Gear reducer mounting structure

Abstract

The height dimension of the gearbox mounting structure for attaching the gearbox to the mounting object is reduced. [Solution] Two mounting plates 3a and 3b are provided to clamp the reduction gear 2 in the direction of the output shaft 2b of the reduction gear. One surface 3c, 3d on each of the two mounting plates, parallel to the output shaft, is a mounting surface for attaching the reduction gear to the mounting body. A spigot hole may be formed on one of the two mounting plates to fit with a spigot projection 2e of the reduction gear, which is formed to protrude in the direction of the output shaft of the reduction gear.

Description

Technical Field

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[0001] The present invention relates to a speed reducer mounting structure.

Background Art

[0002] A speed reducer is used to reduce the rotational speed of an electric motor and obtain high torque. Patent Document 1 describes a structure in which a speed reducer is installed on a surface parallel to the output shaft by using mounting holes formed on the front and back surfaces where the output shaft of a right-angle speed reducer body protrudes, and a leg member including a base body and two leg portions erected from the base body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <00​​​​​​​​​​​​

[0007] According to the present invention, the height dimension of the gearbox mounting structure for attaching the gearbox to the mounting object can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the gearbox and L-shaped mounting plate. [Figure 2A] This is a perspective view of an electric motor and a gearbox. [Figure 2B] This is a cross-sectional view of a speed reducer. [Figure 2C] This is a diagram showing the internal structure of a gearbox. [Figure 3] A perspective view showing a gearbox mounting structure according to one embodiment. [Figure 4A] This is a perspective view showing the mounting plate on the output side of the gearbox. [Figure 4B] This is a partial cross-sectional view of the mounting plate on the output side of the gearbox. [Figure 5A] This is a perspective view showing the mounting plate on the output side of the gearbox. [Figure 5B] This is a partial cross-sectional view of the mounting plate on the output side of the gearbox. [Figure 6A] This is a perspective view showing how the mounting plate is attached to the gearbox. [Figure 6B] This is a partial cross-sectional view of the gearbox mounting structure. [Figure 7] This is a perspective view showing an example of the configuration of the drive unit for traction. [Figure 8A] This is a perspective view of the drive unit for traction. [Figure 8B] This is a side view of the drive unit for traction. [Figure 9A] This is a perspective view showing another example of a mounting plate. [Figure 9B] This is a perspective view showing the mounting plate with the additional functional components assembled. [Figure 10A] This is a perspective view showing an example of mounting the mounting plate. [Figure 10B] This is a perspective view showing another mounting example of the mounting plate. [Figure 10C]It is a perspective view showing another mounting example of the mounting plate. [Figure 11A1] It is a perspective view showing one of a pair of traveling drive units. [Figure 11A2] It is a perspective view showing the other of a pair of traveling drive units. [Figure 11B] It is a perspective view of a pair of traveling drive units.

Mode for Carrying Out the Invention

[0009] In the figures referred to below, the x-axis, y-axis, and z-axis may be shown. The orthogonal coordinate system of the three-dimensional space is a right-handed system, the xy plane is the horizontal plane, and the z-axis is vertically upward with respect to the xy plane.

[0010] <Examination>[[ID=2i]] First, the inventor of the present invention examined a speed reducer mounting structure using an L-shaped mounting plate for an offset type parallel shaft gear speed reducer with a flange surface mounting structure that is generally used. The speed reducer 2a assembled to the electric motor 1a in FIG. 1 is provided with an inro convex portion 2ae (similar to the inro convex portion 2e in FIG. 2A described later) for flange surface mounting, and mounting holes extending in the x-axis direction (similar to the mounting holes 2f in FIG. 2A described later) are provided at the four corners of the square-shaped region (flange surface) on the output side of the speed reducer centered on the inro convex portion. Using the inro convex portion 2ae and the four mounting holes, an L-shaped mounting plate 6 is attached along the upper surface of the case and the end face on the output shaft side of the speed reducer 2a. The mounting plate 6 is directly above the upper surface of the case of the speed reducer 2a and is parallel to the upper surface of the case, and has a mounting surface 6c that is attached to the bottom surface portion (not shown) of the traveling and conveying robot. Tap holes 6d for attachment to the bottom surface portion are formed in the mounting surface 6c. A wheel 5b1 of the traveling and conveying robot is fixed to the output shaft of the speed reducer 2a.'

[0011] The clearance dimension 6a1 between the mounting surface 6c and the top surface 2ga of the case of the reducer 2a is approximately 10 mm, for example. The height dimension 6b1 from the running surface of the mobile transport robot to the mounting surface 6c increases by the amount of this clearance dimension 6a1. The thickness of the portion of the L-shaped mounting plate 6 parallel to the top surface of the case of the reducer 2a must be above a certain level in order to form the tapped hole 6d, so there are limits to the method of reducing the clearance dimension 6a1 by reducing the above thickness.

[0012] As shown in Figure 1, it is difficult to reduce the height dimension of the gearbox mounting structure. When such a gearbox mounting structure is used in mobile transport robots such as AGVs and AMRs, there is a problem in that it is difficult to ensure the low profile required for such mobile transport robots.

[0013] Next, the inventors of the present invention examined the structure of the speed reducer itself. As shown in Figure 2A, a rectangular parallelepiped-shaped speed reducer 2, with its longitudinal direction in the y-axis direction, is assembled to an electric motor 1 having an output shaft pinion in the x-axis direction (reference numeral 2j1-1 in Figure 2B). The output shaft of the speed reducer 2 is also in the x-axis direction, but its position in the y-axis direction is different from that of the input section into which the output shaft pinion of the electric motor 1 is inserted. Thus, the speed reducer 2 is an offset type speed reducer in which the input section and the output shaft are offset in the y-axis direction.

[0014] On one of the end faces of the reduction gear 2 located on the positive x-axis side, the rectangular area excluding the region facing the motor 1 in the x-axis direction is the reduction gear output side region 2c. A hollow output shaft 2b extending in the x-axis direction is located approximately in the center of the reduction gear output side region 2c, and a roughly circular spigot projection 2e is provided to surround the output shaft 2b. Holes 2f penetrating in the x-axis direction are formed at the four corners of the reduction gear output side region 2c. The region facing the reduction gear output side region 2c in the x-axis direction is the reduction gear non-output side region 2d. Reference numeral 2g denotes the upper surface of the reduction gear case.

[0015] As shown in Figure 2B, the reduction gear 2 is a three-stage reduction gear. The rotation of the output shaft of the motor 1 is reduced by the first gear pair of the reduction gear 2 (a gear pair consisting of the output shaft pinion 2j1-1 of the motor 1 and gear 2j1-2 inside the reduction gear 2), the second gear pair of the reduction gear 2 (a gear pair consisting of gears 2j2-1 and 2j2-2 inside the reduction gear 2), and the third gear pair of the reduction gear 2 (a gear pair consisting of gears 2j3-1 and 2j3-2 inside the reduction gear 2), and the torque generated on the output shaft 2b of the reduction gear 2 is amplified.

[0016] In the reduction gear 2, the first, second, and third gear pairs are arranged parallel to each other in the y-axis direction. This allows the output shaft 2b of the reduction gear 2 to be positioned offset from the output shaft of the electric motor 1, and also makes it easy to make the output shaft 2b hollow. By making the output shaft 2b hollow, it can be used universally for various applications. In the case of a mobile transport robot, it is possible to freely design the shaft for assembling the wheels.

[0017] Furthermore, by increasing the size of the driven gear 2j3-2 in the third gear pair to a degree that does not interfere with the case 2k of the reduction gear 2 shown in Figure 2C, the allowable torque of the reduction gear 2 can be increased.

[0018] Note that the output shaft 2b may be solid. Although the reduction gear 2 is shown as a 3-stage reduction gear, the number of reduction stages can be any number. The reduction gear 2 is not limited to a reduction gear (flat gearhead) that utilizes the principle of a parallel-axis gear reduction gear, but may also be an orthogonal-axis gear reduction gear using hypoid gears, worm gears, face gears, etc. In this case, the input section is in the y-axis or z-axis direction, and the output shaft 2b is in the x-axis direction.

[0019] To attach such a gearbox 2 to the mounting body, one could consider machining tapped holes in the case 2k of the gearbox 2 and attaching the case 2k itself to the mounting body. However, as mentioned above, in order to make the size of the third stage driven gear 2j3-2 as large as possible, and in order to keep the overall dimensional increase of the gearbox 2 to a minimum, the wall thickness 2l of the case 2k is relatively thin. If tapped holes are machined into such a case 2k, the holes will lead to the inside of the case, which could cause problems such as leakage of lubricating grease.

[0020] Increasing the wall thickness of case 2k of reducer 2 to the point where it can be tapped would increase the overall dimensions of reducer 2. Furthermore, case 2k is often manufactured using die-casting methods with aluminum alloys, and increasing the wall thickness increases the likelihood of porosity formation, which in turn increases the risk of lubricating grease leaking through these porosity pathways. Additionally, there is the problem of having to create a dedicated case 2k with increased wall thickness.

[0021] <Embodiment> Embodiments of the present invention, made in view of the above considerations, are described below. However, the present invention is not limited to the embodiments described below.

[0022] As shown in Figure 3, two mounting plates 3a and 3b are attached to the speed reducer 2 so as to sandwich the speed reducer in the direction of the output axis. The output-side mounting plate 3a is attached to the output-side region 2c of the speed reducer 2, and the non-output-side mounting plate 3b is attached to the non-output-side region 2d. Both the output-side mounting plate 3a and the non-output-side mounting plate 3b have their vertical axis in the z-axis direction, their horizontal axis in the y-axis direction, and their thickness in the x-axis direction (the output axis direction of the speed reducer 2).

[0023] As shown in Figures 3, 4A, and 4B, the output-side mounting plate 3a is rectangular in shape with a spigot hole 3a4 formed approximately in the center, and through holes 3a1-a, 3a1-b, 3a1-c, and 3a1-d formed in the thickness direction at the four corners. On the inner circumferential surface of these four holes, a fitting portion 3a2 is formed along the axial direction towards the reducer 2, and a female threaded portion 3a3 is formed adjacent to this fitting portion 3a2 on the outer side in the thickness direction. The fitting portion 3a2 fits with the shoulder portion of the shoulder bolt, which will be described later, and the threaded portion of the shoulder bolt is fastened to the female threaded portion 3a3. On the output-side mounting surface 3c, which is perpendicular to the output-side region 2c of the reducer 2, a tapped hole 3e and a positioning pin hole 3f are machined as mounting portions to the object to be mounted.

[0024] As shown in Figures 3, 5A, and 5B, the non-output side mounting plate 3b is rectangular in shape with a hole 3b4 formed approximately in the center, and through holes 3b1-a, 3b1-b, 3b1-c, and 3b1-d formed in the thickness direction at the four corners. The inner circumferential surfaces 3b2 of these four holes fit with the shoulders of the shoulder bolts, which will be described later. Tapped holes 3e are machined into the non-output side mounting surface 3d, which is perpendicular to the non-output side region 2d of the reducer 2, as mounting parts for the object to be mounted.

[0025] The following provides a detailed explanation with specific numerical examples. However, the dimensions described below are merely examples. The output-side mounting plate 3a and the non-output-side mounting plate 3b have a y-axis dimension (horizontal dimension) W3 of 90 mm, a z-axis dimension (vertical dimension) H3 of 91 mm, and an x-axis dimension (thickness dimension) D3 of 14 mm. The fit (clearance fit) between the spigot hole 3a4 (φ50 H7 tolerance) of the output-side mounting plate 3a and the spigot protrusion 2e (φ50 h7 tolerance) of the reducer 2 makes it possible to align the center positions of both with an error (radial error) of approximately 20-30 μm on each side.

[0026] As shown in Figures 6A and 6B, the shoulder bolt (or stripper bolt) 4a has a head, a shoulder portion 4b that is not threaded, and a threaded portion 4c at its tip. The reducer 2 is sandwiched between the output-side mounting plate 3a and the non-output-side mounting plate 3b, and the four shoulder bolts 4a are passed sequentially through the holes in the non-output-side mounting plate 3b (reference numerals 3b1-a, 3b1-b, 3b1-c, and 3b1-d), the through-hole 2f (φ8.5) of the reducer 2, and the holes in the output-side mounting plate 3a (reference numerals 3a1-a, 3a1-b, 3a1-c, and 3a1-d), with the threaded portion 4c fastened to the female thread portion 3a3 (Japanese Industrial Standard M6).

[0027] The shoulder portion 4b of the shoulder bolt 4a has a tolerance of φ8e9, and the fitting portion 3b2 of the non-output side mounting plate 3b and the fitting portion 3a2 of the output side mounting plate 3a have a tolerance of φ8P7. The fitting of the shoulder bolt 4a with the fitting portions 3a2 and 3b2 makes it possible to attach the mounting plates 3a and 3b to the reducer 2 with an error of about 20 to 30 μm on each side.

[0028] While four shoulder bolts are used to provide four fitting points on each mounting plate, the design is not limited to this. Two or more shoulder bolts may be used to provide two or more fitting points on each mounting plate. Two of these fitting points can be positioned approximately diagonally opposite each other on each mounting plate, with the center in between. This increases the distance between the two fitting points compared to the case where the two fitting points are provided along the outer edge of each mounting plate, enabling more precise assembly. Specifically, mounting plates 3a and 3b can be mounted parallel to the output side region (flange surface of the reducer 2) 2c of the reducer 2, and as a result, the mounting surface 3c of mounting plate 3a and the mounting surface 3d of mounting plate 3b can be positioned on the same horizontal plane. The fitting tolerance between the output side mounting plate 3a and the non-output side mounting plate 3b and the shoulder bolts can also be of other tolerance grades.

[0029] Figures 7 and 8A show a drive unit for travel, in which the wheels 5b1 of a travel transport robot are assembled to a reduction gear 2 to which mounting plates 3a and 3b are attached. The drive shaft 5a1 is inserted into the hollow output shaft 2b of the reduction gear 2, and the collar 5c2 on the opposite output side is fitted onto the male threaded portion 5a3 on the opposite output side of the drive shaft, and the fixing nut 5d2 on the opposite output side is fastened. Furthermore, the drive shaft 5a1 is inserted into the hole 5b2 of the drive wheel 5b1, and the output side flat washer 5c1 is fitted onto the male threaded portion 5a2 on the output side of the drive shaft, and the fixing nut 5d1 on the output side is fastened.

[0030] By adopting this structure, as shown in Figure 8B, the clearance dimension 6a between the mounting surfaces 3c and 3d and the upper surface 2g of the gearbox case can be reduced, and the height dimension 6b from the running surface of the wheel 5b1 to the mounting surfaces 3c and 3d can be reduced.

[0031] The mounting surfaces 3c and 3d may be positioned slightly above the top surface 2g of the gearbox case. For example, as described above, when the height dimension H2 (Figure 2A) of the gearbox output side region 2c of the gearbox 2 is 90 mm, the height dimension H3 of the mounting plates 3a and 3b may be set to 91 mm, and the mounting surfaces 3c and 3d may be positioned 1 mm above the top surface 2g of the case. In this case, even if there is a slight slope on the top surface 2g of the case due to manufacturing using the die-casting method, contact between the top surface 2g of the case and the object to be mounted can be avoided, and deformation of the gearbox case due to such contact can be prevented. As a result, the clearance dimension 6a becomes 1 mm, and the mounting plate does not protrude significantly from the height dimension of the gearbox of 90 mm (reference numeral H2), and the height dimension can be reduced compared to the mounting structure shown in Figure 1. When the gearbox mounting structure of this embodiment is used in a mobile transport robot, the low profile of the mobile transport robot can be ensured.

[0032] <Other Embodiments> Since the non-output side mounting plate 3b is a separate part from the reducer 2, tapped holes 7a, which would be impossible or difficult to machine directly into the case 2k of the reducer 2 as shown in Figure 9A, can be machined into the non-output side end face of the non-output side mounting plate 3b. Using these tapped holes 7a, additional functional components 7b can be attached to the non-output side of the reducer 2 as shown in Figure 9B. Examples of additional functional components include encoders for position detection, safety encoders, and electromagnetic brakes.

[0033] Figure 10A is a perspective view of the gearbox 2, with mounting plates 3a and 3b attached, as shown in Figure 3, viewed from a different angle. The mounting surfaces 3c and 3d face in the positive z-axis direction. The four through holes 3a1-a, 3a1-b, 3a1-c, and 3a1-d of the mounting plate 3a are equally spaced along the rotational direction of the output shaft 2b and equidistant from the axis of the output shaft 2b. Similarly, the four through holes 3b1-a, 3b1-b, 3b1-c, and 3b1-d of the mounting plate 3b (Figure 5A) are equally spaced along the rotational direction of the output shaft 2b and equidistant from the axis of the output shaft 2b.

[0034] If mounting plates 3a and 3b shown in Figure 10A are removed, rotated 90 degrees counterclockwise with respect to the positive x-axis, and then reattached, the result will be as shown in Figure 10B. That is, mounting surfaces 3c and 3d are facing the positive y-axis. Surfaces 3c4 and 3d4 facing the positive z-axis may be flush with the top surface 2g of the gearbox case.

[0035] If the mounting plates 3a and 3b shown in Figure 10B are removed, rotated 90 degrees counterclockwise with respect to the positive x-axis, and then reattached, the result will be as shown in Figure 10C. That is, the mounting surfaces 3c and 3d are facing the negative z-axis direction. The surfaces 3c3 and 3d3 facing the positive z-axis direction may be flush with the top surface 2g of the gearbox case. Furthermore, the assembly shown in Figure 10C can also be inverted so that the mounting surfaces 3c and 3d face upwards, and then attached to the object to be mounted.

[0036] As shown in Figures 10A to 10C, the mounting surfaces 3c and 3d on the object to be mounted can be set in three different ways. In all three directions, it is possible to minimize the clearance dimension 6a between the mounting surface and the side of the gearbox case.

[0037] Furthermore, on the output-side mounting plate 3a, clearance dimensions 6a, tapped holes 3e, and positioning pin holes 3f can also be provided on each of the two surfaces parallel to the output shaft 2b other than the mounting surface 3c (the surface 3c2 located on the positive y-axis side of the two surfaces facing each other in the y-axis direction on the mounting plate 3c in Figure 10A, and the surface 3c3 facing the mounting surface 3c in the z-axis direction). This allows any of the three surfaces 3c, 3c2, and 3c3 to be selectively used as the mounting surface without changing the positional relationship of the output-side mounting plate 3a with respect to the reduction gear 2. The same applies to the non-output-side mounting plate 3b.

[0038] As shown in Figures 11A1 and 11A2, the output-side mounting plate 3a of the drive unit 9 has a mounting surface 3c facing the positive z-axis direction and a mounting surface 3c' facing the negative z-axis direction, while the non-output-side mounting plate 3b has a mounting surface 3d facing the positive z-axis direction and a mounting surface 3d' facing the negative z-axis direction. Mounting surfaces 3c and 3d are on a certain horizontal plane, and mounting surfaces 3c' and 3d' are on a different horizontal plane. Mounting surfaces 3c and 3c' are provided with a clearance dimension 6a, tapped holes 3e, and positioning pin holes 3f, while mounting surfaces 3d and 3d' are provided with a clearance dimension 6a and tapped holes 3e. By preparing two such drive units 9 and combining one drive unit 9 with a drive unit 9' which is the other drive unit 9 inverted vertically, as shown in Figure 11B, the four mounting surfaces 3c, 3d, 3c', and 3d' are arranged on the same horizontal plane. In this way, a pair of drive units equipped with two wheels 5b1 positioned spaced apart in the vehicle width direction can be constructed.

[0039] <Effects> According to the above embodiment, the gearbox is clamped between two mounting plates facing each other in the output axial direction. Therefore, the height dimension of the mounting structure can be reduced compared to a mounting structure using an L-shaped mounting plate. Furthermore, while keeping the height dimension of the gearbox mounting structure to about the same as the height dimension of the gearbox alone, tapped holes for mounting to the object to be mounted can be provided on both mounting plates. When used in a mobile transport robot, the low profile of the mobile transport robot can be ensured. In addition, because the gearbox is clamped in the output axial direction, the overall rigidity of the mounting structure is increased compared to when an L-shaped mounting plate is used.

[0040] Since the output mounting plate is coupled with a spigot projection provided on the output side region (flange surface) of the speed reducer, it is easy to position the output mounting plate parallel to the output side region of the speed reducer, and alignment of the output mounting plate with respect to the axis of the speed reducer output shaft is also easy. Further adjustments are not required when mounting the speed reducer to the mounting object. The spigot projection, which is commonly provided on speed reducers, can be used as is for the spigot coupling with the output mounting plate. There is no need to significantly change the dimensions of the speed reducer with a commonly used flange surface mounting structure, and the mounting plate can be added later.

[0041] Shoulder bolts are passed through the non-output side mounting plate, the reducer, and the output side mounting plate, and the shoulders of the shoulder bolts fit into the through holes in the output side mounting plate and the non-output side mounting plate. Therefore, it is easy to position the non-output side mounting plate parallel to the output side area of ​​the reducer, and it is also easy to align the non-output side mounting plate with respect to the axis of the reducer output shaft. As a result, the mounting surfaces of both mounting plates are on the same plane, and the mounting accuracy to the object to be mounted is improved. In addition, since the shoulder bolts are passed through through holes in the four corners of the flange surface, which are commonly provided on reducers, the need for further processing of the reducer itself can be reduced.

[0042] Since there are three possible mounting surfaces for both mounting plates parallel to the output shaft of the gearbox, flexibility in mounting the gearbox can be ensured.

[0043] The following additional information is disclosed regarding the embodiments described above. <Note 1> The reduction gear is provided with two mounting plates that clamp the reduction gear in the direction of the output shaft of the reduction gear, On each of the two mounting plates, one surface parallel to the output shaft is a mounting surface for attaching the reduction gear to the object to be mounted. Gear reducer mounting structure. <Note 2> The gearbox mounting structure according to Appendix 1, wherein one of the two mounting plates has a spigot hole formed therein that fits with a spigot projection of the gearbox which is formed to protrude in the output axial direction of the gearbox. <Note 3> The gearbox mounting structure according to Appendix 1 or 2, wherein through holes parallel to the output shaft are formed in the two mounting plates and the case of the gearbox, a female thread is formed on a part of the inner circumferential surface of the through hole in one of the mounting plates, a shoulder bolt is passed through the through holes in the two mounting plates and the through hole in the case, and the male thread of the shoulder bolt is fastened to the female thread. <Note 4> A gearbox mounting structure according to any one of the appendices 1 to 3, wherein one of a plurality of surfaces parallel to the output shaft on each of the two mounting plates is selected as the mounting surface.

[0044] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications and changes are possible based on the technical concept of the present invention. [Explanation of Symbols]

[0045] 1 electric motor 2 Reducer 2b Reducer output shaft 2c Reducer output side area 2d Reducer non-output shaft side area 2e Inlay protrusion 2f Through hole part 3a Output side mounting plate 3a1-a,b,c,d Through hole part 3a2 Fitting section 3a3 Female thread section 3a4 Inlay hole 3b Mounting plate on the opposite side of the output 3b1-a,b,c,d Through hole part 3b2 Inner surface 3c, 3d mounting surface 3e tapped hole 3f Positioning pin hole 4a Shoulder bolt 4b Shoulder 4c Male thread section

Claims

1. The reduction gear is provided with two mounting plates that clamp the reduction gear in the direction of the output shaft of the reduction gear, On each of the two mounting plates, one surface parallel to the output shaft is a mounting surface for attaching the reduction gear to the object to be mounted. Gear reducer mounting structure.

2. The gearbox mounting structure according to claim 1, wherein one of the two mounting plates has a spigot hole formed therein that engages with a spigot projection of the gearbox which is formed to protrude in the output axial direction of the gearbox.

3. The gearbox mounting structure according to claim 1 or 2, wherein through holes parallel to the output shaft are formed in the two mounting plates and the case of the gearbox, a female thread is formed on a part of the inner circumferential surface of the through hole in one of the mounting plates, a shoulder bolt is passed through the through holes in the two mounting plates and the through hole in the case, and the male thread of the shoulder bolt is fastened to the female thread.

4. The gearbox mounting structure according to claim 1 or 2, wherein one of a plurality of surfaces parallel to the output shaft on each of the two mounting plates is selected as the mounting surface.

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