Rotating table

Abstract

The rotary table (1) of the present invention has a base body (10), a worm wheel (21), an inner ring (22), a plurality of rolling elements, and a worm unit (30). The worm unit (30) includes: a worm (31) which is held so as to be rotatable about an axis and has a second gear (31A) meshing with a first gear (215); and a worm housing (32) which surrounds the worm (31) and holds the worm (31) and is fixed in a manner such that a planar contact surface contacts a holding surface. A cylindrical pin (33) protruding from one surface is arranged on one of the holding surface and the contact surface. A first recess (11) for accommodating the pin (33) is formed on the other of the holding surface and the contact surface. The first recess (11) has a width corresponding to the pin (33) and extends in the radial direction of the worm wheel (21).

Description

Technical Field

[0001] This application claims priority based on Japanese Application No. 2020-005902, filed on January 17, 2020, and incorporates all the contents of the aforementioned Japanese Application into this application. Background Art

[0002] There is known a rotary table including a worm wheel having a first gear formed over the entire circumference thereof and a worm having a second gear meshing with the first gear (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-177841. Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the above-mentioned turntable, the clearance (backlash) between the first gear of the worm wheel and the second gear of the worm is adjusted to ensure smooth rotation of the worm wheel and worm. It is preferable to easily adjust the backlash between the first and second gears. Therefore, one object of the present invention is to provide a turntable that allows easy adjustment of the backlash between the gears of the worm wheel and worm.

[0008] Means used to solve problems

[0009] The turntable according to the present invention comprises: a base body having a planar retaining surface; a worm wheel rotatably arranged on the base body and having an outer peripheral surface with a first gear formed thereon over the entire circumference; an inner ring arranged on the inner peripheral side of the worm wheel and fixed to the base body; a plurality of rolling elements rollably arranged on the inner peripheral surface of the worm wheel and the outer peripheral surface of the inner ring; and a worm unit fixed to the retaining surface. The worm unit includes: a worm held rotatably about the axis and having a second gear meshing with the first gear; and a worm housing surrounding and retaining the worm, and being fixed so as to contact the retaining surface at a planar contact surface. A cylindrical pin protruding from one surface is arranged on one of the retaining surface and the contact surface. A first recess for accommodating the pin is formed on the other of the retaining surface and the contact surface. The first recess has a width corresponding to the pin and extends in the radial direction of the worm wheel.

[0010] Effects of the Invention

[0011] According to the above-described rotating table, the backlash between the gears of the worm wheel and the worm can be easily adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic perspective view showing the structure of the turntable in the first embodiment.

[0013] Figure 2 This is a schematic plan view showing the structure of the turntable in the first embodiment.

[0014] Figure 3 This is a schematic plan view showing the structure of the turntable in the first embodiment.

[0015] Figure 4 It is a schematic plan view showing the structure of the base body.

[0016] Figure 5 This is a schematic cross-sectional view showing the structure of the turntable in the first embodiment.

[0017] Figure 6 This is a schematic cross-sectional view showing the structure of the turntable in the first embodiment.

[0018] Figure 7 This is a schematic cross-sectional view showing the structure of the turntable in the first embodiment.

[0019] Figure 8 This is a schematic cross-sectional view showing the structure of the turntable in the first embodiment.

[0020] Figure 9 It is a schematic side view showing the structure of the worm unit.

[0021] Figure 10 It is a schematic perspective view showing the structure of a worm housing.

[0022] Figure 11 This is a schematic cross-sectional view showing the structure of the turntable in the first embodiment.

[0023] Figure 12 It is a schematic plan view showing the structure of the turntable in a state where the cover member and the worm housing are removed.

[0024] Figure 13 This is a schematic perspective view showing the structure of a turntable in the second embodiment.

[0025] Figure 14 It is a schematic perspective view showing the structure of the rotary table in a state where the worm unit is removed.

[0026] Figure 15 It is a schematic side view showing the structure of the rotary table in a state where the worm unit is removed.

[0027] Figure 16 It is a schematic cross-sectional view showing the structure of the turntable in a state where the worm unit is removed. DETAILED DESCRIPTION

[0028] [Overview of Embodiments]

[0029] First, an embodiment of the present invention will be described. The turntable of the present invention comprises: a base body having a planar retaining surface; a worm wheel rotatably arranged on the base body and having an outer circumferential surface with a first gear formed thereon over the entire circumference; an inner ring arranged on the inner circumference of the worm wheel and fixed to the base body; a plurality of rolling elements rollably arranged on the inner circumferential surface of the worm wheel and the outer circumferential surface of the inner ring; and a worm unit fixed to the retaining surface. The worm unit includes: a worm rotatably held about the axis and having a second gear meshing with the first gear; and a worm housing surrounding and retaining the worm, secured to the retaining surface with a planar contact surface. A cylindrical pin protruding from one of the retaining surface and the contact surface is disposed on one of the retaining surface and the contact surface. A first recess for accommodating the pin is formed on the other of the retaining surface and the contact surface. The first recess has a width corresponding to the pin and extends in the radial direction of the worm wheel.

[0030] In the turntable of the present invention, a cylindrical pin is disposed on one of the retaining surface and the contact surface, and a first recess is formed on the other of the retaining surface and the contact surface. The first recess has a width corresponding to the pin and extends radially along the worm wheel. Before the worm housing is secured to the base body, inserting the pin into the first recess allows the worm housing to move radially while restricting its movement tangentially to the worm wheel. Furthermore, the worm housing can be rotated relative to the base body, with the pin serving as a fulcrum. In this state, the pin is inserted into the first recess, and the worm unit is brought radially toward the first gear, bringing the first and second gears into contact with an appropriate force. Thus, the backlash between the first and second gears can be appropriately adjusted by the radial movement of the worm housing and its rotation around the pin. Therefore, the backlash between the first and second gears can be easily adjusted. Thus, the turntable of the present invention makes it easy to adjust the backlash between the worm wheel and worm gears.

[0031] In the aforementioned turntable, a threaded hole may be formed in at least one of the base body and the worm housing, the threaded hole communicating with the first recess and having an opening facing the outer peripheral surface of the pin. The turntable may also include a first screw that is threaded into the threaded hole and has a tip portion that contacts the outer peripheral surface of the pin. After adjusting the relative position of the worm housing with respect to the base body, the first screw is screwed into the threaded hole so that the tip portion contacts the outer peripheral surface of the pin. This restricts relative movement of the worm housing with respect to the base body. Consequently, changes in the backlash between the first and second gears over time can be suppressed.

[0032] In the aforementioned turntable, the worm housing may include a facing surface that faces the outer peripheral surface of the worm wheel. The facing surface may also include a first through-hole that exposes the second gear. The worm housing may also include a flange portion protruding from the facing surface, the flange portion covering the side surface of the first gear that faces the facing surface, on the side opposite to the base body in the axial direction of the worm wheel. This structure can reduce the ingress of foreign matter into the contact area between the first gear and the second gear, and can also reduce the dispersion of grease outside the turntable.

[0033] In the above-mentioned rotating table, a grease supply hole can also be formed on the worm housing, and the grease supply hole passes through the outer wall other than the facing surface to the facing surface. The grease supply hole can also have a first opening portion on the facing surface. The first opening portion can also be formed separately from the first through hole in the circumferential direction of the worm wheel. By forming the grease supply hole, it is possible to supply grease to the first gear and the second gear in a state where the worm housing is fixed to the base body. In addition, by supplying grease from the upper side of the rotation of the area where the first gear and the second gear are in contact while the worm wheel and the worm are rotating, it is easy to supply grease to the area where the first gear and the second gear are in contact.

[0034] The above-mentioned turntable may also include a cover member that surrounds the first gear and is fixed to the base body. By including such a cover member, it is possible to reduce the situation where grease splashes to the outside of the turntable.

[0035] In the above-mentioned rotating table, the rolling elements may include first and second rollers. The first and second rollers may be arranged alternately in the circumferential direction. The central axis of the first roller may intersect the central axis of the second roller. By including the first and second rollers as described above, a rolling bearing suitable for supporting loads applied in multiple directions by the worm wheel and inner ring can be formed.

[0036] [Specific example of embodiment]

[0037] Next, an example of a specific embodiment of the turntable of the present invention will be described with reference to the accompanying drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals and their repeated descriptions are omitted.

[0038] (Implementation Method 1)

[0039] Figure 1 1 is a schematic perspective view showing the structure of the turntable in Embodiment 1. Figure 1 In FIG, the Z-axis direction is a direction extending along the rotation axis R of the worm wheel (axial direction). Figure 2 It is a schematic plan view showing the structure of a turntable. Figure 3 It is from Figure 2 A plan view of the turntable from the opposite side. Figure 5Is to turn the table along Figure 2 A cross-sectional view of the state cut along line AA in FIG. Figure 6 It will Figure 5 The area α in the cross-sectional view is shown in an enlarged magnification. Figure 7 Is to turn the table along Figure 2 A cross-sectional view of the state where the BB is cut. Figure 8 Is to turn the table along Figure 2 A cross-sectional view of the CC cut state. Figure 11 This is a cross-sectional view showing an enlarged view of the area around the first gear and the second gear in contact with each other. Figure 12 Yes and remove Figure 2 A plan view of the state of the cover component and the worm housing of the rotary table.

[0040] Reference Figures 1 to 3 The rotating table in the first embodiment includes a base body 10 , a rolling bearing unit 20 , a worm unit 30 , and screws 51 , 52 , and 53 .

[0041] Reference Figure 1 , the base body 10 has a flat plate shape. Figure 4 The base body 10 has a first surface 101, a second surface 102 as a holding surface, and a third surface 103. When viewed from above in the Z-axis direction, the first surface 101 and the second surface 102 are aligned in the Y-axis direction. Figure 1 The thickness of the area corresponding to the first surface 101 is thicker than the thickness of the area corresponding to the second surface 102. That is, the height of the second surface 102 in the Z-axis direction is lower than the height of the first surface 101. The first surface 101 and the second surface 102 are connected by the third surface 103. Figure 4 , the first surface 101 has a planar shape. When viewed from above in the Z-axis direction, the first surface 101 has a rectangular shape. Four through holes 105 are formed at the corners of the first surface 101 and pass through in the thickness direction. A through hole 107 is formed on the first surface 101 and passes through in the thickness direction. When viewed from above in the Z-axis direction, the through hole 107 has a circular shape. When viewed from above in the Z-axis direction, a circular annular recess 101B is formed on the first surface 101 so as to surround the through hole 107. In addition, a ring-shaped recess 101A is formed so as to surround the recess 101B. Refer to Figure 7 The thickness of the region of the first surface 101 corresponding to the recess 101A is thicker than the thickness of the region of the first surface 101 corresponding to the recess 101B. Figure 4 The recesses 101A and 101B have the same shape as the worm wheel 21 and the inner ring 22 described later (see Figure 1) corresponding to the shape. Multiple (eight in this embodiment) threaded holes 106 are formed at equal intervals in the circumferential direction in the recess 101B. Multiple (four in this embodiment) threaded holes 104 are formed at intervals in the circumferential direction on the outer circumference of the recess 101A on the first surface 101.

[0042] Reference Figure 4 , when viewed from above in the Z-axis direction, the second surface 102 has a rectangular shape. The length L3 of the second surface 102 in the X-axis direction is shorter than the length L4 of the first surface 101 in the X-axis direction. The second surface 102 has a planar shape. Four through holes 108A, 108B, 108C, and 108D are formed on the second surface 102 and pass through in the thickness direction. The inner diameters of the through holes 108A, 108B, 108C, and 108D are larger than the inner diameters of the screws 53 described later (see Figure 3 ) has a larger outer diameter than the threaded portion on the second surface 102. In the second surface 102, a first recess 11 is formed between the through hole 108C and the through hole 108D. When viewed from above in the Z-axis direction, the first recess 11 is formed in a region of the long side that is closer to the side opposite to the first surface 101 than the center of the second surface 102 in the Y-axis direction. In the X-axis direction, when viewed from the through hole 108C, a through hole 109 that penetrates in the thickness direction is formed on the side opposite to the first recess 11. Figure 4 and Figure 6 A first threaded hole 12 communicating with the first recess 11 is formed on the base body 10. The first threaded hole 12 extends along the Y-axis direction.

[0043] Reference Figure 7 and Figure 8 The rolling bearing unit 20 includes a worm wheel 21 as an outer ring, an inner ring 22, a plurality of first rollers 23 and a plurality of second rollers 24 as rolling elements, and a cover member 25. The worm wheel 21 is disposed on the first surface 101 of the base body 10. The worm wheel 21 is positioned so as to correspond to the position of the first surface 101 where the recess 101A is formed. The worm wheel 21 is positioned so that the direction along the rotation axis R of the worm wheel 21 is aligned with the direction perpendicular to the first surface 101 (the Z-axis direction). The worm wheel 21 has an annular shape.

[0044] The worm wheel 21 includes an inner circumferential surface 21A, an outer circumferential surface 21B, an axial end face 21D, and an axial end face 21E on the opposite side of the end face 21D. A first gear 215 is formed on the entire circumference of the outer circumferential surface 21B. The inner circumferential surface 21A includes a first region 211 and a second region 212. The first region 211 is arranged at a position closer to the end face 21D side than the center of the inner circumferential surface 21A in the axial direction. The second region 212 is arranged at a position closer to the end face 21E side than the center of the inner circumferential surface 21A in the axial direction. In the Z-axis direction, a circularly recessed space 21C is formed between the first region 211 and the second region 212. The space 21C is surrounded by a circular first rolling surface 213 and a circular second rolling surface 214. The first rolling surface 213 and the second rolling surface 214 intersect (are orthogonal). The space 21C is formed along the rolling path of the plurality of first rollers 23 and the plurality of second rollers 24. Refer to Figure 1 and Figure 2 In the worm wheel 21 , a plurality of (eight in this embodiment) threaded holes 216 are formed at equal intervals in the circumferential direction.

[0045] Reference Figure 7 and Figure 8 The inner ring 22 has an annular shape. It is positioned on the inner circumference of the worm wheel 21. It is positioned so as to correspond to the location on the first surface 101 where the recess 101B is formed. The inner ring 22 includes an outer circumferential surface 22A, an inner circumferential surface 22B, an axial end surface 22D, and an end surface 22E axially opposite the end surface 22D. The outer circumferential surface 22A includes a third region 221 and a fourth region 222. The third region 221 is positioned axially closer to the end surface 22D than the center of the outer circumferential surface 22A. The fourth region 222 is positioned axially closer to the end surface 22E than the center of the outer circumferential surface 22A. In the Z-axis direction, an annular recessed space 22C is formed between the third and fourth regions 221, 222. Space 22C is surrounded by an annular third rolling surface 223 and an annular fourth rolling surface 224. The third rolling surface 223 and the fourth rolling surface 224 intersect (are orthogonal to each other). Space 22C is formed along the rolling paths of the plurality of first rollers 23 and the plurality of second rollers 24. The first rolling surface 213 and the fourth rolling surface 224 face each other. In this embodiment, in a cross section including the rotation axis R, the first rolling surface 213 and the fourth rolling surface 224 are arranged parallel to each other. The second rolling surface 214 and the fourth rolling surface 224 face each other. In this embodiment, in a cross section including the rotation axis R, the second rolling surface 214 and the fourth rolling surface 224 are arranged parallel to each other.

[0046] Reference Figure 1 , a plurality of (8 in this embodiment) threaded holes 225 are formed on the inner ring 22 at equal intervals in the circumferential direction. Figure 2 and Figure 4 , the position where the threaded hole 225 is formed is aligned with the position where the threaded hole 106 is formed on the base body 10, and the screw 52 (refer to Figure 3 ) is screwed into the threaded holes 106, 225. In this way, the inner ring 22 is fixed on the base body 10.

[0047] Reference Figure 7 and Figure 8 The first roller 23 and the second roller 24 have a cylindrical shape. The first roller 23 and the second roller 24 are arranged alternately in the circumferential direction. The first roller 23 is arranged so as to be in contact with the second rolling surface 214 and the third rolling surface 223 on the outer peripheral surface 23A and to be able to roll. The second roller 24 is arranged so as to be in contact with the first rolling surface 213 and the fourth rolling surface 224 on the outer peripheral surface 24A and to be able to roll. The center axis P1 of the first roller 23 intersects (orthogonally) with the center axis P2 of the second roller 24. The state in which the center axis P1 of the first roller 23 intersects (orthogonally) with the center axis P2 of the second roller 24 means that when the center of gravity of the first roller 23 and the second roller 24 pass through a predetermined point when the worm wheel 21 rotates, the center axis P1 of the first roller 23 intersects (orthogonally) with the center axis P2 of the second roller 24. In this way, the worm wheel 21 can rotate around the rotation axis R relative to the base body 10.

[0048] Reference Figure 7 The cover member 25 is arranged on the first surface 101. The cover member 25 is arranged on the outer peripheral side of the worm wheel 21. The cover member 25 has an annular shape. The cover member 25 surrounds the first gear 215. In this embodiment, the first gear 215 is exposed from a part of the area of the cover member 25. Figure 2 The cover member 25 is formed with a plurality of (four in this embodiment) screw holes 251 spaced apart in the circumferential direction. Figure 2 and Figure 4 The position where the threaded hole 251 is formed is aligned with the position where the threaded hole 104 is formed on the base body 10 , and the screw 51 is screwed into the threaded holes 104 and 251 . In this way, the cover member 25 is fixed to the base body 10 .

[0049] Reference Figure 1 , the worm unit 30 is arranged on the second surface 102. Figure 9 and Figure 12The worm unit 30 includes a worm 31, a worm housing 32, a pin 33, a motor 34, a coupling 35, a cover 36, a first support bearing 37, and a second support bearing 38. The worm 31 has a cylindrical shape. A second gear 31A is formed on the outer peripheral surface of the worm 31. The second gear 31A meshes with the first gear 215. A cover 36 is disposed on one end side of the worm 31. The worm wheel 31 is rotatably supported relative to the cover 36 via the first support bearing 37. A coupling 35 is disposed on the other end side of the worm 31. The motor 34 is fixed to the motor housing 35A by screws. As the motor 34 in this embodiment, for example, a synchronous motor or an AC servo motor can be used. The worm 31 is rotatably supported relative to the coupling 35 via the second support bearing 38. The worm 31 is connected to the motor 34 via the coupling 35. The motor 34 is electrically connected to an external power supply (not shown). The motor 34 has a ring 34A for manual rotation.

[0050] Reference Figure 10 The worm housing 32 has a rectangular parallelepiped shape with an internal space S. The worm housing 32 includes a first outer wall 32A, a second outer wall 32B serving as a contact surface, a third outer wall 32C, a fourth outer wall 32D, a fifth outer wall 32E, and a sixth outer wall 32F. The first outer wall 32A, the second outer wall 32B, the third outer wall 32C, the fourth outer wall 32D, and the sixth outer wall 32F are planar. The first outer wall 32A and the second outer wall 32B are arranged side by side in the Z-axis direction. The first outer wall 32A and the second outer wall 32B are arranged parallel to each other. The third outer wall 32C and the fourth outer wall 32D are arranged side by side in the X-axis direction. The third outer wall 32C and the fourth outer wall 32D are arranged parallel to each other. The fifth outer wall 32E and the sixth outer wall 32F are arranged side by side in the Y-axis direction.

[0051] Reference Figure 6 A recess 321 is formed on the second outer wall surface 32B. Figure 10 , an opening portion 324A communicating with the internal space S is formed on the third outer wall surface 32C. Four threaded holes 327 are formed around the opening portion 324A. An opening portion 324B communicating with the internal space S is formed on the fourth outer wall surface 32D. The fifth outer wall surface 32E has a facing surface 322 that is curved (arc-shaped) and recessed in the Y-axis direction. A first through hole 323 communicating with the internal space S is formed on the facing surface 322. The worm housing 32 includes a flange portion 325 protruding from the facing surface 322 in the Y-axis direction. The front end portion 325A in the protruding direction of the flange portion 325 has a curved (arc-shaped) shape. The front end portion 325A constitutes a portion of the fifth outer wall surface 32E.

[0052] A grease supply hole 326 is formed in the worm housing, extending from the third outer wall surface 32C to the facing surface 322. The grease supply hole 326 has a first opening 326A on the facing surface 322 and a second opening 326B on the third outer wall surface 32C. The first opening 326A is formed spaced apart from the first through hole 323 in the X-axis direction. A grease nipple 328 (see FIG. 3 ) is installed to close the second opening 326B. Figure 11 ). By installing the grease nipple 328, the grease supply amount can be easily adjusted.

[0053] Reference Figure 6 A cylindrical pin 33 is arranged so as to protrude from the second outer wall surface 32B. The pin 33 is embedded in the recess 321 on the second outer wall surface 32B. In this embodiment, the pin 33 has a width L5 (see FIG. 1 ) greater than the width L5 of the first recess 11 in the X-axis direction. Figure 4 ) slightly smaller outer diameter.

[0054] Reference Figure 9 and Figure 10 The position where the threaded hole 327 is formed in the worm housing 32 is aligned with the position where the threaded hole (not shown) is formed in the cover 36, and the screw 54 is screwed in. In this way, the worm housing 32 is fixed to the cover 36. Figure 9 and Figure 11 The worm housing 32 surrounds the worm 31. The worm 31 is accommodated in the inner space S formed by the worm housing 32. The second gear 31A of the worm 31 is exposed from the first through hole 323 on the worm housing. Figure 6 The second outer wall surface 32B of the worm housing 32 contacts the second surface 102 of the base body 10. The facing surface 322 of the worm housing 32 faces the outer peripheral surface 21B of the worm wheel 21. The second gear 31A exposed from the first through hole 323 of the facing surface 322 meshes with the first gear 215 of the worm wheel 21.

[0055] Reference Figure 6 The flange portion 325 covers the side surface 215A of the first gear 215 facing the facing surface 322 on the side opposite to the base body 10 in the Z-axis direction. In this embodiment, the distance L1 between the side surface 325A of the flange portion 325 and the outer peripheral surface 21B of the worm wheel 21 facing the side surface 325A is less than 1 mm. The distance L1 is preferably greater than 0.5 mm and less than 1 mm. The distance L2 between the wall surface 325B of the flange portion 325 facing the side surface 215A of the first gear 215 and the side surface 215A of the first gear 215 is less than 1 mm. The distance L2 is preferably greater than 0.5 mm and less than 1 mm. By setting the distances L1 and L2 within the above range, the scattering of grease to the outside of the turntable 1 can be reduced. In addition, the labyrinth structure can reduce the entry of foreign matter from the outside.

[0056] Reference Figure 6 The pin 33 is inserted into the first recess 11 of the long hole of the base body 10. The turntable 1 further includes a hexagon socket set screw 40 as a first screw screwed into the first threaded hole 12 of the base body 10. The front end 40A of the hexagon socket set screw 40 contacts the outer peripheral surface 33A of the pin 33. Figure 3 and Figure 4 The positions of the through holes 108A, 108B, 108C, and 108D formed on the base body 10 are aligned with the positions of the threaded holes (not shown) formed on the worm housing 32, and the screws 53 are screwed in. In this way, the worm housing 32 is fixed to the base body 10.

[0057] Next, the method of fixing the worm unit 30 to the base body 10 in this embodiment will be described. First, a structure in which the rolling bearing unit 20 is mounted on the base body 10 is prepared. Figure 2 As shown, the worm unit 30 is arranged on the base body 10. At this time, referring to Figure 6 , the pin 33 pressed into the recess 321 formed in the worm housing 32 is inserted into the first recess 11 on the base body 10. Then, referring to Figure 2 、 Figure 3 as well as Figure 4 By inserting the screws 53 into the through holes 108A, 108B, 108C, and 108D, the worm housing 32 is temporarily fixed to the base body 10. Figure 2 The worm unit approaches the first gear 215 along the radial direction of the worm, so that the first gear 215 and the second gear 31A are in contact with each other with appropriate force. Figure 6 , screw the hexagon socket set screw 40 into the first threaded hole 12. Then, refer to Figure 2 and Figure 3 By further tightening the screw 53 , the worm housing 32 is fixed to the base body 10 .

[0058] In the turntable 1 of this embodiment, the first recess 11 has a width corresponding to the pin 33 (slightly larger than the outer diameter of the pin 33) and is shaped to extend radially of the worm wheel 21. Inserting the pin 33 into the first recess 11 allows the worm housing 32 to move radially while restricting its movement in the tangential direction of the worm wheel 21. Furthermore, the worm housing 32 can be rotated relative to the base body 10 with the pin 33 serving as a fulcrum. By moving the worm unit 30 closer to the first gear 215 in the worm's radial direction and bringing the first gear 215 into contact with the second gear 31A with an appropriate force, the backlash between the first gear 215 and the second gear 31A can be appropriately adjusted through the radial movement of the worm housing 32 and its rotation with the pin 33 serving as a fulcrum. This facilitates adjustment of the backlash between the first gear 215 and the second gear 31A. Thus, according to the turntable 1 of this embodiment, the backlash between the first gear 215 and the second gear 31A can be easily adjusted.

[0059] In the above embodiment, a first threaded hole 12 is formed, communicating with the first recess 11 and having an opening facing the outer peripheral surface of the pin 33. The rotary table 1 includes a hexagon socket set screw 40 that is screwed into the first threaded hole 12 and has a tip 40A that contacts the outer peripheral surface 33A of the pin 33. After adjusting the relative position of the worm housing 32 with respect to the base body 10, the hexagon socket set screw 40 is screwed into the first threaded hole 12. This restricts the relative movement of the worm housing 32 with respect to the base body 10. Consequently, the backlash between the first gear 215 and the second gear 31A can be suppressed from changing over time.

[0060] In the above embodiment, the worm housing 32 has a facing surface 322 that faces the outer peripheral surface 21B of the worm wheel 21. The worm housing 32 includes a flange portion 325 that protrudes from the facing surface 322 and covers the side surface 215A of the first gear 215 that faces the facing surface 322. This structure can reduce the intrusion of foreign matter into the contact area between the first gear 215 and the second gear 31A, and can also reduce the scattering of grease outside the turntable 1.

[0061] In the above embodiment, a grease supply hole 326 is formed in the worm housing 32. The grease supply hole 326 has a first opening portion 326A on the facing surface 322. The first opening portion 326A is formed separately from the first through hole 323 in the circumferential direction of the worm wheel 21. By forming the grease supply hole 326, grease can be supplied while the worm housing 32 is fixed to the base body 10. In addition, by supplying grease from the upper side of the rotation in the area where the first gear 215 and the second gear 31A contact while the worm wheel 21 and the worm 31 are rotating, grease can be easily supplied to the area where the first gear 215 and the second gear 31A contact.

[0062] In the above embodiment, reference is made to Figure 9 and Figure 11 When viewed from the area where the first gear 215 contacts the second gear 31A, the first opening 326A of the grease supply hole 326 is formed on the first outer wall surface 32A side in the Z-axis direction. Figure 9 and Figure 11 The first opening 326A is formed slightly closer to the first outer wall 32A than the center of the facing surface 322 in the Z-axis direction. When viewed from the first through-hole 323, the first opening 326A is formed on the third outer wall 32C side in the X-axis direction. This structure allows grease to be supplied to the contact area between the first gear 215 and the second gear 31A while utilizing gravity to move the grease. This facilitates grease supply to the contact area between the first gear 215 and the second gear 31A.

[0063] In the above embodiment, the turntable 1 includes the cover member 25. By including the cover member 25, it is possible to reduce the grease from scattering to the outside of the turntable 1.

[0064] In the above embodiment, referring to Figure 5 、 Figure 7 as well as Figure 8 The trajectory of the midpoint S1 on the center axis P1 of the first roller 23 and the trajectory of the midpoint S2 on the center axis P2 of the second roller 24 are contained in an imaginary plane U. In this embodiment, imaginary plane U includes the area where the first gear 215 and the second gear 31A are in contact. In the Z-axis direction, the position of the rotation center of the first gear 215 coincides with the position of the rotation center of the second gear 31A. This configuration of the rolling bearing unit 20 and the worm unit 30 facilitates optimal tooth contact between the first gear 215 and the second gear 31A, enabling efficient force transmission from the second gear 31A to the first gear 215.

[0065] In the above embodiment, the pin 33 is arranged on the second outer wall surface 32B of the worm housing 32 and the first recess 11 is formed on the base body 10. However, this is not limited to this. The pin 33 may also be arranged on the second surface 102 of the base body 10 and the first recess 11 may be formed on the second outer wall surface 32B of the worm housing.

[0066] In the above embodiment, the first threaded hole 12 for screwing the hexagon socket set screw 40 is formed in the base body 10. However, the present invention is not limited to this. The first threaded hole 12 may be formed in the worm housing 32 when the pin 33 is arranged so as to protrude from the second surface 102 of the base body 10 and the first recess 11 is formed in the second outer wall surface 32B of the worm housing 32. Alternatively, the first threaded hole 12 may be formed in both the base body 10 and the worm housing 32.

[0067] In the above-mentioned embodiment, a threaded hole extending in the direction of the plane containing the rotation axis R of the worm wheel 21 (in the Y-axis direction) may be formed on the pin 33. A threaded hole extending in the Y-axis direction may be formed on the base body 10 in a manner corresponding to the position where such a threaded hole is formed. The position where the threaded hole is formed on the pin 33 may be aligned with the position where the threaded hole is formed on the base body 10, and the hexagon socket bolt may be screwed in. The hexagon socket bolt may also be screwed in in a manner such that the head of the hexagon socket bolt contacts the side surface of the base body 10. By screwing in the hexagon socket bolt, the pin 33 can be moved in the direction of the arrow Y. By adopting such a structure, it is easy to adjust the tooth gap between the first gear 215 and the second gear 31A with high precision.

[0068] In the above embodiment, the worm wheel 21 is configured as the outer ring of the rolling bearing unit 20. However, the present invention is not limited thereto, and the rolling bearing unit 20 may include an outer ring that is separate from the worm wheel 21. By configuring the worm wheel 21 as an integral outer ring of the rolling bearing unit 20, the rolling bearing unit 20 can be made more compact and the rigidity of the housing can be increased.

[0069] In the above embodiment, first rollers 23 and second rollers 24 are used as rolling elements. The first rollers 23 and second rollers 24 may be arranged alternately in the circumferential direction. The central axis P1 of the first roller 23 intersects the central axis P2 of the second roller 24. The use of the first rollers 23 and second rollers 24 creates a rolling bearing suitable for supporting loads applied in multiple directions by the worm wheel 21 and inner ring 22. Using such a crossed rolling bearing allows for a compact, small-section design of the turntable 1. Furthermore, the first rollers 23 and second rollers 24 are inserted after removing the cover (not shown) from the inner ring 22. While the above embodiment describes the use of the first rollers 23 and second rollers 24 as rolling elements, this is not limiting; balls may also be used. While the above embodiment describes the worm housing 32 including the flange 325, this is not limiting; the worm housing 32 does not necessarily need to include the flange 325. In the above embodiment, the grease supply hole 326 is formed in the worm housing 32. However, the present invention is not limited thereto and the grease supply hole 326 may not be formed in the worm housing 32. In addition, either the worm housing 32 includes the flange portion 325 or the grease supply hole 326 is formed in the worm housing 32.

[0070] (Implementation Method 2)

[0071] Next, a second embodiment of the turntable 1 of the present invention will be described. The turntable 1 in the second embodiment has essentially the same structure as the turntable 1 in the first embodiment, and achieves the same effects. However, the second embodiment differs from the first embodiment in that the base body 10 comprises a block that is movable in the Y-axis direction. The following description focuses on the differences from the first embodiment.

[0072] Figure 13 This is a schematic perspective view showing the structure of a turntable in the second embodiment. Figure 14 It is a perspective view showing the structure of the turntable in a state where the worm unit 30 is removed. Figure 15 It is a side view showing the structure of the turntable in a state where the worm unit 30 is removed. Figure 16 It is a cross-sectional view showing the structure of the turntable in a state where the worm unit 30 is removed. Figure 16 Is to turn the table along Figure 15 A cross-sectional view of the state in which DD is cut.

[0073] Reference Figure 13 and Figure 14 The turntable 1 in the second embodiment further includes a block 41 and a hexagon socket head bolt 42. Figure 14 and Figure 16, a first recess 11 is formed on the second surface 102 of the base body 10. In this embodiment, when viewed from above in the Z-axis direction, the first recess 11 has the shape of a rounded rectangle. The first recess 11 is defined by side walls 11A, 11B, 11C, 11D and a bottom wall 11E. The side walls 11A and 11B face each other. The side walls 11C and 11D face each other. The side walls 11A and 11B are parallel to a plane (YZ plane) containing the rotation axis R of the worm wheel 21. A first threaded hole 12 and a second threaded hole 13 extending in the Y-axis direction are formed on the side surface of the base body 10. The first threaded hole 12 and the second threaded hole 13 are formed at intervals in the X-axis direction. The first threaded hole 12 and the second threaded hole 13 are formed so as to be connected to the first recess 11.

[0074] Reference Figure 16 , the block 41 is inserted into the first recess 11 of the base body 10. In the present embodiment, the block 41 has a rectangular parallelepiped shape. In the present embodiment, the block 41 has a rounded rectangular shape when viewed from above in the Z-axis direction. The block 41 has outer wall surfaces 412A, 412B, 412C, and 412D. The outer wall surface 412A and the outer wall surface 412B are arranged parallel to the Y-axis direction. The outer wall surface 412C and the outer wall surface 412D face each other. The outer wall surface 412C and the outer wall surface 412D are arranged spaced apart in the Y-axis direction. A cylindrical second recess 41A is formed on the block 41 and passes through in the Z-axis direction. The second recess 41A has a shape corresponding to the pin 33. A third threaded hole 41B extending in the Y-axis direction is formed on the outer wall surface 412C of the block 41 facing the side wall surface 11C. The block 41 has a width corresponding to the first recess 11. The length between the outer wall surface 412A and the outer wall surface 412B in the X-axis direction corresponds to the length between the side wall surface 11A and the side wall surface 11B in the X-axis direction. In this embodiment, the length between the outer wall surface 412A and the outer wall surface 412B in the X-axis direction is slightly smaller than the length between the side wall surface 11A and the side wall surface 11B in the X-axis direction. The length of the block 41 in the radial direction of the worm wheel 21 is shorter than the radial length of the first recess 11. In this embodiment, the length between the outer wall surface 412C and the outer wall surface 412D in the Y-axis direction is shorter than the length between the side wall surface 11C and the side wall surface 11D in the Y-axis direction. In other words, a small gap is formed between the outer wall surface 412C and the side wall surface 11C, and between the outer wall surface 412D and the side wall surface 11D, allowing the block 41 to move. Therefore, the block 41 can move in the Y-axis direction.

[0075] Reference Figure 16The hexagon socket set screw 40 is screwed into the first threaded hole 12, with the tip 40A of the hexagon socket set screw 40 contacting the outer peripheral surface 412 of the block 41. The second threaded hole 13 formed in the base body 10 is aligned with the third threaded hole 41B formed in the block 41, and the hexagon socket bolt 42 is screwed in. The head 42A of the hexagon socket bolt 42 contacts the side surface of the base body 10.

[0076] Next, a method for fixing the worm unit 30 in this embodiment to the base body 10 will be described. Figure 14 As shown in FIG. 1 , a structure in which a rolling bearing unit 20 is mounted on a base body 10 is prepared. Figure 13 As shown, the worm unit 30 is arranged on the base body 10. At this time, the pin 33 protruding from the worm housing 32 is pressed into the second recess 41A on the block 41. Then, referring to Figure 3 、 Figure 13 as well as Figure 14 , by inserting the screws 53 into the through holes 108A, 108B, 108C, and 108D, the worm housing 32 is temporarily fixed to the base body 10. Then, referring to Figure 13 and Figure 16 , tighten the hexagon socket set screw 40 and the hexagon socket bolt 42. By tightening the hexagon socket set screw 42, the block 41 can move in the direction of arrow Y. By tightening the hexagon socket set screw 40, the block 41 can move in the direction opposite to arrow Y. Specifically, by tightening the hexagon socket set screw 40, the pin 33 is pressed in the direction opposite to arrow Y, and by tightening the hexagon socket bolt 42, the pin 33 is pulled out in the direction of arrow Y. After appropriately adjusting the screwing amount of the hexagon socket set screw 40 and the hexagon socket bolt 42, the worm unit 30 is secured to the base body 10 by further tightening the screw 53.

[0077] The turntable 1 of the present invention comprises a base body 10 having a planar retaining surface (second surface 102); a worm wheel 21 rotatably disposed on the base body 10 and having an outer circumferential surface with a first gear 215 formed thereon along its entire circumference; an inner ring 22 disposed on the inner circumference of the worm wheel 21 and fixed to the base body 10; a plurality of rolling elements (first rollers 23 and second rollers 24) rollably disposed on the inner circumferential surface of the worm wheel 21 and the outer circumferential surface of the inner ring 22; and a worm unit 30 fixed to the retaining surface. The worm unit 30 includes a worm 31 rotatably retained about the axis and having a second gear 31A meshing with the first gear 215; and a worm housing 32 surrounding and retaining the worm 31, secured to the retaining surface by contact with the planar contact surface (second outer wall surface 32B). A cylindrical pin 33 protruding from one of the retaining surface and the contact surface is disposed. A first recess 11 is formed on the other of the retaining surface and the contact surface. This first recess 11 has a pair of sidewall surfaces 11A and 11B parallel to a plane (YZ plane) containing the rotation axis R of the worm wheel 21. A block 41 is inserted into the first recess 11. This block 41 has a width corresponding to that of the first recess 11 and is shorter in the radial direction of the worm wheel 21 than the first recess 11. A cylindrical second recess 41A is formed in the block 41 to accommodate the pin 33.

[0078] According to the turntable 1 of the second embodiment, the backlash between the first gear 215 and the second gear 31A can be easily adjusted as in the first embodiment. By adopting the structure of the turntable 1 of the second embodiment, the backlash between the first gear 215 and the second gear 31A can be easily adjusted with high precision.

[0079] The embodiments disclosed herein are illustrative in all respects and should not be construed as limiting in any respect. The scope of the present invention is defined not by the foregoing description but by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0080] Description of Reference Numerals

[0081] 1 Rotating table; 10 Base body; 11 First recess; 11A, 11B, 11C, 11D side wall surfaces; 11E Bottom wall surface; 12 First threaded hole; 13 Second threaded hole; 20 Unit; 21 Worm gear; 21A, 22B inner circumference; 21B, 22A, 23A, 24A, 33A, 412 outer circumference; 21C, 22C space; 21D, 21E, 22D, 22E end surfaces; 22 Inner ring; 23 First roller; 24 Second roller; 25 Cover member; 30 Worm unit; 31 worm; 31A second gear; 32 worm housing; 32A first outer wall; 32B second outer wall; 32C third outer wall; 32D fourth outer wall; 32E fifth outer wall; 32F sixth outer wall; 33 pin; 34 motor; 34A ring; 35 coupling; 35A motor housing; 36 cover; 37 first support bearing; 38 second support bearing; 40 hexagon socket set screw; 40A, 325A front end; 41 block; 41A second recess portion; 41B third threaded hole; 42 hexagon socket head bolt; 42A head; 51, 52, 53, 54 screws; 101 first surface; 101A, 101B, 321 recessed portion; 102 second surface; 103 third surface; 104, 106, 216, 225, 251, 327 threaded holes; 105, 107, 108A, 108B, 108C, 108D, 109 through-holes; 211 first area; 212 second area; 213 first rolling surface; 214 second rolling surface; 215 first gear; 215A, 325A side surface; 221 third area; 222 fourth area; 223 third rolling surface; 224 fourth rolling surface; 322 facing surface; 323 first through hole; 324A, 324B openings; 325 flange; 325B wall surface; 326 grease supply hole; 326A first opening; 326B second opening; 328 grease nipple; 412A, 412B, 412C, 412D outer wall surfaces.

Claims

1. A rotating table, wherein: have: A base body having a planar retaining surface; a worm wheel, arranged on the base body so as to be rotatable about an axis and having an outer peripheral surface on which a first gear is formed over the entire circumference; an inner ring, disposed on the inner circumference of the worm wheel and fixed to the base body; a plurality of rolling elements rollably disposed on the inner circumferential surface of the worm wheel and the outer circumferential surface of the inner ring; as well as a worm unit, fixed to the retaining surface, The worm unit comprises: a worm gear held rotatably about an axis and having a second gear meshing with the first gear; and A worm housing surrounds the worm and holds the worm, and is fixed in such a manner that a flat contact surface contacts the holding surface. A cylindrical pin protruding from one of the holding surface and the contact surface is arranged on the one surface. A first recessed portion for accommodating the pin is formed on the other of the retaining surface and the contact surface, and the first recessed portion extends in the radial direction of the worm wheel. The pin is movable in the first recess in the radial direction of the worm wheel. A first threaded hole is formed in at least one of the base body and the worm housing, the first threaded hole being connected to the first recess and having an opening facing the outer peripheral surface of the pin. The rotation table further has a first screw that is screwed into the first threaded hole and has a front end portion that contacts the outer peripheral surface of the pin.

2. The turntable according to claim 1, wherein The worm housing has a facing surface facing the outer peripheral surface of the worm wheel, A first through hole is formed on the facing surface to expose the second gear. The worm housing includes a flange portion protruding from the facing surface, and the flange portion covers a side surface of the first gear facing the facing surface, which is on the opposite side from the base body in the axial direction of the worm wheel.

3. The turntable according to claim 2, wherein: A grease supply hole is formed on the worm housing, and the grease supply hole penetrates from the outer wall other than the facing surface to the facing surface. The grease supply hole has a first opening on the facing surface. The first opening is formed to be separated from the first through hole in the circumferential direction of the worm wheel.

4. The turntable according to any one of claims 1 to 3, wherein: The rotating table further includes a cover member that surrounds the first gear and is fixed to the base body.

5. The turntable according to any one of claims 1 to 3, wherein: The rolling element includes a first roller and a second roller, The first rollers and the second rollers are alternately arranged in the circumferential direction of the worm wheel. A central axis of the first roller intersects a central axis of the second roller.

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