle θ changes within the range of 180 degrees, the path length of the flexible timing belt 1 is maintained constant.

[0035] The flexible timing belt 1 is formed in an endless shape (loop shape) and is hung between the input shaft side pulley 22 and the output shaft side pulley 23 (see Figure 4 (b)). Between the input shaft side pulley 22 and the output shaft side pulley 23, the upper portion is hung around the upper front side of the intermediate pulley 24 by two guide pulleys 25, 25, and the lower portion is hung around the lower back side of the intermediate pulley 24 by two guide pulleys 25, 25.

[0036] In this way, in the flexible timing belt 1, the upper and lower sides of the tooth portion 4 mesh with the input shaft side pulley 22 and the output shaft side pulley 23, which can rotate around a rotation axis facing the X-axis direction S1 (see Figure 4(b)), and the front and rear sides of the tooth portion 4 mesh with the intermediate pulley 24 and the guide pulley 25, which can rotate around a rotation axis facing the Y-axis direction S2 (see Figure 4(c)).

[0037] Therefore, the flexible timing belt 1 has teeth 3 made of silicone rubber, and the tooth portion 4 has upper and lower protrusions that mesh with the input shaft side pulley 22 and the output shaft side pulley 23, and front and rear protrusions that mesh with the intermediate pulley 24 and the guide pulley 25. In other words, the flexible timing belt 1 has flexibility like a wire, and can be meshed with pulleys whose rotation axes intersect without changing the orientation of the teeth by twisting the core wire 2 in the circumferential direction between the input shaft side pulley 22 and the output shaft side pulley 23, and the intermediate pulley 24 and the guide pulley 25.

[0038] Furthermore, even when the output shaft side pulley 23 is rotated horizontally within a range of rotation angle θ around a rotation axis (not shown) that is concentric with the rotation axis of the intermediate pulley 24, the rotation force of the input shaft side pulley 22 can be suitably transmitted to the output shaft side pulley 23 regardless of the rotation angle. Therefore, even when the intermediate pulley 24 and the guide pulley 25, which have rotation axes intersecting with the input shaft side pulley 22 and the output shaft side pulley 23, are present between the input shaft side pulley 22 and the output shaft side pulley 23, the flexible timing belt 1 can transmit power from the input shaft side pulley 22 to the output shaft side pulley 23 without providing a separate mechanism for changing the rotation direction, etc.

[0039] In the first embodiment, all of the pulleys, including the input shaft side pulley 22, the output shaft side pulley 23, the intermediate pulley 24, and the guide pulley 25, have a plurality of teeth on their circumferential surfaces that can mesh with the toothed portion 4 of the flexible timing belt 1, and the intermediate pulley 24, which serves as the center of rotation, is also toothed, making it easy to change the angle. Furthermore, the guide pulley 25 is also toothed, making it easy to change the angle. Note that as long as at least the input shaft side pulley 22 and the output shaft side pulley 23 are toothed pulleys, the other pulleys may be pulleys without teeth.

[0040] Although no detailed explanation will be given, the applicant verified the drive transmission performance of the above-mentioned power transmission device 20, in which an input shaft side pulley 22, an output shaft side pulley 23, and an intermediate pulley 24 with a different axial direction are included in the path of the flexible timing belt 1, and found that when the input shaft side pulley 22 was rotated at a constant angular velocity while the output shaft side pulley 23 was moved horizontally within a range of rotation angle θ by 30 degrees each time around a rotation axis (not shown) concentric with the rotation axis of the intermediate pulley 24, the same drive transmission performance was observed regardless of the rotation angle of the output shaft side pulley 23. EXAMPLES

[0041] A two-shaft differential joint device as an example of a device using a flexible timing belt according to a second embodiment of the present invention will be described with reference to Figs. 5 to 9. Fig. 5 is a perspective view showing a two-shaft differential joint device using a flexible timing belt as the second embodiment, Fig. 6 is a front view showing the two-shaft differential joint device of Fig. 5, Fig. 7 (a) is a plan view showing the two-shaft differential joint device, Fig. 7 (b) is a left side view showing the two-shaft differential joint device, Fig. 8 (a) and (b) are front views of the main part showing an operation example of the two-shaft differential joint device, and Fig. 9 (a) and (b) are front views of the main part showing an operation example of the two-shaft differential joint device. In the following description, the diagonally lower right side of Fig. 5 will be described as the front side (front side) of the two-shaft differential joint device using a flexible timing belt, and the diagonally upper left side will be described as the rear side (rear side).

[0042] As shown in Figures 5 to 7(a) and (b), the two-shaft differential joint device 50 has motors 51a, 51b as drive sources, left and right drive pulleys 52a, 52b rotated by the motors 51a, 51b, left and right input shaft pulleys 53a, 53b and an upper output shaft pulley 54 which rotate following the drive pulleys 52a, 52b, left and right intermediate pulleys 55a, 55b provided between the drive pulleys 52a, 52b and the input shaft pulleys 53a, 53b, and left front and rear guide pulleys 56, 56 and right front and rear guide pulleys 57, 57 provided between the input shaft pulleys 53a, 53b and the output shaft pulley 54.

[0043] The peripheral surfaces of the drive pulleys 52a, 52b, the input shaft side pulleys 53a, 53b, the output shaft side pulley 54, and the intermediate pulleys 55a, 55b are provided with a plurality of teeth (not shown) that can mesh with the tooth portions 4 of the flexible timing belts 1A, 1B and the tooth portions (not shown) of the timing belts 61a, 61b, 62a, 62b described later.

[0044] The output rotation axis of the output shaft pulley 54 is perpendicular to the input rotation axis of the input shaft pulleys 53a and 53b. In addition, the guide rotation axes of the guide pulleys 56, 56, 57, and 57 are perpendicular to the output rotation axis of the output shaft pulley 54 and the input rotation axis of the input shaft pulleys 53a and 53b.

[0045] 5, the description will be given assuming that the input rotation axes of the drive pulleys 52a, 52b, the input shaft side pulleys 53a, 53b and the rotation axes of the intermediate pulleys 55a, 55b face the X-axis direction S11 (left-right direction), the output rotation axis of the output shaft side pulley 54 faces the Y-axis direction S12 (up-down direction), and the guide rotation axes of the guide pulleys 56, 56, 57, 57 face the Z-axis direction S13 (front-back direction). Note that the left guide pulleys 56, 56 are disposed slightly above the right guide pulleys 57, 57 (see FIG. 6).

[0046] In addition, the output shaft side pulley 54 is supported so as to be rotatable in the front-rear direction around the input rotation shaft facing the X-axis direction S11 (left-right direction), and as shown in Figure 7 (b), can be rotated within a range of approximately 180 degrees, that is, 90 degrees forward and -90 degrees rearward, based on the state in which the output rotation shaft facing the Y-axis direction S12 (up-down direction) faces in the up-down direction.

[0047] Each of the intermediate pulleys 55a, 55b has a speed reduction function and is formed by integrating a large diameter pulley and a small diameter pulley. Timing belts 61a, 61b are stretched between the drive pulleys 52a, 52b and the large diameter pulleys of the intermediate pulleys 55a, 55b, and timing belts 62a, 62b are stretched between the small diameter pulleys of the intermediate pulleys 55a, 55b and the input shaft side pulleys 53a, 53b.

[0048] Each of the flexible timing belts 1A, 1B is formed in an endless shape (loop shape) and is configured similarly to the flexible timing belt 1 of the first embodiment, so detailed description will be omitted here. The flexible timing belt 1A is stretched between the left input shaft side pulley 53a and the output shaft side pulley 54 via guide pulleys 56, 56, and the flexible timing belt 1B is stretched between the right input shaft side pulley 53b and the output shaft side pulley 54 via guide pulleys 57, 57.

[0049] Specifically, the portion of the flexible timing belt 1A below the guide pulleys 56, 56 is hung over the input shaft pulley 53a, and the portion to the right of the guide pulleys 56, 56 is hung over the upper part of the output shaft pulley 54. The portion of the flexible timing belt 1B below the guide pulleys 56, 56 is hung over the input shaft pulley 53b, and the portion to the left of the guide pulleys 56, 56 is hung over the lower part of the output shaft pulley 54. The flexible timing belts 1A, 1B are configured to maintain a constant path length even if the output shaft pulley 54 rotates in the front-to-rear direction about the input rotation axis facing the X-axis direction S11 (left-right direction).

[0050] In this way, in the flexible timing belts 1A, 1B, the rear sides of the toothed portion 4 mesh with the input shaft side pulleys 53a, 53b rotatable about an input rotation shaft facing the X-axis direction S11 and the output shaft side pulley 54 rotatable about an output rotation shaft facing the Y-axis direction S12 (up and down direction), while the lower sides of the toothed portion 4 abut against the guide pulleys 56, 56, 57, 57 rotatable about a guide rotation shaft facing the Z-axis direction S13. Also, while the input shaft side pulleys 53a, 53b move in the Y-axis direction S12 on the front and rear sides, the guide pulleys 56, 56, 57, 57 change direction, so that the output shaft side pulley 54 moves in the X-axis direction S11 on the front and rear sides.

[0051] In other words, the side surface 4a of the tooth portion 4 of the flexible timing belts 1A, 1B is generally rectangular when viewed from the side as described in the first embodiment, and therefore meshes with the input shaft side pulleys 53a, 53b and the output shaft side pulley 54 at points perpendicular to each other, resulting in a large meshing allowance, and improved drive transmission performance.

[0052] The two-shaft differential joint device 50 also includes a rotary encoder 41 capable of detecting the rotation angle of input shaft-side pulleys 53a and 53b fixed to an input rotating shaft facing the X-axis direction S11, a rotary encoder 42 capable of detecting the rotation angle of an output shaft-side pulley 54 fixed to an output rotating shaft facing the Y-axis direction S12, a pulley 43 fixed to the input rotating shaft facing the X-axis direction S11, a pulley 44 fixed to the rotating shaft of the rotary encoder 41, a pulley 45 provided between the pulleys 43 and 44, a timing belt 46 stretched around the pulleys 43 and 45, and a timing belt 47 stretched around the pulleys 44 and 45. The rotary encoders 41 and 42, the pulleys 43, 44 and 45, and the timing belts 46 and 47 are not necessarily required to be provided.

[0053] Next, an example of the operation of the two-shaft differential joint device 50 will be described with reference to FIGS.

[0054] As shown in FIG. 8(a), when both left and right input shaft pulleys 53a, 53b rotate 180 degrees in the forward direction (clockwise when viewed from the left side) around the input rotation axis facing the X-axis direction S11 (see thick white arrow), the flexible timing belts 1A, 1B meshing with the output shaft pulley 54 attempt to move in opposite directions, so that the output shaft pulley 54 rotates a predetermined angle of approximately 180 degrees in the forward direction around the input rotation axis facing the X-axis direction S11 without rotating around the output rotation axis facing the Y-axis direction S12 (see thick black arrow).

[0055] As shown in FIG. 8(b), when the left input shaft pulley 53a rotates 180 degrees (-180 degrees) in the reverse direction (counterclockwise when viewed from the left side) around the input rotation shaft facing the X-axis direction S11, while the right input shaft pulley 53b rotates 180 degrees in the forward direction around the input rotation shaft facing the X-axis direction S11 (see thick white arrow), the flexible timing belts 1A, 1B meshing with the output shaft pulley 54 each attempt to move to the right when viewed from the front, and as a result, the output shaft pulley 54 rotates a predetermined angle of approximately 180 degrees in the forward direction around the output rotation shaft facing the Y-axis direction S12, without rotating around the input rotation shaft facing the X-axis direction S11 (see thick black arrow).

[0056] As shown in FIG. 9(a), when the left input shaft pulley 53a rotates 90 degrees (-90 degrees) in the reverse direction around the input rotation shaft facing the X-axis direction S11 while the right input shaft pulley 53b rotates 180 degrees in the forward direction around the input rotation shaft facing the X-axis direction S11 (see thick white arrow), the flexible timing belts 1A, 1B meshing with the output shaft pulley 54 each move to the right when viewed from the front. However, because the rotation angles of the input shaft pulleys 53a, 53b are different, the output shaft pulley 54 rotates a predetermined angle of approximately 135 degrees in the forward direction around the input rotation shaft facing the X-axis direction S11 and rotates a predetermined angle of approximately 90 degrees in the forward direction around the output rotation shaft facing the Y-axis direction S12 (see thick black arrow).

[0057] As shown in FIG. 9(b), when the left input shaft pulley 53a rotates 90 degrees in the forward direction around the input rotation shaft facing in the X-axis direction S11, while the right input shaft pulley 53b rotates 180 degrees in the forward direction around the input rotation shaft facing in the X-axis direction S11 (see thick white arrow), the flexible timing belts 1A, 1B meshing with the output shaft pulley 54 move in opposite directions when viewed from the front, but because the rotation angles of the input shaft pulleys 53a, 53b are different, the output shaft pulley 54 rotates a predetermined angle of approximately 90 degrees in the forward direction around the input rotation shaft facing in the X-axis direction S11, and rotates a predetermined angle of approximately 135 degrees in the forward direction around the output rotation shaft facing in the Y-axis direction S12 (see thick black arrow).

[0058] In this way, the driving force is transmitted from the motors 51a, 51b to the input shaft side pulleys 53a, 53b via the timing belts 61a, 61b, 62a, 62b, and from there, via the flexible timing belts 1A, 1B and the guide pulleys 56, 56, 57, 57 for changing direction, to the output shaft side pulley 54, thereby functioning as a differential mechanism. By using this differential mechanism, it is possible to realize a rotation movement only in the X-axis direction S11 or Y-axis direction S12, or a rotation movement that combines the X-axis direction S11 and the Y-axis direction S12, simply by changing the number of rotations of the motors 51a, 51b transmitted to the input shaft side pulleys 53a, 53b, and it is possible to combine the output around the desired rotation axis depending on the situation.

[0059] Furthermore, the flexible timing belts 1A, 1B have teeth 3 made of soft synthetic resin, and the tooth portion 4 has at least a rear protruding portion that meshes with the input shaft side pulleys 53a, 53b and the output shaft side pulley 54, and a lower protruding portion that meshes with the guide pulleys 56, 56, 57, 57. In other words, the flexible timing belts 1A, 1B have flexibility like a wire, and can be meshed with pulleys whose rotation axes intersect without changing the direction of the teeth by twisting the core wire 2 (see FIG. 1) in the circumferential direction between the input shaft side pulleys 53a, 53b and the output shaft side pulley 54.

[0060] Furthermore, even if there are guide pulleys 56, 56, 57, 57 having rotation axes that intersect with the input shaft side pulleys 53a, 53b and the output shaft side pulley 54 between them, power can be transmitted from the input shaft side pulleys 53a, 53b to the output shaft side pulley 54 by the flexible timing belts 1A, 1B without the need for a separate mechanism for changing the direction of rotation.

[0061] In the second embodiment, the input shaft side pulleys 53a, 53b and the output shaft side pulley 54 are provided on their circumferential surfaces with a plurality of teeth that can mesh with the toothed portion 4 of the flexible timing belt 1, making it easy to change the angle. Note that as long as at least the input shaft side pulleys 53a, 53b and the output shaft side pulley 54 are toothed pulleys, the other pulleys may be pulleys without teeth.

[0062] Although no detailed explanation will be given, the applicant verified the drive transmission performance in the above-mentioned two-shaft differential joint device 50 in which the input shaft side pulleys 53a, 53b, the output shaft side pulley 54 and the guide pulleys 56, 56, 57, 57 are included in the path of the flexible timing belts 1A, 1B, and found that the angular velocity was transmitted correctly.

[0063] (Action and effect) As described above, the flexible timing belts 1, 1A, 1B as embodiments 1 and 2 of the present invention are capable of transmitting power from the input shaft side pulley 22, 53a, 53b (input shaft) to the output shaft side pulley 23, 54 (output shaft), and are composed of a core wire 2 and a plurality of teeth 3 arranged in the longitudinal direction of the core wire 2, the teeth 3 being made of a soft material such as silicone rubber or soft synthetic resin, and formed to protrude in at least two axial directions that intersect with the core wire 2 (for example, the X-axis directions S1, S11 and the Y-axis directions S2, S12).

[0064] According to this, multiple teeth 3 made of soft material are arranged on the core wire 2, allowing bending deformation in multiple directions, and since the teeth 3 protrude in at least two axial directions, the teeth 3 of the flexible timing belt 1 can be meshed with the teeth of the input shaft side pulley 22, 53a, 53b (input shaft) and the teeth of the output shaft side pulley 23, 54 (output shaft) that intersect with each other without twisting the core wire 2 circumferentially to change the orientation of the teeth 3.This makes it possible to three-dimensionally arrange the input shaft side pulley 22, 53a, 53b (input shaft) and the output shaft side pulley 23, 54 (output shaft) while maintaining suitable drive transmission performance.

[0065] Furthermore, since the multiple teeth 3 are composed of tooth portions 4 and inter-tooth portions 5 arranged between the tooth portions 4, 4, the tooth portions 4 can be easily spaced apart.

[0066] In addition, in this embodiment 1, an example is given of a form in which the inter-tooth portion 5 is arranged between the tooth portions 4, 4, but the present invention is not limited to this, and as long as the flexible timing belt 1 has at least a core wire 2 and a tooth portion 4, the space between the tooth portions 4, 4 on the circumferential surface of the core wire 2 does not necessarily have to be covered by the inter-tooth portion 5.

[0067] Moreover, the tooth portion 4 is formed in a generally rectangular shape when viewed from the side, and is therefore capable of responding to deformation in two orthogonal axial directions.

[0068] Moreover, the teeth portion 4 is formed so that the plate thickness dimension L3 gradually decreases toward the peripheral edge portion, thereby enabling the teeth portion 4 to smoothly mesh with the input shaft and the output shaft.

[0069] In addition, the tooth portion 4 is made of silicone rubber or soft synthetic resin, which has excellent heat resistance and weather resistance, allowing the flexible timing belt 1 to rotate infinitely while suppressing the generation of contact noise with the input shaft and output shaft.

[0070] In addition, the teeth 3 are preferably softer than the core wire 2. This makes it easier to make the teeth 3 deformable while maintaining the overall shape of the flexible timing belt 1 when driven. Furthermore, the teeth 3 are preferably softer than the teeth of the toothed pulleys on the input shaft side and the output shaft side. This makes it easier to mesh with the teeth of the toothed pulleys by deforming to match them, and also improves noise reduction.

[0071] In addition, in the power transmission device 20 using the flexible timing belt 1, multiple teeth 3 made of a soft material are arranged on the core wire 2, allowing bending deformation in multiple directions, and because the teeth 3 protrude in at least two axial directions, the teeth 3 of the flexible timing belt 1 can be meshed with the teeth of the input shaft side pulley 22 (input shaft) and the teeth of the output shaft side pulley 23 (output shaft) that intersect with each other without twisting the core wire 2 circumferentially to change the orientation of the teeth 3.This makes it possible to three-dimensionally arrange the input shaft side pulley 22 (input shaft) and the output shaft side pulley 23 (output shaft) while maintaining suitable drive transmission performance.

[0072] In addition, in the two-axis differential joint device 50 using the flexible timing belts 1A, 1B, multiple teeth 3 made of a soft material are arranged on the core wire 2, allowing bending deformation in multiple directions, and since the teeth 3 protrude in at least two axial directions, the teeth 3 of the flexible timing belts 1A, 1B can be meshed with the teeth of the input shaft side pulleys 53a, 53b (input shaft) and the teeth of the output shaft side pulley 54 (output shaft) that intersect with each other without twisting the core wire 2 circumferentially to change the orientation of the teeth 3.This makes it possible to three-dimensionally arrange the input shaft side pulleys 53a, 53b (input shaft), the output shaft side pulley 54 (output shaft), and the guide pulleys 56, 56, 57, 57, etc. while maintaining suitable drive transmission performance.

[0073] Further, the two-shaft differential joint device 50 using the flexible timing belts 1A, 1B includes a pair of input shaft side pulleys 53a, 53b (input shafts) rotatably provided around an input rotation shaft facing the X-axis direction S11, an output shaft side pulley 54 (output shaft) rotatably provided around an output rotation shaft facing the Y-axis direction S12 perpendicular to the X-axis direction S11, and a pair of guide pulleys 56, 56, 57, 57 (guide shafts) rotatably provided around a guide rotation shaft facing the Z-axis direction S13 perpendicular to the X-axis direction S11 and the Y-axis direction S12. The pair of flexible timing belts 1A, 1B are stretched from each of the pair of input shaft side pulleys 53a, 53b to the output shaft side pulley 54 via each of the pair of guide pulleys 56, 56, 57, 57, thereby enabling a three-dimensional arrangement of the input shaft and the output shaft.

[0074] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0075] For example, in the first and second embodiments, the tooth portion 4 is formed in a substantially rectangular shape in side view and is configured to be able to accommodate deformation in the X-axis direction S1 and the Y-axis direction S2, but the present invention is not limited to this, and for example, as in a flexible timing belt 31 as a modified example of the present invention shown in Figures 10(a) and (b), the tooth portion 34 may have a side surface 34a formed in a substantially circular shape in side view. This allows the tooth portion 34 to accommodate deformation in the XY-axis S3 direction in addition to the X-axis S1 and Y-axis S2, and therefore allows the tooth portion 34 to accommodate deformation in multiple axial directions, such as the diagonal up-down direction and the diagonal front-back direction in addition to the up-down direction and the front-back direction, thereby enabling a three-dimensional arrangement.

[0076] Furthermore, the shape of the teeth in side view is not limited to the above-mentioned quadrangular or circular shape, and may be, for example, a vertically elongated rectangular shape that protrudes in only one axial direction (e.g., up and down) relative to the core wire 2, a substantially triangular shape that protrudes in only three axial directions (e.g., upward, diagonally downward left, and diagonally downward right) relative to the core wire 2, or a polygonal shape that protrudes in five axial directions relative to the core wire 2. Also, it may be a substantially cross shape in side view, etc.

[0077] In the above-mentioned first and second embodiments, the tooth portion 4 and the interdental portion 5 constituting the teeth 3 are integrally formed from silicone rubber or soft synthetic resin, but the present invention is not limited to this, and the tooth portion 4 and the interdental portion 5 may be formed from different materials. Also, the tooth portion 4 and the interdental portion 5 may be formed separately.

[0078] In the first and second embodiments, the flexible timing belt 1 has the core 2 made of ultra-high molecular weight polyethylene resin and the teeth 3 made of silicone rubber or soft synthetic resin integrally formed therewith, but the present invention is not limited to this, and the core 2 and the teeth 3 may be made of the same material. Also, the core 2, the tooth portion 4, and the inter-tooth portion 5 may all be integrally formed of the same material. Furthermore, the teeth of the toothed pulleys on the input shaft side and the output shaft side may be made of the same material as the teeth 3 of the flexible timing belt 1, or may be made of a different material, but it is preferable that the teeth are harder than the teeth 3 of the flexible timing belt 1.

[0079] In addition, in the above-mentioned first and second embodiments, the flexible timing belt 1 is formed in an endless shape (loop shape) and used, but the present invention is not limited to this, and the flexible timing belt 1 may be used in an endless state. [Industrial Applicability]

[0080] The flexible timing belt of the present invention is applicable to devices that transmit power. For example, in the field of robotics, it can be used in robots that transmit power remotely using end effectors, but it can also be applied to general devices that transmit power in the mechanical field, such as image forming devices and printer carriages described in the prior art section. [Explanation of symbols]

[0081] 1,1A,1B Flexible timing belt 2-core wire 3 Teeth 4 Teeth 4a side 5 Interdental area 10,11 Toothed pulley (input shaft, output shaft) 10a, 11a Rotating shaft (input shaft, output shaft) 10b,11b teeth 20 Power transmission device (device using flexible timing belt) 21 Motor 22 Input shaft side pulley (input shaft) 23 Output shaft side pulley (output shaft) 24 Intermediate pulley 25 Guide pulley 31 Flexible timing belt 34 Teeth 50 2-axis differential joint device (device using flexible timing belt) 51a, 51b Motor 53a, 53b Input shaft side pulley (input shaft) 54 Output shaft side pulley (output shaft) 56,56,57,57 Guide pulley

Claims

1. A flexible timing belt that transmits power from an input shaft to an output shaft, A core wire, a plurality of teeth arranged in a longitudinal direction of the core wire; A flexible timing belt, wherein the teeth are made of a soft material and are formed so as to protrude in at least two axial directions intersecting with respect to the core wire.

2. 2. The flexible timing belt of claim 1, wherein the plurality of teeth are comprised of tooth portions and inter-tooth portions disposed between adjacent tooth portions.

3. 3. The flexible timing belt according to claim 2, wherein the teeth are formed in a generally rectangular shape when viewed from the side.

4. 3. The flexible timing belt according to claim 2, wherein the teeth are formed in a generally circular shape when viewed from the side.

5. 3. The flexible timing belt according to claim 2, wherein the tooth portion is formed so that a plate thickness dimension thereof gradually decreases toward a peripheral edge portion.

6. 3. The flexible timing belt according to claim 2, wherein the teeth are made of silicone rubber or soft synthetic resin.

7. An apparatus using the flexible timing belt according to any one of claims 1 to 6.

8. A pair of input shafts rotatably provided around an input rotation shaft; the output shaft is provided rotatably about an output rotation axis perpendicular to the input rotation axis; a pair of guide shafts rotatably provided around a guide rotation axis perpendicular to the input rotation shaft and the output rotation shaft; A two-axis differential joint device comprising:

8. The apparatus using a flexible timing belt according to claim 7, characterized in that the flexible timing belt comprises a pair of flexible timing belts stretched from each of the pair of input shafts to each of the pair of guide shafts via each of the pair of guide shafts to the output shaft.

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