JP4558534B2 - transmission - Google Patents

Description

  The present invention relates to a transmission, and more particularly to a ball-type transmission.

  Various types of transmissions of this type have been proposed, and some examples will be described below.

  As a first example, there is a cup-type gearless transmission disclosed in Patent Document 1. As shown in FIGS. 15 and 16, this transmission includes two shafts 110 and 120 that are rotatably supported on the same axis, and an inner cylinder (first shaft) fixed to the end of the shaft 110. And an outer cylinder (second rotating body) 125 fixed to the end of the shaft 120 and facing the outer periphery of the inner cylinder 115. Of the opposing surfaces of the inner cylinder 115 and the outer cylinder 125, an endless inclined groove (first groove) 115 a is provided on the opposing surface of the inner cylinder 115, and a plurality of sine wave grooves are provided on the opposing surface of the outer cylinder 125. A (second groove) 125a is provided. The transmission also has a guide cylinder 135 in which a plurality of narrow windows 135a different from the number of sine wave grooves 125a are formed in the equiangular axial direction and are rotatably inserted into the gap between the inner cylinder 115 and the outer cylinder 125. . In the guide tube 135, one sphere 130 is rotatably inserted into the narrow window 135a one by one, and the sphere 130 is engaged with the inclined groove 115a and the sine wave groove 125a on both exposed surfaces.

  As a second example, there is a transmission disclosed in Patent Document 2. Referring to FIGS. 17 and 18, the transmission includes a first roller 10 having a first repeating number of first grooves 12 </ b> A in the circumferential direction on the outer peripheral surface of a first shaft body having a circular cross section. And a second roller 20 having a second groove 22A having a second repetition number different from the first repetition number in the circumferential direction on the outer peripheral surface of the second shaft body having a circular cross section. The transmission also includes a third cylindrical roller 30 having a plurality of grooves 30 </ b> A extending in the axial direction at circumferential intervals on the inner diameter surface. In this transmission, the first roller 10 and the second roller 20 have a plurality of first balls 32 positioned in the first groove 21A and a plurality of first balls 32 positioned in the second groove 22A. The second roller 32 is opposed to the third roller 30 via the second ball 32. A plurality of grooves 30A of the third roller 30 are provided with retainers 31 that hold the first and second balls 32 and are slidable in the axial direction.

  As shown in the exploded view of FIG. 18, the first outer roller 10 includes a first cylindrical body 11 closer to the input side and a second cylindrical body 12 closer to the output side having a smaller diameter. A first groove 12A having a first repetition number Ks is formed in the outer diameter portion of the second cylindrical body 12 so as to extend in the circumferential direction. The second outer roller 20 includes a first cylindrical body 21 closer to the output side and a second cylindrical body 22 closer to the input side having a smaller diameter. A second groove 22A having substantially the same width as the first groove 12A and a second number of repetitions Ks · Ki is formed in the outer diameter portion of the second cylindrical body 22 so as to extend in the circumferential direction. . Note that the number of repetitions is a groove having a periodic function waveform such as a sine wave whose amplitude periodically changes in the first and second grooves 12A and 22A in this example, and the amplitude in one round, that is, 360 degrees. It means how many times the maximum value of is repeated.

  The inner roller 30 is also a cylindrical body, and has an inner diameter in which the second cylindrical bodies 12 and 22 can be fitted. A plurality of grooves 30A extending in the axial direction at equal intervals in the circumferential direction are formed in the inner diameter portion. ing. The maximum number of grooves 30A is Ks (Ki-1) or Ks (Ki + 1). Each groove 30A is provided with a retainer 31 so as to be slidable along the groove 30A. The retainers 31 are slidable only along the grooves 30A and are not restricted to each other. Each retainer 31 holds two rolling elements, here balls 32, at intervals in the axial direction. Of the two balls 32 held by the retainer 31, one is on the first groove 12 </ b> A of the second cylindrical body 12, and the other is on the second groove 22 </ b> A of the second cylindrical body 22. It is configured to be able to roll. The retainer 31 has not only a function of holding the ball 32 but also a function of receiving a tension / compression force acting via the two balls 32.

  Such a structure is housed in a casing, and the first and second outer rollers 10 and 20 and the inner roller 30 are restrained from moving in the axial direction using a bearing or the like. Of course, the first and second outer rollers 10, 20 and the inner roller 30 are concentrically combined.

  The number of the grooves 30A of the inner roller 30, that is, the number of the retainers 31, can be any number as long as the distance of r × 360 ° / {Ks (Ki ± 1)} (r is a positive integer) can be maintained. Hereinafter, the case where the sign of ± in the above formula is − is referred to as arrangement A, and the case where + is + is referred to as arrangement B.

  As a first example, a development view in the circumferential direction when the number of repetitions of the first groove 12A is 1 and the number of repetitions of the second groove 22A is 16 (that is, Ks = 1, Ki = 16 and a reduction ratio of 1/16). Is shown in FIG. That is, FIG. 19A shows an example of the case where the groove 30A of the inner roller 30 has an interval of r × 360 ° / {Ks (Ki−1)} (arrangement A), and r × 360 ° / {Ks ( An example of the case of (Ki + 1)} (arrangement B) is shown in FIG.

  As a third example, there is a transmission disclosed in Patent Document 3. Referring to FIGS. 20 to 22, this transmission includes a driving member (first rotating body) 310 and a driven member (second rotating body) that are conjugate pairs of devices that are rotatable about a common axis. 320). The driving member 310 is connected to the input shaft 315, and the driven member 320 is connected to the output shaft 325. The transmission also includes conversion means for converting the angular velocity of the input shaft 315 to the angular velocity of the output shaft 325. The conversion means includes a retainer 330, and the retainer 330 includes at least one radial slot 330a for swinging a ball 335 formed by connecting the driving member 310 and the driven member 320 therein.

  The driving member 310 and the driven member 320 are opposed to each other with the retainer 330 interposed therebetween. As shown in FIG. 22, an annular groove 310 a is formed on the opposing surface of the driving member 310, and the driven member 320 is opposed to the driving member 310. A substantially triangular wave-shaped groove 320a is formed in the circumferential direction so as to face the groove 310a and a part of the slot 330a. The retainer 330 is positioned between the driving member 310 and the driven member 320 around the common axis, whereby the ball 335 connects the driving member 310 and the driven member 320. With such a configuration, the angular velocity of the input shaft 315 is converted into the angular velocity of the output shaft 325.

  However, in any of the first to third examples, there is an element that oscillates once or twice for one rotation of the input shaft, so that the natural vibration due to the input rotation speed appears at a low frequency. There is a problem.

  A fourth example has been proposed as an example of solving the problem of low-frequency natural vibration caused by the input rotational speed (see Patent Document 4).

  In the fourth example, the rotation of the first member of the robot, the second member of the robot rotatably supported by the first member, and the electric motor integrally attached to the first member is reduced. There has been proposed an industrial robot joint device including a speed reducer that transmits the second member. Specifically, the speed reduction device includes a front-stage rotation conduction means for decelerating the rotation of the electric motor and a rear-stage rotation conduction means for reducing the output rotation of the front-stage rotation conduction means. Further, the electric motor has a rotation speed corresponding to a natural frequency of a drive system configured to include the electric motor, the speed reduction device, and the second member in a normal control range, and the latter-stage rotation conduction means includes: A camshaft to which the output of the preceding stage rotation conduction means is input; an external gear driven by rotation of the camshaft; and an internal gear meshing with the external gear, and a fixed number of times per rotation of the camshaft. It is constituted by a planetary gear device that has a characteristic of causing substantial torque fluctuations and substantially exciting the drive system. Further, the preceding stage rotation conduction means is constituted by a gear device having a predetermined reduction ratio which is different from the planetary gear device, and the reduction gear ratio of the gear device is equal to the reduction ratio per second in the normal control range of the electric motor. Is set to be equal to or lower than the natural frequency of the drive system.

  However, in this fourth example, in order to move the low-frequency natural vibration to a higher frequency, it is necessary to use a two-stage type in which different types of planetary gear devices are separately incorporated. However, there is a problem that the size of the entire apparatus becomes large.

JP 60-179563 A International Publication No. WO2004 / 38256 Japanese translation of PCT publication No. 6-508664 Japanese Patent Publication No. 8-22516

  Accordingly, an object of the present invention is to provide a transmission capable of moving natural vibration to a high frequency without changing the structure or size.

  According to the present invention, the first rotating body having the first endless groove defined by the first repetition number Ks on the surface of the first shaft body, and the first shaft on the surface of the second shaft body. A second rotating body having a second endless groove defined by a second number of repetitions Ks · Ki different from the number of repetitions Ks, and at least one groove or slot for holding a ball, A ball holding portion for coupling the first rotating body and the second rotating body via a ball, wherein the first repetition number Ks is m / n (where n is a positive number of 2 or more) , M is a positive integer greater than or equal to 1 and expressed as n> m), Ki is a value adjusted so that Ks · Ki is an integer, and defines a reduction ratio 1 / Ki or a speed increase ratio In addition, there is provided a transmission characterized in that the number of grooves or slots is represented by Ks (Ki ± 1) at the maximum.

  According to such a configuration, since the first repetition number of the first endless groove can be 1/2 or 1/3, the reciprocation can be 1 reciprocation in 2 rotations or 1 reciprocation in 3 rotations. Transition to a higher frequency is possible.

  In the transmission according to the first aspect of the present invention, the first rotating body has the first endless groove formed in the circumferential direction on the outer peripheral surface of the first shaft body having a circular cross section. The second rotating body is formed by forming the second endless groove in the circumferential direction on the outer peripheral surface of the second shaft body having a circular cross section, and the ball holding portion has an inner diameter. A cylindrical body having a plurality of grooves extending in the axial direction at intervals in the circumferential direction on the surface, each of which is provided with a retainer that holds the first and second balls and is slidable in the axial direction. The first rotating body and the second rotating body are the first ball positioned in the first endless groove and the second endless groove positioned in the second endless groove. It is characterized by facing each of the ball holding portions via a second ball.

  According to such a configuration, the natural vibration can be shifted to a high frequency, and in addition, it is not necessary to form a groove having a meandering shape on the inner diameter surface of the cylindrical body, which facilitates manufacture.

  In the transmission according to the second aspect of the present invention, the first rotating body has the first endless groove formed in the circumferential direction on the outer peripheral surface of the first shaft body having a circular cross section. The second rotating body is formed by forming the second endless groove in the circumferential direction on the inner peripheral surface of a cylindrical body having a circular cross section having a larger diameter than the outer peripheral surface of the first shaft body. And the ball holding portion is a cylindrical body having a plurality of grooves extending in the axial direction at intervals in the circumferential direction, and an outer peripheral surface of the first shaft body and an inner peripheral surface of the second shaft body The ball is held in each groove, and a part of the ball exposed to the outside from the ball holding portion is in the first endless groove and exposed to the inside from the ball holding portion. When a part of the ball is in the second endless groove, the first rotating body and the second rotating body are And wherein the bonded via.

  In any of the transmissions according to the first and second aspects, the first and second endless grooves are each a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove Is apparently composed of two grooves when the first number of repetitions Ks = 1/2, and these two grooves intersect with each other at an angular position of amplitude 0 and are in a symmetrical relationship with each other. May be.

  Alternatively, in any of the transmissions according to the first and second aspects, the first and second endless grooves are grooves having a periodic function waveform in which the amplitude changes periodically, and the first The endless groove is apparently composed of three grooves when the first number of repetitions Ks = 1/3, and two of these three grooves are 180 ° from the angular position of each maximum amplitude. One of the two grooves and one of the two grooves intersect each other at a second angular position that is 180 ° apart from the first angular position. In addition, they may be symmetrical with each other.

  In the transmission according to the third aspect of the present invention, the first rotating body is formed by forming the first endless groove in the circumferential direction on the tip surface of the first shaft body, The second rotating body is formed by forming the second endless groove in the circumferential direction on the tip surface of the second shaft body facing the tip surface of the first shaft body, and holding the ball The portion is a disc having a plurality of grooves extending in the radial direction at intervals in the circumferential direction, and is disposed between the tip surface of the first shaft body and the tip surface of the second shaft body. A ball is held in each groove, and a part of the ball exposed to the first shaft body side from the ball holding portion is in the first endless groove, and the second holding groove from the ball holding portion. Since a part of the ball exposed to the shaft body side is in the second endless groove, the first rotating body and the second rotating body are And wherein the bonded via Lumpur.

  According to such a configuration, the same effect as the transmission according to the first aspect can be obtained.

  In the transmission according to the third aspect, each of the first and second endless grooves is a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove is the first endless groove. When the number of repetitions of Ks = 1/2, it is apparently composed of two grooves, and these two grooves intersect each other at the angular position of amplitude 0, and each groove has a diameter of the disk passing through the angular position. The shape may be axisymmetric with respect to.

  Alternatively, in the transmission according to the third aspect, each of the first and second endless grooves is a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove is When the first number of repetitions Ks = 1/3, there are apparently three grooves, and two of the three grooves are first spaced 180 degrees from the angular position of the maximum amplitude. One of the two grooves and one of the two grooves intersect each other at a second angular position 180 degrees away from the first angular position, while intersecting each other at an angular position, The shape may be axisymmetric with respect to the diameter of the disk passing through the first and second angular positions.

  In conventional transmissions, the natural vibration cannot be moved to a high frequency unless a special element such as a planetary gear mechanism is incorporated into a two-stage type. Then, by setting the first number of repetitions Ks to 1/2 or 1/3, the number of repetitions of the high-speed side groove, that is, the first endless groove, can be made one reciprocation over two or three revolutions. The natural vibration can be moved to a higher frequency without significantly changing the machine structure or increasing the size.

  If the reduction ratio is 1 / i, a reduction ratio of i = 2 or higher can be obtained on the high speed side. Therefore, considering that the same reduction ratio as the high speed side groove repetition rate Ks = 1 is obtained, the low speed side groove repetition number is half. The following is sufficient, and compactness is possible.

  Further, in the conventional transmission, the radial moment of the shaft is generated due to the unbalance of the force due to the swing, but this is reduced.

  Embodiments of the present invention will be described below, but the present invention can be applied to any of the transmissions disclosed in Patent Documents 1, 2, and 3. Therefore, first, a first embodiment applied to the transmission disclosed in Patent Document 2 will be described. In this case, the following improvements are made to the transmission shown in FIGS. In the following description, it is assumed that the first outer roller 10 is on the input side (high speed side) and the second outer roller 20 is on the output side (low speed side). This is because the relationship between the input side and the output side may be reversed.

  In the transmission according to the first embodiment, the repetitive number Ks of the first groove (endless groove) 12A on the high speed side is set to m reciprocations with n rotations. That is, it is represented by Ks = m / n. Here, n is a positive integer of 2 or more, and m is a positive integer smaller than n, but 1 is preferable. When m is 1, Ks = 1 / n, and it is 1 reciprocation with 2 rotations, or 1 reciprocation with 3 rotations or more.

  On the other hand, the number of repetitions of the second groove (endless groove) 22A on the low speed side is Ks · Ki, but since Ks is less than 1, it may not be an integer, so Ki is set so that Ks · Ki becomes an integer. It needs to be adjusted. For example, when m is 1 and Ks = 1/2, Ki is a multiple of 2, and when Ks = 1/3, Ki is a multiple of 3.

  FIG. 1 shows a first example of the first embodiment, in which the first groove 12A, the second groove 22A, and the retainer when the reduction ratio is 1/16, Ks = 1/2, and Ki = 16. The relationship of 31 is shown with the development view of the circumferential direction. In particular, FIG. 1A shows the case of arrangement A, and FIG. 1B shows the case of arrangement B. In the case of the arrangement A, as described above, the retainers 31 that hold the two balls 32 are arranged at a 360 ° / {Ks (Ki-1)} interval with the maximum number (Ki-1). Are arranged at 360 ° / {Ks (Ki + 1)} intervals, with a maximum number of (Ki + 1).

  As shown in FIGS. 1A and 1B, the second groove 22A is formed with only one groove having a periodic function waveform such as a sine wave. On the other hand, the first groove 12A is composed of two grooves 12A-1 and 12A-2 having an apparent periodic function waveform. In particular, the two grooves 12A-1 and 12A-2 are halfway, that is, an angle with an amplitude of zero. It is realized by being formed so as to intersect at a position. The grooves 12A-1 and 12A-2 are symmetrical with respect to the line segment in the circumferential direction, the right end of the groove 12A-1 is connected to the left end of the groove 12A-2, and the right end of the groove 12A-2 The part is endless by connecting to the left end of the groove 12A-1. The two balls 32 are arranged so as to roll one by one in the first groove 12A and the second groove 22A, respectively. However, since the first groove 12A has two strips, when the ball 32 held in one retainer 31 is in one groove 12A-1, the ball 32 held in the adjacent retainer 31 is in the other groove 12A. -2 is arranged. That is, in this example, the balls 32 held by the adjacent retainers 31 are arranged so that one is in the groove 12A-1 and the other is in the groove 12A-2.

  The operation will be described in the case where the number of the retainers 31 is 1 and the circumferential position of the retainers 31 is restricted (that is, the inner roller 30 is fixed). The high-speed side roller, that is, the first outer roller 10 is rotated once. The first groove 12A causes the high-speed side ball, that is, the ball 32 in the first groove 12A to reciprocate in the axial direction Ks times. The movement is transmitted to the low speed side ball, that is, the ball 32 in the second groove 22A via the retainer 31, and the low speed side ball reciprocates the second groove 22A in the axial direction Ks times, so that the second outer roller 20 is decelerated by 1 / Ki rotation.

  Practically, a plurality of retainers 31 are installed, and the operation direction varies depending on the arrangement interval of the retainers 31. When the circumferential position of the retainer 31 is constrained (the inner roller 30 is fixed), the low speed side roller, that is, the second outer roller 20 is 360 ° / {Ks ( With a retainer interval of Ki-1)}, it rotates 1 / Ki, and with a retainer interval of 360 ° / {Ks (Ki + 1)}, it rotates -1 / Ki (minus means reverse rotation).

  When the second outer roller 20 is fixed, the retainer 31 is −1 / (Ki−1) at a retainer interval of 360 ° / {Ks (Ki−1)} with respect to one rotation of the first roller 10. Rotation is 1 / (Ki + 1) at a retainer interval of 360 ° / {Ks (Ki + 1)}.

  FIG. 2 shows a second example of the first embodiment, in which the first groove 12A, the second groove 22A, and the retainer when the reduction ratio is 1/18, Ks = 1/3, and Ki = 18. The relationship of 31 is shown with the development view of the circumferential direction. 2A shows the case of arrangement A, and FIG. 2B shows the case of arrangement B. In the case of the arrangement A, as described above, the retainers 31 that hold the two balls 32 are arranged at a 360 ° / {Ks (Ki-1)} interval with the maximum number (Ki-1). Are arranged at 360 ° / {Ks (Ki + 1)} intervals, with a maximum number of (Ki + 1).

  As shown in FIGS. 2A and 2B, the second groove 22A is formed with only one groove having a periodic function waveform such as a sine wave. On the other hand, the first groove 12A apparently comprises three grooves 12A-1, 12A-2, and 12A-3 having a periodic function waveform. In particular, among these three grooves 12A-1, 12A-2, 12A-3, the groove 12A-1 and the groove 12A-2 are located at a certain angular position, that is, 180 ° apart from the angular position of each maximum amplitude. The second angle that intersects at an angular position of 1 and the groove 12A-2 and the groove 12A-3 are 180 ° apart from the first angular position and 180 ° apart from the angular position of each maximum amplitude. It is formed to intersect at a position. The right end of the groove 12A-1 is connected to the left end of the groove 12A-2, and the right end of the groove 12A-2 is connected to the left end of the groove 12A-3. The right end of the groove 12A-3 is connected to the left end of the groove 12A-1, thereby forming a non-terminal groove. The two balls 32 are arranged so as to roll one by one in the first groove 12A and the second groove 22A, respectively. However, since the first groove 12A has three strips, when the ball 32 held by a retainer 31 is in the groove 12A-1, the ball 32 held by the retainer 31 adjacent to the right is in the groove 12A-2. Further, the ball 32 held by the retainer 31 adjacent to the right side is arranged so as to be in the groove 12A-3. That is, in this example, the balls 32 held by the retainer 31 are arranged in order in the grooves 12A-1, 12A-2, and 12A-3.

  The operation principle of this example will not be described because the reduction ratio is different only by the difference between the number of repetitions Ks and Ki described in the first example.

  Next, a second embodiment in which the present invention is applied to the transmission disclosed in Patent Document 1 will be described. In this case, the following improvements are made to the transmission shown in FIGS.

  FIG. 3 shows a first example of the second embodiment. Here, the inclined groove when the reduction ratio is 1/10, the number of repetitions of the first groove on the input side is Ks = 1/2, and Ki = 10 (the number of repetitions of the second groove on the output side is Ks · Ki = 5). The relationship between the (first endless groove) 115a, the sine wave groove (second endless groove) 125a, and the guide tube (ball holding portion) 135 (all shown in FIG. 16) is shown in a developed view in the circumferential direction. In this embodiment, one sphere 130 is held in each narrow window 135a of the guide tube 135.

  As described above, the narrow windows 135a that hold the sphere 130 are arranged at a maximum number of (Ki ± 1) at an interval of 360 ° / {Ks (Ki ± 1)}.

  As shown in FIGS. 3A to 3C, only one sine wave groove 125 a having a periodic function waveform is formed on the inner diameter surface of the outer cylinder 125. On the other hand, the inclined groove 115a formed on the outer diameter surface of the inner cylinder 115 apparently comprises two grooves 115a-1 and 115a-2 having a periodic function waveform, and these two grooves 115a-1 and 115a-2. Are formed so as to intersect at an angular position of zero amplitude. The grooves 115a-1 and 115a-2 are symmetrical with respect to the line segment in the circumferential direction, the right end of the groove 115a-1 is connected to the left end of the groove 115a-2, and the right end of the groove 115a-2 Is connected to the left end of the groove 115a-1, thereby forming an endless groove. The sphere 130 is arranged so that one side exposed from the guide tube 135 enters the inclined groove 115 and the other side exposed from the guide tube 135 enters the sine wave groove 125a. However, since the inclined groove 115a has two strips, when the sphere 130 held in one narrow window 135a is in one groove 115a-1, the sphere 130 held in the adjacent narrow window 135a is in the other groove 115a. -2 is arranged. That is, also in this example, the spheres 130 held by the adjacent narrow windows 135a are arranged so that one is in the groove 115a-1 and the other is in the groove 115a-2.

  3 (a) to 3 (c), the grooves 115a-1, 115a-2, the narrow window 135a, and the sine wave groove 125a are associated with the positions of the spheres 130 at the same angular positions. Show.

  FIG. 4 shows a second example of the second embodiment. The reduction ratio is 1/9, the number of repetitions of the first groove on the input side is Ks = 1/3, and Ki = 9 (the second value on the output side). The relationship between the inclined groove 115a, the sine wave groove 125a, and the guide cylinder 135 in the case of the number of groove repetitions Ks · Ki = 3) is shown in a developed view in the circumferential direction.

  As shown in FIGS. 4A to 4C, the sine wave groove 125a is formed with only one groove having a periodic function waveform. On the other hand, the inclined groove 115a apparently comprises three grooves 115a-1, 115a-2, and 115a-3 having a periodic function waveform. In particular, among these three grooves 115a-1, 115a-2, 115a-3, the groove 115a-1 and the groove 115a-2 are located at a certain angular position, that is, 180 ° apart from the angular position of each maximum amplitude. The second angle which intersects at the angular position of 1 and the groove 115a-2 and the groove 115a-3 are 180.degree. Apart from the first angular position and 180.degree. It is formed to intersect at a position. The right end of the groove 115a-1 is connected to the left end of the groove 115a-2, and the right end of the groove 115a-2 is connected to the left end of the groove 115a-3. The right end portion of the groove 115a-3 is connected to the left end portion of the groove 115a-1, thereby forming an endless groove. Since the inclined groove 115a has three strips, when the ball 130 held in a narrow window 135a is in the groove 115a-1, the ball 130 held in the narrow window 135a on the right is the grooves 115a-2 and 115a-. 3 and the sphere 130 held in the narrow window 135a adjacent to the right is arranged so as to be in the other of the grooves 115a-2 and 115a-3.

  The operation principle of the second embodiment will not be described because only the reduction ratio is different due to the difference between the number of repetitions Ks and Ki described in the first embodiment.

  Next, a third embodiment in which the present invention is applied to the transmission disclosed in Patent Document 3 will be described. In this case, the following improvements are made to the transmission shown in FIGS.

  FIG. 5 shows a first example of the third embodiment. Here, when the reduction ratio is 1/12, the number of repetitions of the first groove on the input side is Ks = 1/2, and Ki = 12 (the number of repetitions of the second groove on the output side is Ks · Ki = 6), The relationship between the groove (first endless groove) 310a, the substantially triangular wave-shaped groove (second endless groove) 320a, and the retainer 330 (see FIGS. 20 to 22) is the circular shape of the driven member 320. It is drawn on the front end surface, that is, the opposing surface that faces the circular front end surface of the drive member 310. Also in this embodiment, one ball 335 is held in the slot 330 a of the retainer 330.

  As described above, the slots 330a for holding the balls 335 are arranged at a maximum of (Ki ± 1) at an interval of 360 ° / {Ks (Ki ± 1)}.

  As shown in FIG. 5, only one groove 320 a having a periodic function waveform is formed in the circumferential direction on the opposing surface of the driven member 320. The groove 320a may be sinusoidal. On the other hand, the groove 310a formed on the opposing surface of the drive member 310 apparently consists of two grooves 310a-1 and 310a-2 having a periodic function waveform, and these two grooves 310a-1 and 310a-2 are respectively formed. Are formed so as to intersect at an angular position of 0 amplitude. The groove 310a-1 is centered on the center O of the driven member 320, and OR1 defined on the line segment with an angle of 0 ° shown in FIG. 5 is used as an initial radius in the + 180 ° direction and the −180 ° direction. It has a substantially annular shape drawn by gradually increasing it. On the other hand, the groove 310a-2 has an initial radius OR2 defined on a line segment having an angle of 180 ° larger than OR1, and is drawn by gradually increasing it toward the + 180 ° direction and the −180 ° direction. It has a substantially annular shape. And the groove | channel 310a-1 and the groove | channel 310a-2 become an endless groove | channel by making it cross | intersect at the angle position of 180 degrees. Each of the grooves 310 a-1 and 310 a-2 is line symmetric with respect to the diameter of the distal end surface of the driven member 320. Further, as in the first and second embodiments, the grooves 310a-1 and 310a-2 are necessarily overlapped with all the slots 330a somewhere. Since there are two grooves 310a, when the ball 335 held in one slot 330a is in one groove 310a-1, the ball 335 held in the adjacent slot 330a is in the other groove 310a-2. Placed in.

  FIG. 6 shows a second example of the third embodiment, in which the reduction ratio is 1/9, the number of repetitions of the first groove on the input side is Ks = 1/3, Ki = 9 (the second value on the output side The relationship between the annular groove 310a, the substantially triangular wave-shaped groove 320a, and the retainer 330 in the case of the groove repetition number Ks · Ki = 3) is depicted on the opposing surface of the driven member 320. Also in this embodiment, one ball 335 is held in the slot 330 a of the retainer 330.

  As shown in FIG. 6, only one groove 320 a having a substantially triangular waveform having a periodic function waveform is formed on the opposing surface of the driven member 320. On the other hand, the groove 310a apparently comprises three grooves 310a-1, 310a-2, and 310a-3 having a periodic function waveform. The groove 310a-1 is centered on the center O of the driven member 320, and OR1 defined on the line segment having an angle of 180 ° shown in FIG. 5 is used as the initial radius, and this is set in the + 180 ° direction and the −180 ° direction. It has a substantially annular shape drawn by gradually increasing it. On the other hand, the groove 310a-2 has an initial radius OR2 defined on a line segment having an angle of 0 ° larger than OR1, and is drawn by gradually increasing it toward the + 180 ° direction and the −180 ° direction. It has a substantially annular shape. Further, the groove 310a-3 is drawn by gradually increasing the initial radius OR3 defined on the line segment having an angle of 180 ° toward the + 180 ° direction and the −180 ° direction, which is larger than OR2. It has a substantially annular shape. The grooves 310a-1, 310a-2, 310a-3 are line symmetric with respect to the line segment R3-R1-O-R2. In particular, among these three grooves 310a-1, 310a-2, 310a-3, the groove 310a-1 and the groove 310a-2 intersect at a first angular position that is 180 ° apart from the angular position of the maximum amplitude. The grooves 310a-2 and 310a-3 are formed so as to intersect with each other at an angular position that is 180 ° apart from the first angular position and at an angular position that is 180 ° apart from the angular position of each maximum amplitude. It becomes an endless groove.

  Since the groove 310a has three strips, when the ball 335 held in a certain slot 330a is in the groove 310a-1, the ball 335 held in the right slot 330a is one of the grooves 310a-2 and 310a-3. Further, the ball 335 held in the slot 330a adjacent to the right is disposed so as to be in the other of the grooves 310a-2 and 310a-3.

  The operation principle of the third embodiment is also the same as that of the first embodiment because the reduction ratios Ks and Ki are different, so that the description is omitted.

  The transmission having the above configuration has the following effects.

  (1) Although it is known that the natural vibration generated in the transmission can be moved to a high frequency by providing the planetary gear mechanism, the reduction gear according to the present invention has a high-speed side groove (first endless groove). The natural vibration can be shifted to a high frequency without changing the structure and size by making the number of repetitions 1 reciprocation over 2 revolutions.

  (2) Since a reduction ratio of 2 or more can be obtained with the high-speed side groove, considering that the same reduction ratio as the high-speed side groove repetition rate Ks = 1 is obtained, the number of repetitions of the low-speed side groove (second endless groove) Can be reduced to less than half and can be made compact.

  (3) Further, in the conventional example, the radial moment of the shaft is generated due to the unbalance of the force due to the swing, but this is reduced.

  As mentioned above, although this invention was described about preferable embodiment, this invention is not restricted to said embodiment, The following changes are possible. Although the following description is applied to the first embodiment, the shape of the groove and the like can also be applied to the second and third embodiments.

  The first and second outer rollers 10 and 20 are each formed in a hollow cylindrical shape, but may be configured by a shaft body having a circular cross section that is not hollow.

  The first and second grooves 12A and 22A have a symmetric shape such as a sine wave shape as shown in FIG. 7 and a triangular wave shape as shown in FIG. 8, and asymmetric shape as shown in FIG. But it ’s okay. In the case of the triangular wave shape as shown in FIG. 9, the pressure angle can be made constant, and the load fluctuation on the ball can be made constant. On the other hand, the cross-sectional shapes of the first and second grooves 12A and 22A are simple arc shapes as shown in FIG. 10 (a), bearing arc shapes as shown in FIG. 10 (b), and shown in FIG. 10 (c). Any of such triangular shapes may be used, but particularly in the case of a bearing arc shape or a triangular shape, there is an advantage that a desired pressure angle with a ball can be easily obtained and load resistance is improved.

  In addition, it is preferable that the retainer 31 is made of a material that is easy to slide or is coated with a material that facilitates sliding.

  Hereinafter, with reference to FIG. 11, another example of the retainer having the function of holding the ball 32 and the function of receiving the tension / compression force will be described. FIG. 11A shows a first example in which a rolling unit 51 is interposed as a sliding member between the inner roller 30 and the retainer 31-1. Here, although the rolling unit 51 is interposed on each of the three side surfaces of the retainer 31 facing the inner wall of the groove 30A having a quadrangular section in the inner roller 30, it is disposed on at least the side surface facing the bottom wall of the groove 30A. Just do it.

  FIG. 11B shows a second example in which a rolling unit 52 is interposed as a sliding member between the inner roller 30 and the retainer 31-2. Here, the rolling unit 52 is parallel to the sliding direction. It arrange | positions in the position corresponding to the two corner parts of the retainer 31-2. For this reason, each of the inner wall of the inner roller 30 and the two corner portions of the retainer 31-2 is formed with curved concave portions 30a and 31-2a for accommodating the rolling unit 52 so as to extend in the axial direction. .

  In either of the first and second examples, the rolling unit can be, for example, a pin roller or a unit in which a plurality of balls are held by a retainer.

  In both the first and second examples, the receiving portions 31-11 and 31-21 formed on the retainers 31-1 and 31-2 for accommodating the balls 32 are as shown in FIG. In addition, in terms of the cross-sectional shape, it is not an arc shape having the same radius, but has a shape in which arcs having different centers as shown in FIG. Of course, the shapes of the receiving portions 31-11 and 31-21 are the same in any cross section as long as the cross section is a plane passing through the center line of the receiving portion. According to such a receiving portion, the contact radius can be freely selected according to the size of the ball 32.

  In addition, the receiving portions 31-11 and 31-21 are formed by using a cutting tool. In consideration of the clearance of the tip of the cutting tool, the receiving portions 31-11 and 31-21 are formed at the innermost portion of the receiving portions 31-11 and 31-21. Furthermore, it is preferable to form the recesses 31-12 and 31-22. The concave portions 31-12 and 31-22 can be used as reservoir portions when the lubricant is injected into the receiving portions 31-11 and 31-21.

  The above description regarding the receiving portion of the ball 32 is exactly the same for the retainer 31 described with reference to FIG.

  FIG. 11C and FIG. 11D show third and fourth examples in which the above-described sliding member is also used as the ball 32.

  In FIG. 11C, the retainer 31-3 has a width smaller than the diameter of the ball 32, and a receiving portion 31-31 for holding the ball 32 is formed. The cross-sectional shape of the receiving portion 31-31 may be either an arc shape or a spherical shape having the same radius. On the other hand, the groove 30A formed in the inner roller 30 has a quadrangular section 30A-1 for accommodating the retainer 31-3 and a curved section 30A-2 for receiving a part of the ball 32. Of course, the groove 30A composed of the rectangular section 30A-1 and the curved section 30A-2 is formed to extend in the axial direction. Also in this example, the rolling unit 53 is disposed as a sliding member between the bottom of the groove 30A and the retainer 31-3.

  In addition, it cannot be overemphasized that the rolling units 51-53 in the said 1st-3rd example may be implement | achieved by another known sliding member. For example, the sliding member may be realized by coating at least one of the facing portions of the retainer and the inner roller 30 with a friction reducing material by plating, for example.

  In FIG.11 (d), the retainer 31-4 has a width smaller than the diameter of the ball | bowl 32, and it is formed so that the receiving part 31-41 for hold | maintaining the ball | bowl 32 may penetrate the retainer 31-4 main body. ing. That is, the ball 32 is formed so that a part of the upper part and a part of the lower part of the ball 32 are exposed. As shown in FIG. 13, the cross-sectional shape of the receiving portion 31-41 is not a simple through hole, but is formed so that the diameter gradually decreases as it approaches the upper end surface near the upper portion, that is, the inner roller 30 side. By making the receiving portion 31-41 into such a cross-sectional shape, the ball 32 held by the retainer 31-4 can have a function of holding the retainer 31-4. That is, when the receiving portion 31-4 is a simple through hole, the retainer 31-4 to be held in the groove 30A of the inner roller 30 falls to the outer roller side. However, the retainer 31-4 can be prevented from falling by making the receiving portion 31-4 into the above-described shape.

  On the other hand, the groove 30A formed in the inner roller 30 has a rectangular section 30A-3 for receiving the retainer 31-4 and a curved section 30A-4 for receiving a part of the ball 32. Of course, the groove 30A composed of such a rectangular section 30A-3 and a curved section 30A-4 is formed to extend in the axial direction. If necessary, a concave portion similar to the concave portions 31-12 and 31-22 described in the first and second examples may be provided in the curved surface portion 30A-4 as a lubricant receiving portion in the axial direction. The groove 30A may be realized only by the curved surface portion 30A-4 that does not have the quadrangular section 30A-3. That is, only the ball 32 may be received by the groove 30A having only the curved surface portion.

  In the third and fourth examples, since the ball 32 rolls in the groove 30A, it can be said that the ball 32 also serves as a sliding member. However, in the fourth example, the retainer 31-4 and the inner roller 30 Between them, a rolling unit may be arranged.

  In the third and fourth examples, the ball 32 receives a tangential force (a tangential force in contact with the inner diameter of the inner roller 30 shown in the figure). , 31-4 can be reduced.

  Of the above four examples, the third and fourth examples are superior in that they have the advantage of reducing the load acting on the retainers 31-3 and 31-4 as described above. The example 4 is the most effective because the structure is simpler than the first to third examples and the cross-sectional area with respect to the tension / compression force can be approximately doubled.

  FIG. 14 shows an actual machine structure in which a speed reducer having the same structure as that shown in FIG. 18 is housed in a casing. Here, in order to make the first outer roller 10 easy, the first cylinder 11 closer to the input side and the second cylinder 12 ′ closer to the output side having a larger diameter than the first cylinder 11 are bolts 61. It is fixed by. A first groove 12A is formed in the outer diameter portion of the second cylindrical body 12 'so as to extend in the circumferential direction. An input shaft 100 is fastened to the first cylindrical body 11 with a bolt (not shown). In order to facilitate the manufacture of the second outer roller 20, a circular plate 21 ′ having an output shaft 200 integrally and a second cylindrical body 22 ′ closer to the input side having a larger diameter are connected by bolts 62. It is fixed. A second groove 22A is formed in the outer diameter portion of the second cylindrical body 22 'so as to extend in the circumferential direction. An input side casing 110 composed of a bearing support ring 111 and a cover plate 112 is fastened to the input side of the inner roller 30, and an output side casing 210 composed of a bearing support ring 211 and a mounting plate 212 is assembled to the output side. ing. The bearing support ring 111 is fastened to the inner roller 30 with a bolt 63, and the cover plate 112 is fastened to the bearing support ring 111 with a bolt 64. On the other hand, the bearing support ring 211 is fastened to the inner roller 30 with a bolt 65, and the mounting plate 212 is fastened to the bearing support ring 211 with a bolt 66.

  An oil seal 120 is provided between the input shaft 100 and the input side casing 110. On the other hand, a cross roller bearing 220 is provided between the output shaft 200 and the bearing support ring 211 so as to receive a load in a thrust direction or a radial direction. An O-ring 225 is disposed between the output shaft 200 and the mounting plate 212.

  The transmission having the above configuration has the following effects.

  (1) In the case of the first and third embodiments, the processing is relatively simple. This is because, apart from the second embodiment, it is not necessary to form a groove having a repetition number in the inner diameter portions of the first and second outer rollers.

  (2) The assembly is relatively simple and the life of the ball can be extended. This is because it is not necessary to provide a ball entry plug on the ball rolling surface and no step is generated.

  (3) In the first embodiment, when the first and second outer rollers are hollow, it is particularly suitable for constituting a robot arm.

  The present invention can be applied to all speed reducers, and is particularly suitable for use in a drive device that requires precise control, such as a robot arm or an automatic tool changer.

FIG. 1 shows a first example of the first embodiment of the present invention. The relationship between the first endless groove, the second endless groove, and the retainer shown in FIG. 18 is developed in the circumferential direction. Shown in the figure. FIG. 2 shows a second example of the first embodiment of the present invention. The relationship between the first endless groove, the second endless groove, and the retainer shown in FIG. 18 is developed in the circumferential direction. Shown in the figure. FIG. 3 shows a first example of the second embodiment of the present invention. The relationship between the endless groove provided in the inner cylinder, the endless groove provided in the outer cylinder, and the guide cylinder shown in FIG. Is shown in a developed view in the circumferential direction. FIG. 4 shows a second example of the second embodiment of the present invention, and the relationship between the endless groove provided in the inner cylinder, the endless groove provided in the outer cylinder, and the guide cylinder shown in FIG. Is shown in a developed view in the circumferential direction. FIG. 5 shows a first example in the third embodiment of the present invention, and the relationship between the endless groove provided in the driving member shown in FIG. 20, the endless groove provided in the driven member, and the retainer. Is shown with respect to the opposing surface of the driving member and the periphery of the driven member similar to FIG. FIG. 6 shows a second example of the third embodiment of the present invention, and the relationship between the endless groove provided in the driving member shown in FIG. 20, the endless groove provided in the driven member, and the retainer. Is shown with respect to the opposing surface of the drive member and the periphery of the driven member similar to FIG. FIG. 7 is a diagram showing a first example of the shape of the second groove among the first and second grooves shown in FIG. FIG. 8 is a diagram showing a second example of the shape of the second endless groove among the first and second endless grooves shown in FIG. FIG. 9 is a diagram showing a third example of the shape of the second endless groove among the first and second endless grooves shown in FIG. FIGS. 10A to 10C are views showing some examples of the cross-sectional shapes of the first and second endless grooves shown in FIG. FIGS. 11A to 11D are views for explaining another example of the retainer used in the present invention. FIG. 12 is a cross-sectional view for explaining the shape of the ball receiving portion formed on the retainer shown in FIGS. 11 (a) and 11 (b). FIG. 13 is a cross-sectional view for explaining the shape of a ball receiving portion formed on the retainer shown in FIG. FIG. 14 shows an actual machine structure in which a reduction gear according to the present invention is housed in a casing. FIG. 15 is a longitudinal sectional view of a transmission according to a first conventional example. FIG. 16 is a developed view in the circumferential direction showing the relationship between the endless groove provided in the inner cylinder, the endless groove provided in the outer cylinder, and the guide cylinder in the transmission of FIG. FIG. 17 is an external view showing a pivoting ball speed reducer to which the present invention is applied, with the casing removed. FIG. 18 is an exploded view of FIG. FIGS. 19A and 19B show the relationship between the first endless groove, the second endless groove, and the retainer shown in FIG. 18 in a development view in the circumferential direction for the second conventional example. FIG. 20 is a longitudinal sectional view showing a transmission according to a third conventional example. FIG. 21 is a view showing the retainer shown in FIG. FIG. 22 shows the relationship between the endless groove provided in the drive member shown in FIG. 20, the endless groove provided in the driven member, and the retainer with respect to the opposing surfaces of the drive member and the periphery of the driven member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st outer roller 12A 1st endless groove 20 2nd outer roller 22A 2nd endless groove 31,330 Retainer 32,335 Ball 115 Inner cylinder 115a Inclined groove 125 Outer cylinder 125a Sine wave groove 135 Guide cylinder 135a Narrow groove 310 Driving member 320 Driven member 310a, 320a Groove

Claims (8)

A first rotating body having a first endless groove defined by a first number of repetitions Ks on the surface of the first shaft body;
A second rotating body having a second endless groove defined by a second number of repetitions Ks · Ki different from the first number of repetitions Ks on the surface of the second shaft body;
Including at least one groove or slot for holding a ball, and a ball holding portion for coupling the first rotating body and the second rotating body via the ball;
The first repetition number Ks is represented by m / n (where n is a positive integer of 2 or more, m is a positive integer of 1 or more, and n> m), and Ki is an integer of Ks · Ki. The transmission is characterized in that the speed reduction ratio is 1 / Ki or the speed increase ratio, and the number of the grooves or slots is represented by Ks (Ki ± 1) at the maximum. In the first rotating body, the first endless groove is formed in the circumferential direction on the outer peripheral surface of the first shaft body having a circular cross section,
In the second rotating body, the second endless groove is formed in the circumferential direction on the outer peripheral surface of the second shaft body having a circular cross section,
The ball holding portion is a cylindrical body having a plurality of grooves extending in the axial direction at intervals in the circumferential direction on the inner diameter surface, and holds the first and second balls in each groove and slides in the axial direction. Possible retainers are arranged,
The first rotating body and the second rotating body include the first ball positioned in the first endless groove and the second position positioned in the second endless groove. The transmission according to claim 1, wherein each of the transmissions faces the ball holding portion via a ball. In the first rotating body, the first endless groove is formed in the circumferential direction on the outer peripheral surface of the first shaft body having a circular cross section,
In the second rotating body, the second endless groove is formed in the circumferential direction on the inner peripheral surface of a cylindrical body having a circular cross section having a larger diameter than the outer peripheral surface of the first shaft body,
The ball holding portion is a cylindrical body having a plurality of grooves extending in the axial direction at intervals in the circumferential direction, and between the outer peripheral surface of the first shaft body and the inner peripheral surface of the second shaft body. Are placed in each groove to hold the ball,
A part of the ball exposed outward from the ball holding part is in the first endless groove, and a part of the ball exposed inward from the ball holding part is in the second endless groove. 2. The transmission according to claim 1, wherein the first rotating body and the second rotating body are coupled via a ball.   Each of the first and second endless grooves is a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove is apparent when the first number of repetitions Ks = 1/2. 4. The transmission according to claim 2, wherein the transmission is composed of two upper grooves, and the two grooves intersect with each other at an angular position having an amplitude of 0 respectively.   Each of the first and second endless grooves is a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove is apparent when the first number of repetitions Ks = 1/3. It consists of the top three grooves, and two of these three grooves intersect with each other at a first angular position 180 degrees away from the angular position of the maximum amplitude of each of the three grooves, 4. The transmission according to claim 2, wherein one of the two grooves intersects with each other at a second angular position that is 180 ° apart from the first angular position. 5. In the first rotating body, the first endless groove is formed in the circumferential direction on the tip surface of the first shaft body,
In the second rotating body, the second endless groove is formed in the circumferential direction on the distal end surface of the second shaft body facing the distal end surface of the first shaft body,
The ball holding portion is a disc having a plurality of grooves extending in the radial direction at intervals in the circumferential direction, and between the tip surface of the first shaft body and the tip surface of the second shaft body. Arranged to hold the ball in each groove,
A part of the ball exposed to the first shaft body side from the ball holding portion is in the first endless groove, and one of the balls exposed to the second shaft body side from the ball holding portion. 2. The transmission according to claim 1, wherein the first rotating body and the second rotating body are coupled to each other via a ball by having a portion in the second endless groove. .   Each of the first and second endless grooves is a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove is apparent when the first number of repetitions Ks = 1/2. It consists of two upper grooves, and these two grooves intersect with each other at angular positions with zero amplitude, and each groove has a shape symmetrical with respect to the diameter of the disk passing through the angular position. The transmission according to claim 6. Each of the first and second endless grooves is a groove having a periodic function waveform whose amplitude periodically changes, and the first endless groove is apparent when the first number of repetitions Ks = 1/3. It consists of the top three grooves, and two of these three grooves intersect each other at a first angular position 180 degrees apart from the angular position of the maximum amplitude of each of the three grooves, while the remaining one groove And one of the two grooves intersects each other at a second angular position that is 180 ° apart from the first angular position, and each groove passes through the first and second angular positions. The transmission according to claim 6, wherein the transmission has a line-symmetric shape with respect to the diameter of the transmission.

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