JP2009275739A - Ball reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a structure capable of smoothly rotating an eccentric plate 2a and an input shaft 1a regardless of the deviated axial component applied to the eccentric plate 2a, and the moment based on the axial component. <P>SOLUTION: A cylindrical sliding member 43 is provided on an outer peripheral surface of the eccentric plate 2a in the sate of being brought into slidble contact with both of a side surface of a lid body 35 and a side surface of a flange part 28a. The sliding member 43 props between the side surface of the lid body 35 and the side surface of the flange part 28a, and thereby, the axial component and the moment can be supported (removably supported), and the eccentric plate 2a and the input shaft 1a can be smoothly rotated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a ball speed reducer incorporated in various mechanical devices such as an electric power steering device, a steering angle variable steering device, and an industrial robot. Specifically, it intends to expand the possibility of application to the various mechanical devices by facilitating the operation (rotation and torque transmission) of the ball reducer that can obtain a large reduction ratio.

  2. Description of the Related Art Conventionally, a ball speed reducer that can obtain a larger speed reduction ratio than a general gear speed reducer has been known, for example, as described in Patent Documents 1 to 3. 13 to 15 show an example of a conventionally known ball speed reducer described in Patent Document 2 among them. In the case of this conventional structure, the disc-shaped eccentric plate 2 is swung around the casing 3 by the crank-type input shaft 1 (more specifically, the revolving motion around the rotation center axis α of the input shaft 1). , The rotation of the input shaft 1 about the axis β eccentric to the rotation center axis α. Further, epicycloid type or hypocycloid type guide grooves as shown in FIGS. 15A and 15B are formed on opposite side surfaces of the eccentric plate 2 and the fixed plate 4 fixed to the inner surface of the casing 3. 5a and 5b are formed. A plurality of balls 6 and 6 are sandwiched between the guide grooves 5a and 5b. Among these members, the eccentric plate 2 and the fixed plate 4 correspond to a pair of rotation transmitting members described in the claims.

  When the input shaft 1 is rotated, the eccentric plate 2 is decelerated depending on the wave numbers of the both guide grooves 5a and 5b, as described in the sixth column, lines 4 to 9 of Patent Document 2, etc. Depending on the ratio, the input shaft 1 rotates at a lower speed than the rotational speed. Therefore, the rotation of the eccentric plate 2 is taken out by the balls 6 a and 6 a sandwiched between the other side surface of the eccentric plate 2 and the annular grooves 8 a and 8 b formed in the rotary take-out plate 7, and coupled to the rotary take-out plate 7. The fixed output shaft 9 is rotated. In the case of the conventional structure shown in FIGS. 13 to 14, no speed change is performed between the eccentric plate 2 and the output shaft 9. However, as in the structure described in Patent Document 3, for example, a ball speed reducer (ball speed change mechanism) may be provided between the eccentric plate and the rotation takeout plate so that a larger reduction ratio can be obtained. . In this case, the eccentric plate (the second power plate 15 in FIG. 1 of Patent Document 3) and the rotary take-out plate (also the third power plate 18 in FIG. 1 of Patent Document 3) are also described in the claims. It corresponds to a transmission member.

  Moreover, even if it constructs | assembles an electric power steering apparatus by incorporating a ball reduction gear in the steering apparatus for motor vehicles, it is conventionally known by the patent document 4, etc. Furthermore, it is a steering angle variable type steering device incorporating a ball speed reducer, which can be manufactured with a relatively simple structure at a low cost, and, if necessary, based on the minimum necessary steering wheel operation even when the electric motor fails. Japanese Patent Application No. 2007-206603 discloses a structure that can give a required steering angle to a steered wheel. The structure of the prior invention will be described with reference to FIGS.

  The steering angle variable steering apparatus according to the present invention includes an input shaft 10, an output shaft 11, an intermediate rotating cylinder 12, an electric motor 13, an eccentric plate 14, a first ball transmission mechanism 15, and a second ball transmission. Mechanism 16. Of these, the input shaft 10 is the first rotating shaft described in the claims, the output shaft 11 is the same as the second rotating shaft, the intermediate rotating cylinder 12 is the same as the intermediate rotating shaft, and the eccentric plate 14 is the same as the rotation transmitting member. Or the intermediate rotation transmission member, the first ball speed change mechanism 15 is also equivalent to the ball speed reducer or the first speed reduction mechanism, and the second ball speed change mechanism 16 is also equivalent to the ball speed reducer or the second speed reduction mechanism. To do. The input shaft 10 is rotatably supported on the inner diameter side of the steering column 17 and rotates as the steering wheel 18 rotates. The input shaft end of the output shaft 11 is coupled and fixed to the other end of the steering column 17 so that the input shaft 10 is concentric with the input shaft 10 and can freely rotate relative to the input shaft 10. I support it.

  The intermediate rotary cylinder 12 is disposed in the housing 19 between the input shaft 10 and the output shaft 11, concentric with the input shaft 10 and the output shaft 11, and the input shaft 10 and the output shaft. 11 is supported so as to be capable of relative rotation. The intermediate rotating cylinder 12 being concentric with the input shaft 10 and the output shaft 11 is a state based on the outer peripheral surface of the intermediate rotating cylinder 12. In the case of the structure of the previous invention, the intermediate rotating cylinder 12 is a crank-shaped section and is formed in a stepped cylinder as a whole. In such an intermediate rotating cylinder 12, the small diameter portion 20 is rotatably supported on the outer peripheral surface of the output shaft 11.

  The intermediate rotating cylinder 12 as described above can be driven to rotate at a desired rotational speed in a desired direction by the electric motor 13 installed in the housing 19. In addition, a steering angle sensor 21 for obtaining the rotation angle of the input shaft 10 is provided at the upper end portion of the steering column 17, and control is performed between the outer peripheral surface of the small diameter portion 20 and the inner surface of the lower end portion of the housing 19. A rotation angle sensor 22 is provided. With this configuration, the intermediate rotary cylinder 12 can be driven to rotate while appropriately regulating the rotation speed at a desired rotation speed in a desired direction.

  Further, the thickness in the radial direction of the large diameter portion 23 constituting the intermediate rotating cylinder 12 is gradually changed in the circumferential direction, and the central axis of the inner peripheral surface of the large diameter portion 23 is set as the input shaft 10 and the above The output shaft 11 is eccentric. The eccentric plate 14 is rotatably supported on the inner diameter side of the large diameter portion 23. With such a configuration, the eccentric plate 14 can be rotated around a central axis β that is parallel to the input shaft 10 and the output shaft 11 and eccentric with respect to both the shafts 10, 11. The cylinder 12 is supported on the inner diameter side.

  Further, the first ball transmission mechanism 15 and the second ball transmission mechanism 16 are provided between both axial side surfaces of the eccentric plate 14 and the input shaft 10 and the output shaft 11. Of these, the first ball transmission mechanism 15 transmits the rotation from the input shaft 10 to the eccentric plate 14 and the second ball transmission mechanism 16 transmits the rotation from the eccentric plate 14 to the output shaft 11 while reducing the rotation. It is possible. Further, the rotational speed ratio between the input shaft 10 and the output shaft 11 can be adjusted by adjusting the rotational direction and rotational speed of the eccentric plate 14 by the electric motor 13.

  In order to constitute the first ball transmission mechanism 15 of the both ball transmission mechanisms 15, 16, a drive ring 24, which is a first rotation transmission member described in the claims, is coupled to the tip of the input shaft 10. It is fixed. An input shaft side guide groove 25, which is the first rotation transmission member side guide groove of the claims, is formed on the end face of the drive ring 24 in the axial direction opposite to the eccentric plate 14. Yes. Further, of the axially opposite side surfaces of the eccentric plate 14, an axial one side surface portion opposed to the input shaft side guide groove 25 is an intermediate rotation transmission member side first guide groove described in claims. An eccentric plate input side guide groove 26 is formed. These guide grooves 25 and 26 have the same pitch circle diameter. The center of the pitch circle of the input shaft side guide groove 25 exists on the center axis α of the input shaft 10, and the center of the pitch circle of the eccentric plate input side guide groove 26 is the rotation center axis of the eccentric plate 14. exists on β. In the case of the structure of the previous invention, as shown in FIG. 18A, the input shaft side guide groove 25 has an epicycloid shape, and the eccentric plate input side guide groove 26 has a hypocycloid shape. The shapes of both guide grooves 25 and 26 may be reversed.

  In any case, the wave number of the epicycloid-shaped guide groove is two less than the wave number of the hypocycloid-shaped guide groove. In the case of the structure of the prior invention, the wave number of the eccentric plate input side guide groove 26 having a hypocycloid shape is N, and the wave number of the input shaft side guide groove 25 having an epicycloid shape is "N-2". . A portion where the eccentric plate input side guide groove 26 and the input shaft side guide groove 25 overlap with each other in the axial direction of the eccentric plate 14 between the eccentric plate input side guide groove 26 and the input shaft side guide groove 25. In addition, “N−1” input side balls 27, 27 are arranged.

  Of the flange portion 28, which is the second rotation transmission member described in the claims, formed in the portion near the proximal end of the output shaft 11 to constitute the second ball transmission mechanism 16, the eccentric plate 14 is formed with an output shaft side guide groove 29 which is the second rotation transmission member side guide groove described in the claims. Further, the second guide groove on the intermediate rotation transmission member side described in the claims is formed on the other side surface portion in the axial direction opposite to the output shaft side guide groove 29 among both side surfaces in the axial direction of the eccentric plate 14. An eccentric plate output side guide groove 30 is formed. These guide grooves 29 and 30 have the same pitch circle diameter. The center of the pitch circle of the output shaft side guide groove 29 exists on the center axis α of the output shaft 11, and the center of the pitch circle of the eccentric plate output side guide groove 30 is the rotational axis β of the eccentric plate 14. Exists on. In the case of the structure of the prior invention, as shown in FIG. 18B, the output shaft side guide groove 29 has an epicycloid shape, and the eccentric plate output side guide groove 30 has a hypocycloid shape. The shapes of the guide grooves 29 and 30 may be reversed.

  In any case, the wave number of the epicycloid-shaped guide groove is two less than the wave number of the hypocycloid-shaped guide groove. In the case of the structure of the previous invention, the wave number of the eccentric plate output side guide groove 30 having a hypocycloid shape is M, and the wave number of the output shaft side guide groove 29 having an epicycloid shape is "M-2". . A portion where the eccentric plate output side guide groove 30 and the output shaft side guide groove 29 overlap with each other in the axial direction of the eccentric plate 14 between the eccentric plate output side guide groove 30 and the output shaft side guide groove 29. In addition, “M−1” output side balls 31 are arranged. The wave number N of the eccentric plate input side guide groove 26 and the wave number M of the eccentric plate output side guide groove 30 are different from each other (N ≠ M). Further, a preload is applied to each of the output side balls 31 and 31 and each of the input side balls 27 and 27 based on tightening of a nut 32 screwed to an end portion of the output shaft 11, and each of the balls 27 and 31 and the guide grooves 25, 26, 29, and 30 are not rattling.

Each of which has a configuration as described above and includes a ball speed reducer 33 composed of the first ball transmission mechanism 15 and the second ball transmission mechanism 16 which are combined via the intermediate rotating cylinder 12. In the case of the steering angle variable type steering apparatus of the invention, the rotation speed ratio (relative angle) between the input shaft 10 and the output shaft 11 can be freely changed by the rotation control of the intermediate rotating cylinder 12. For example, with the steering wheel 18 held and the input shaft 10 fixed, the number of rotations of the intermediate rotating cylinder 12 during one rotation of the output shaft 11 is expressed as a reduction ratio K of the ball reducer 33. If so, the reduction ratio K can be freely designed as will be described later. On the other hand, when the steering wheel 18 is operated and the input shaft 10 rotates, the relationship expressed by the following equation (1) is established, assuming that the entire mechanism rotates.
_{K = (N 12 -N 10)} / (N 11 -N 10) --- (1)
Reference numerals N ₁₀ , N ₁₁ , and N ₁₂ in the expression (1) represent the rotation speed or rotation angle of the input shaft 10, the output shaft 11, and the intermediate rotating cylinder 12, respectively.

On the other hand, the reduction ratio K is a designable constant determined by the wave numbers of the guide grooves 25, 26, 29, and 30. In consideration of these matters, when the rotation speed or rotation angle N _{10 of the} input shaft 10 is determined, the rotation speed or rotation angle N ₁₂ of the intermediate rotating cylinder ₁₂ is appropriately adjusted to thereby adjust the output shaft 11. It can be seen that the rotation speed or rotation angle N ₁₁ can be adjusted arbitrarily. That is, the steering angle variable type steering device having the structure of the previous invention has a structure in which the rotational speed ratio (relative angle) between the input shaft 10 and the output shaft 11 can be freely changed.

For example, consider the case where the rotation speed or rotation angle N ₁₂ of the intermediate rotating cylinder 12 is set as shown in the following equation (2).
N ₁₂ = {K (k−1) +1} N ₁₀ −−− (2)
By substituting this equation (2) into the above equation (1), the following equation (3) can be obtained.
N ₁₁ = k · N ₁₀ −−− (3)
As is clear from this equation (3), the rotational speed or the rotational angle N ₁₂ of the intermediate rotary cylinder 12 By restricting as described above (2), the structure of the preceding invention, the steering angle of the steering ratio k It becomes a variable steering device. In addition, it is possible to freely control the rotation speed or rotation angle N ₁₁ of the output shaft 11 by operating the rotation speed or rotation angle N ₁₂ of the intermediate rotating cylinder 12 by the electric motor 13. Furthermore, it is also possible to perform an operation of detecting a side slip or spin of the vehicle and automatically giving a corrected rudder (counter steer).

In the case of the structure of the previous invention, the following configurations (a) and (b) are provided so that the rotation of the input shaft 10 can be transmitted to the output shaft 11 even when the electric motor 13 fails. I have them together.
(a) The reduction ratio K of the ball speed reducer 33 including the both ball transmission mechanisms 15 and 16 is set high (for example, about 20 to 100).
(b) Contact portions of the eccentric plate input side guide groove 26 and the input shaft side guide groove 25 and the input side balls 27 and 27, and the eccentric plate output side guide groove 30 and the output shaft side guide groove 29 and the output side balls 31, 31 are set to have a large slip factor. In the case of this example, in order to perform such a setting, the cross-sectional shape of each of the guide grooves 26, 25, 30, 29 is a Gothic arch shape as shown in FIG. More specifically, the rest angle θ between each of the guide grooves 26, 25, 30, 29 and the balls 27, 31 is set to 25 to 60 degrees, and the groove R ratio (the guide grooves 26, 25, 30 are the same). 29, the radius of curvature R / the diameter Da of each of the balls 27 and 31 is set in the range of 0.505 to 0.54.
Then, by combining the above-described configurations (a) and (b), the electric motor 13 does not drive the intermediate rotating cylinder 12 and the force in the revolving motion direction is applied to the eccentric plate 14 from the outside. In this state, the eccentric plate 14 and the input shaft 10 and the output shaft 11 are rotated synchronously (the ball speed reducer 33 is self-locked).

  Even if the ball speed reducer 33 constituting the steering angle variable type steering apparatus of the above-described prior invention or the ball speed reducer having the conventional structure shown in FIGS. It is not performed through all the balls 6, 27, 31 (the torque is transmitted through some of the balls 6, 27, 31). For this reason, the eccentric plates 2 and 14, which are rotation transmission members, the drive ring 24, and the flange portion 28, are partially biased from the balls 6, 27 and 31, and are not uniform in the circumferential direction of the rotation transmission member. And a moment about the radial direction as an axis may be applied to the eccentric plates 2, 14, the drive ring 24, and the flange portion 28 based on such an axial component force. Such a moment makes the rotating shafts rotating together with the eccentric plates 2, 14, the drive ring 24, and the flange 28, that is, the rotational states of the input shafts 1, 10, the output shaft 11, and the intermediate rotating cylinder 12 unstable ( It may be difficult to rotate smoothly), and vibration may occur with torque transmission or torque transmission may not be performed smoothly. Such inconvenience is not preferable, for example, when it is incorporated in a steering angle variable type steering apparatus, which causes a driver to operate the steering wheel.

Japanese Patent Publication No. 1-2378 Japanese Examined Patent Publication No. 7-62495 JP 2003-172419 A Japanese Patent Laid-Open No. 2003-261048

  In view of the circumstances as described above, the ball speed reducer according to the present invention includes the rotation transmission member and the rotation regardless of the biased axial component force applied to the rotation transmission member and, therefore, the moment based on the axial component force. The present invention has been invented to realize a structure that can smoothly rotate a member that rotates together with a transmission member.

The ball speed reducer of the present invention is a ball speed reducer (first and second speed reduction mechanisms, first and second speed speed reduction mechanisms, which have been conventionally known or incorporated in the steering angle variable type steering device of the previous invention. Similar to the ball speed change mechanism), at least one pair of rotation transmission members, a guide groove, and a plurality of balls are provided.
Each of these rotation transmitting members rotates relative to each other while being eccentrically arranged in parallel with each other.
The guide grooves are formed on at least one pair of axial side surfaces facing each other of the rotation transmission members, and have a cycloid wave shape or a trochoidal wave shape.
The balls are sandwiched between the guide grooves.
In particular, in the ball speed reducer according to the present invention, the rotation transmission members of the pair of rotation transmission members are in sliding contact with the other rotation transmission member and the balls. Also supports a sliding member having low rigidity.

  In addition, if necessary, in addition to the configuration of providing the sliding member as described above, or instead of the configuration of providing such a sliding member (without providing the sliding member), The pitch circle diameter (PCD) of the rolling bearing for supporting one rotation transmission member of the pair of rotation transmission members so as to freely swing around (revolution movement) is also set to the guide groove of the other rotation transmission member. The length (distance) between the contact point located on the outermost side in the radial direction among the contact portions (rolling contact portions) with each of the balls and the swing center (center of revolution motion) of the one rotation transmission member It is also possible to adopt a configuration that is larger than twice the above.

  Also, if necessary, along with at least one of the configuration in which the sliding member as described above is provided and the configuration in which the pitch circle diameter (PCD) is regulated as described above, or Instead of both of these configurations {without providing a sliding member and without restricting the pitch circle diameter (PCD) as described above}, each of the rotation transmission members and the members that rotate together with these rotation transmission members It is also possible to adopt a configuration in which a thinning part is provided in at least one of the above. Such a thinned portion can be configured by, for example, providing a through hole (through hole) in a state where it penetrates in the axial direction of the rotation transmission member in a portion of the side surface of the rotation transmission member that is removed from the guide groove. . Moreover, it can also comprise by providing a ditch | groove over the circumferential direction of this rotation transmission member in the state recessed from the side surface of this rotation transmission member. In addition, when providing this recessed groove, it is more preferable to provide in the part which remove | deviated from the said guide groove to the radial direction outer side among the side surfaces of the said rotation transmission member. The reason for this is that the length of the concave groove can be increased, and the amount of thinning can be increased correspondingly as compared with the case where the groove is provided at a portion that is radially inward.

In any case, when the ball speed reducer of the present invention as described above is implemented, the ball speed reducer is preferably composed of the first speed reduction mechanism and the second speed reduction mechanism as in the invention described in claim 2.
Of these, the first speed reduction mechanism portion includes a disk-shaped intermediate rotation transmission member having guide grooves formed on both side surfaces in the axial direction, and a first rotation transmission member facing one axial side surface of the intermediate rotation transmission member. The first rotation transmission member side guide groove formed on the end surface and the intermediate rotation transmission member side guide groove formed on one side surface in the axial direction of the intermediate rotation transmission member so as to face the first rotation transmission member side guide groove. And a plurality of first balls sandwiched between the first rotation transmission member side first guide groove and the first rotation transmission member side guide groove.
In addition to the intermediate rotation transmission member, the second speed reduction mechanism portion includes a second rotation transmission member side guide groove formed on an end surface of the second rotation transmission member facing the other axial side surface of the intermediate rotation transmission member. And an intermediate rotation transmission member-side second guide groove formed on the other side surface in the axial direction of the intermediate rotation transmission member so as to face the second rotation transmission member-side guide groove, and the intermediate rotation transmission member-side second And a plurality of second balls sandwiched between the guide groove and the second rotation transmission member side guide groove.

The sliding member supported by the intermediate rotation transmission member is brought into sliding contact with at least one of the first and second rotation transmission members.
Further, if necessary, the pitch circle diameter (PCD) of the rolling bearing for supporting the intermediate rotation transmission member so as to freely swing (revolve) is set to the first rotation transmission member side guide groove and the first rotation groove. Of the contact portions (rolling contact portions) with each ball, the contact point located on the outermost radial direction, or the contact portion (rolling contact portion) between the second rotation transmission member side guide groove and each second ball Is set to be larger than twice the length (distance) between the contact point located on the outermost side in the center and the center of swinging of the intermediate rotation transmission member (center of revolution).

  Further, if necessary, at least one of the intermediate rotation transmission member, the first and second rotation transmission members, and a member that rotates together with each of the rotation transmission members is provided with a wall removal portion. In this case, the said thinning part can be comprised by providing a through-hole (through-hole) in the state which penetrates the axial direction both sides | surfaces of the said intermediate rotation transmission member in this case, for example. In this case, for example, on the side surface of the intermediate rotation transmission member, a plurality of the through-holes (through holes) are formed in a portion that is radially removed from the first and second guide grooves on the intermediate rotation transmission member side. It can be provided in a state of being spaced apart in the circumferential direction (for example, at equal intervals in the circumferential direction). Further, each of these through holes (through holes) is one of the radial rotation inner side and the radial direction outer side of the intermediate rotation transmission member side first and second guide grooves of the intermediate rotation transmission member, or Can be provided on both sides. In addition, the intermediate rotation transmission member is inserted into the intermediate rotation transmission member on both sides in the axial direction, with the intermediate rotation transmission member side first and second guide grooves being radially displaced from the side surface. By providing the concave groove over the entire circumference of the rotation transmitting member, the above-described thinned portion can be configured. In this case, the groove provided on the outer side in the radial direction of the first and second guide grooves on the intermediate rotation transmission member side can be made longer than the groove provided on the inner side in the radial direction. The meat volume can be increased. Furthermore, the said thinning part can also be comprised by providing a concave groove like a key groove in the member rotated with the said intermediate rotation transmission member.

In any case, when the ball speed reducer of the present invention described in claim 2 as described above is incorporated in the steering angle variable type steering apparatus shown in FIGS. As in the invention described in, the first rotation transmission member is rotated together with the first rotation shaft. The intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove have a cycloid wave shape or a trochoidal wave shape along the pitch circle having the same diameter, and the central axis of the intermediate rotation transmission member And the center axis of the first rotating shaft are offset from each other by an amount of eccentricity.
At the same time, the second rotation transmission member is rotated together with the second rotation shaft. The intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove have a cycloidal wave shape or a trochoidal wave shape along the pitch circle having the same diameter, and the center of the intermediate rotation transmission member The shaft and the center axis of the second rotating shaft are eccentric from each other by the amount of eccentricity.
Further, the wave number of the intermediate rotation transmission member side first guide groove and the wave number of the intermediate rotation transmission member side second guide groove are different from each other.

Further, when the ball speed reducer of the present invention described in claim 2 and claim 3 described above is implemented, the intermediate rotation transmission member is preferably connected to the intermediate rotation shaft as in the invention described in claim 4. Rotating motion (more specifically, rotating around the rotation center axis of the intermediate rotation shaft while rotating around the rotation center axis of the intermediate rotation shaft) )It shall be. The intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove have a cycloid wave shape or a trochoidal wave shape along a pitch circle having the same diameter, and the center of the intermediate rotation transmission member They are decentered from each other by the amount of eccentricity between the shaft (center axis of rotation) and the center axis of rotation of the intermediate rotation shaft (center axis of revolution).
At the same time, the second rotation transmission member is rotated together with the second rotation shaft. The intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove have a cycloidal wave shape or a trochoidal wave shape along the pitch circle having the same diameter, and the center of the intermediate rotation transmission member The shaft and the center axis of the second rotating shaft are eccentric from each other by the amount of eccentricity.
Further, the wave number of the intermediate rotation transmission member side first guide groove and the wave number of the intermediate rotation transmission member side second guide groove are different from each other.

When the ball transmission of the present invention as described above is implemented, more specifically, as in the invention described in claim 5, the intermediate rotation transmission member side first guide groove and the first rotation transmission member side. One of the guide grooves is a hypocycloid shape or a hypotrochoid shape having a wave number of N. Similarly, the other guide groove has an epicycloid shape or an epitrochoid shape having a wave number of “N-2”. The intermediate rotation transmission member-side first guide groove and the first rotation transmission between the intermediate rotation transmission member-side first guide groove and the first rotation transmission member-side guide groove with respect to the axial direction of the intermediate rotation transmission member. “N−1” balls are arranged in a portion where the member side guide groove overlaps.
In addition, one of the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove is formed into a hypocycloid shape or a hypotrochoid shape having a wave number of M. Similarly, the other guide groove has an epicycloid shape or an epitrochoid shape with a wave number of “M-2”. And between the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove, the intermediate rotation transmission member side second guide groove and the second rotation with respect to the axial direction of the intermediate rotation transmission member. “M−1” balls are arranged in a portion where the transmission member side guide groove overlaps.

According to the present invention configured as described above, a biased axial component force (a non-uniform axial load with respect to the circumferential direction of the rotation transmission member) applied to the rotation transmission member, and a moment based on this axial component force ( The rotation transmitting member and the member that rotates together with the rotation transmitting member can be smoothly rotated regardless of the moment about the radial direction).
That is, the sliding member provided between the rotation transmitting members stretches between the rotation transmitting members in the axial direction. For this reason, the sliding member can ensure the rigidity in the axial direction, and thus the rigidity against the moment (torsional rigidity), and can rotate together with the rotation transmission member and the rotation transmission member regardless of the axial component force and moment. The member to be rotated can be smoothly rotated (stable rotation). As a result, it is possible to perform smooth torque transmission while suppressing vibration associated with torque transmission. For example, when incorporated in a steering angle variable type steering device, it is possible to prevent the driver operating the steering wheel from feeling uncomfortable. .

  Further, the pitch circle diameter (PCD) of the rolling bearing for supporting the rotation transmission member so as to freely swing around (revolution movement) is set to the most radial direction among the contact portions (rolling contact portions) between the guide groove and each ball. If the length is greater than twice the length (distance) between the contact point located outside and the center of rotation of the rotation transmission member (center of revolution), the rigidity of the rolling bearing can be sufficiently secured. Thus, it is possible to prevent a decrease in the preload applied to each ball. That is, if the pitch circle diameter (PCD) of the rolling bearing is small, there is a possibility that sufficient rigidity of the rolling bearing cannot be secured. In such a case, based on the axial component force and moment, the preload applied to each of the balls is likely to decrease (preload loss is likely to occur), and the rotation transmission member and the rotation transmission member rotate together. There is a possibility that the member to be rotated cannot be smoothly rotated (vibration occurs with torque transmission or torque transmission cannot be smoothly performed). On the other hand, when the pitch circle diameter (PCD) is regulated as described above, the rigidity of the rolling bearing, that is, the rigidity with respect to the moment (torsional rigidity) is sufficiently secured, regardless of the moment. The rotation transmitting member and the member rotating together with the rotation transmitting member can be smoothly rotated (stable rotation). As a result, it is possible to perform smooth torque transmission while suppressing vibration associated with torque transmission. For example, when incorporated in a steering angle variable type steering device, it is possible to prevent the driver operating the steering wheel from feeling uncomfortable. .

  Further, if a thinning portion is provided in at least one of the rotation transmission members and the members that rotate together with the rotation transmission members, the rotation transmission member and a counterweight attached to the rotation transmission member {add to the rotation transmission member The centrifugal force can be made uniform in the circumferential direction, the weight for stabilizing the rotation (revolution and rotation) of the rotation transmission member can be reduced, and the centrifugal force applied to the entire rotation transmission member can be reduced. That is, the greater the weight of the rotation transmission member, the greater the weight of the counterweight and the greater the centrifugal force applied to the entire rotation transmission member. If the centrifugal force increases in this way, it is necessary to ensure the rigidity of a rolling bearing or the like for supporting the rotation transmission member, and vibrations associated with rotation may be easily increased. . On the other hand, when the thinning portion is provided as described above, the rotation transmission member and the counterweight can be reduced in weight and the centrifugal force can be reduced, and accordingly, the rigidity of the rolling bearing can be easily secured. At the same time, the vibration associated with the rotation can be reduced. Moreover. The entire ball reducer can be configured to be lightweight. In addition, the rotation transmission member and the member that rotates together with the rotation transmission member can be smoothly rotated (stable rotation) regardless of the axial component force and moment because the rigidity of the rolling bearing is easily secured. As a result, it is possible to perform smooth torque transmission while suppressing vibration associated with torque transmission. For example, when incorporated in a steering angle variable type steering device, it is possible to prevent the driver operating the steering wheel from feeling uncomfortable. .

[Example of Embodiment]
FIG. 1 shows an example of an embodiment of the present invention corresponding to claims 1, 2, 4, and 5. In the case of this example, similarly to the ball speed reducer described in Patent Document 3, the ball speed reducer described in the claims or the first ball speed change mechanism 15a corresponding to the first speed reduction mechanism section is the same. A ball speed reducer or a second ball speed change mechanism 16a corresponding to a second speed reduction mechanism. Among these, the first ball transmission mechanism 15a includes an eccentric plate 2a corresponding to a rotation transmission member or an intermediate rotation transmission member described in the claims, and a stationary side corresponding to the first rotation transmission member side guide groove. A guide groove 34, an eccentric plate input side guide groove 26a corresponding to the intermediate rotation transmission member side first guide groove, and a plurality of input side balls 27a and 27a each corresponding to the first ball are also provided. Of these, the eccentric plate 2a is formed with the eccentric plate input side guide groove 26a on one axial side surface (right side surface in FIG. 1) and on the other axial side surface (left side surface in FIG. 1). The disc-shaped member is formed with an eccentric plate output side guide groove 30a corresponding to the intermediate rotation transmission member side second guide groove.

  The eccentric plate 2a is swung in accordance with the rotation of the input shaft 1a corresponding to the intermediate rotation shaft described in the claims. Therefore, in the case of this example, the input shaft 1a is rotatably supported by the first rolling bearing 36 on the lid 35 corresponding to the first rotation transmission member described in the claims. The eccentric plate 2a is supported by a second rolling bearing 38 on an eccentric shaft 37 having a central axis β that is eccentric with respect to the rotational central axis α of the input shaft 1a, provided in the middle portion of the shaft 1a. With such a configuration, the eccentric plate 2a can revolve around the rotation center axis α of the input shaft 1a, and can rotate around the center axis β of the eccentric shaft 37. The lid 35 is supported. The lid body 35 constitutes a stationary member that does not rotate together with the bottomed cylindrical casing 3 a whose opening is closed by the lid body 35.

  The stationary side guide groove 34 is formed on the side surface of the lid 35 provided in a state facing the one axial side of the eccentric plate 2a so as to face the eccentric plate input side guide groove 26a. Yes. The input side balls 27a and 27a are sandwiched between the stationary side guide groove 34 and the eccentric plate input side guide groove 26a. The structure of the stationary side guide groove 34, the eccentric plate input side guide groove 26a, and each of the input side balls 27a and 27a is, for example, the steering angle variable type steering according to the prior invention shown in FIGS. The configuration of the input shaft side guide groove 25, the eccentric plate input side guide groove 26, and the input side ball 27a of the first ball transmission mechanism 15 constituting the apparatus can be made the same. That is, the configuration of the input side guide groove 24, the eccentric plate input side guide groove 26, and the input side ball 27 described in the above paragraphs [0010] to [0011] is the same as the stationary side guide groove 34 and the eccentricity of this example. This can correspond to the configuration of the plate input side guide groove 26a and the input side ball 27a.

  In addition to the eccentric plate 2a, the second ball transmission mechanism 16a includes an output shaft side guide groove 29a corresponding to the second rotation transmission member side guide groove described in the claims, and the eccentric plate output side guide. The groove 30a includes a plurality of output side balls 31a and 31a each corresponding to the second ball described in the claims. Of these, the output shaft side guide groove 29a corresponds to the same second rotation transmission member provided at one end portion (the right end portion in FIG. 1) of the output shaft 9a corresponding to the second rotation shaft described in the claims. It is formed on the side surface of the flange portion 28a to face the eccentric plate output side guide groove 30a. The output shaft 9a is rotatably supported on the cylindrical portion 40 of the casing 3a by a third rolling bearing 39, and the other end (the left end in FIG. 1) is placed on the bottom 41 of the casing 3a. Through the through-hole 42 provided in the center, it protrudes from the bottom 41 to the other side in the axial direction (left side in FIG. 1). The output side balls 31a and 31a are sandwiched between the output shaft side guide groove 29a and the eccentric plate output side guide groove 30a.

  In addition, regarding the configurations of the output shaft side guide groove 29a, the eccentric plate output side guide groove 30a, and the output side balls 31a and 31a, for example, the steering angle according to the above-described invention shown in FIGS. The configuration of the output shaft side guide groove 29, the eccentric plate output shaft side guide groove 30 and the output side ball 31a of the second ball transmission mechanism 16 constituting the variable steering device can be made the same. That is, the configuration of the output shaft side guide groove 29, the eccentric plate output side guide groove 30 and the output side ball 31 described in the above paragraphs [0012] to [0013] is the output shaft side guide groove 29a of this example. And the configuration of the eccentric plate output side guide groove 30a and the output side ball 31a. In any case, regarding the basic configuration of the ball speed reducer 33a of this example (the ball speed reducer 33a including both the first and second ball speed change mechanisms 15a and 16a), the prior invention shown in FIGS. In addition to the ball-type transmission 33 that constitutes the steering angle variable type steering apparatus according to the present invention, the other basic configuration is described in detail in the above-mentioned Patent Document 3, and therefore further explanation is omitted.

  In particular, in the case of the ball speed reducer 33a of the present example, a split type such as a two-part split type that is in sliding contact with both the side surface of the lid 35 and the side surface of the flange 28a on the outer peripheral surface of the eccentric plate 2a. Thus, the sliding member 43 that is cylindrical in the combined state (or is divided into a plurality of parts in the circumferential direction and arranged intermittently) is supported and fixed by a plurality of bolts 44 and 44. The sliding member 43 has a lower rigidity than the eccentric plate 2a, the lid 35, the flange portion 28a, the input side and the output side balls 27a and 31a. For example, copper or a copper alloy, It is made of a non-ferrous metal having self-lubricating property, an oil-containing metal, or a synthetic resin having compression resistance such as a high-performance resin. Further, in order to bring the opening peripheral edge of the sliding member 43 into sliding contact with the side surface of the lid 35 and the side surface of the flange portion 28a over the entire circumference, in this example, the sliding member 43 in a state where a predetermined preload is applied to the first and second ball transmission mechanisms 15a and 16a (the connecting bolts 45 and 45 for connecting the lid 35 and the casing 3a are provided with a predetermined torque). The distance (distance) L in the axial direction between the side surface of the lid body 35 and the side surface of the flange portion 28a is substantially the same. More specifically, the axial dimension of the sliding member 43 is the same as the interval (distance) L between the side surfaces or within a range in which the rotational resistance associated with the sliding contact of the sliding member 43 can be allowed ( (Very slightly) larger.

In the case of this example configured as described above, a biased axial component force (a non-uniform axial load in the circumferential direction of the eccentric plate 2a) applied to the eccentric plate 2a during torque transmission, and eventually this axial component force The eccentric plate 2a and the input shaft 1a can be smoothly rotated regardless of the moment based on the moment (the moment about the radial direction).
That is, the sliding member 43 provided on the outer peripheral surface of the eccentric plate 2a and slidably in contact with both the side surface of the lid 35 and the side surface of the flange portion 28a stretches in the axial direction between these both side surfaces. For this reason, the sliding member 43 can sufficiently ensure the rigidity in the axial direction of the first and second ball transmission mechanisms 15a, 16a, and thus the rigidity against the moment (torsional rigidity). In addition, the eccentric plate 2a and the input shaft 1a can be smoothly rotated regardless of the moment (the rotation is stabilized). As a result, it is possible to perform smooth torque transmission while suppressing vibration associated with torque transmission. For example, when incorporated in a steering angle variable type steering device, it is possible to prevent the driver operating the steering wheel from feeling uncomfortable. .

The ball-type transmission 33 constituting the steering angle variable type steering apparatus according to the prior invention shown in FIGS. 16 to 19 described above is configured such that the ball-type transmission 33a of this example is a differential mechanism having no fixed portion. Used (incorporated). That is, the casing 3a and the lid 35 of the present example correspond to the input shaft 10 of the steering angle variable steering apparatus according to the previous invention shown in FIGS. 16 to 19, and the output shaft 9a of the present example is also the same as the output shaft. 11 and the input shaft 1a and the eccentric shaft 37 of this example also correspond to the intermediate rotary cylinder 12 (the eccentric plate 14 is eccentrically moved from the outer diameter side by the intermediate rotary cylinder 12). In the case where the above-described sliding member 43 of this example is incorporated in the ball speed reducer 33 constituting the steering angle variable type steering apparatus according to the prior invention shown in FIGS. 16 to 19, the outer peripheral surface of the eccentric plate 14. The sliding member 43 is supported and fixed to both ends of the sliding member 43 in the axial direction, and the side surface of the drive ring 24 that rotates together with the input shaft 10 and the side surface of the flange portion 28 that rotates together with the output shaft 11. And slidably contact each other.
In the case of implementing this example, the input shaft 1a and the output shaft 9a can be reversed from the case of the illustrated example.

[First example of reference example of the present invention]
2-4 has shown the 1st example of the reference example regarding this invention. In the case of the example of the embodiment described above, the sliding member 43 (see FIG. 1) is provided on the eccentric plate 2a, whereas in the case of this example, such a sliding member 43 is provided. Not. In the case of this reference example, the first rolling bearing 36a for supporting the input shaft 1b on the lid 35a {the first rolling bearing 36a for supporting the eccentric plate 2a in a swinging motion (revolving motion)}. The pitch circle diameter (PCD) is made larger than the structure of the example of the above-described embodiment. Specifically, the pitch circle diameter (PCD) of the first rolling bearing 36a is set to the outermost radial direction of the contact portions (rolling contact portions) between the stationary guide groove 34 and the input side balls 27a and 27a. It is larger than twice the length (distance) between the position of the contact point and the center of swinging of the eccentric plate 2a (center of revolution). In other words, as shown in FIG. 3, the contact angle with respect to the contact point S located on the outermost side in the radial direction among the contact portions (rolling contact portions) between the stationary guide grooves 34 and the respective input side balls 27a is defined as θ. When the radius of each input side ball 27a is dw, the pitch circle diameter (PCD) of the first ball transmission mechanism 15a is PCD _15a, and the pitch circle diameter (PCD) of the first rolling bearing 36a is PCD _36a. PCD _36a > PCD _15a + 2dw · sin θ (The pitch circle of the first rolling bearing 36a is positioned radially outward over the entire circumference from the maximum contact circle of the first ball transmission mechanism 15a. )

FIG. 4 shows the reaction force (torsional torque) of the first ball transmission mechanism 15a with the input shaft 1b fixed at a predetermined angle (predetermined input angle) as a pitch circle of the first rolling bearing 36a. The result of the numerical analysis calculated by the relationship between the ratio of the diameter PCD _15a and the maximum contact diameter (PCD _15a + 2dw · sin θ) is shown. In FIG. 4, “torque” is the reaction force, “bearing PCD” is the pitch circle diameter PCD _15a of the first rolling bearing 36a, and “ball reducer contact point maximum diameter” is the maximum contact diameter ( PCD _15a + 2dw · sin θ). As apparent from FIG. 4, the reaction force (torsion torque) of the first ball transmission mechanism 15a increases as the pitch circle diameter (PCD) of the first rolling bearing 36a increases.

In the case of this reference example, as is clear from the calculation result of FIG. 4, the first ball bearing mechanism 15a is sufficiently secured with sufficient rigidity (torsional torque) of the first rolling bearing 36a. In addition, it is possible to prevent a decrease in preload applied to the input side and output side balls 27a and 31a of the second ball transmission mechanism 16a. That is, if the pitch circle diameter (PCD _36a ) of the first rolling bearing 36a is small, the rigidity of the first rolling bearing 36a may not be sufficiently secured. In such a case, an eccentric axial component force applied to the eccentric plate 2a during torque transmission (a non-uniform axial load with respect to the circumferential direction of the eccentric plate 2a), and then a moment (radial direction) based on this axial component force The preload applied to the input side and output side balls 27a and 31a is likely to be reduced (preload loss is likely to occur), and the eccentric plate 2a and the input shaft 1b are rotated. May not be able to be performed smoothly (vibration may occur with torque transmission or torque transmission may not be performed smoothly). On the other hand, in the case of this reference example in which the pitch circle diameter (PCD _36a ) of the first rolling bearing 36a is regulated as described above, the rigidity of the first rolling bearing 36a, that is, the rigidity against the moment ( (Torsional rigidity) is sufficiently secured, and the eccentric plate 2a and the input shaft 1b can be smoothly rotated (stable rotation) regardless of this moment. As a result, it is possible to perform smooth torque transmission while suppressing vibration associated with torque transmission. For example, when incorporated in a steering angle variable type steering device, it is possible to prevent the driver operating the steering wheel from feeling uncomfortable. .

If the configuration of the present reference example as described above is applied to the configuration of the example of the above-described embodiment, the sliding member 43 and the first rolling bearing 36a can be used for further axial component force and moment. Rigidity can be secured.
Other configurations and operations are the same as those in the above-described example of the embodiment, and thus a duplicate description is omitted.

[Second Example of Reference Example of the Present Invention]
5-6 has shown the 2nd example of the reference example regarding this invention. In the case of the present reference example, the thickness removing portion is provided on the eccentric plate 2a and the input shaft 1a. That is, a plurality of through holes 46 and 46 are formed in the eccentric plate 2a so as to pass through both axial side surfaces of the eccentric plate 2a from the guide grooves 26a and 30a on the eccentric plate input side and output side in the radial direction. The above-mentioned thinning portion is configured by providing the same portion in the circumferential direction at equal intervals. Further, by providing a concave groove 47 such as a key groove on the outer peripheral surface of the eccentric shaft 37 provided at the intermediate portion of the input shaft 1a in a state of being recessed radially inward from the outer peripheral surface, Is configured. In the case of this reference example, the eccentric plate 2a and the input shaft 1a can be reduced in weight, and the counterweight attached to the eccentric plate 2a {the centrifugal force applied to the eccentric plate 2a is spread over the circumferential direction. The weight for making the eccentric plate 2a uniform and stabilizing the rotation (revolution and rotation) of the eccentric plate 2a can be reduced, and the centrifugal force applied to the entire eccentric plate 2a can be reduced.

  That is, the greater the weight of the eccentric plate 2a, the greater the weight of the counterweight, and the greater the centrifugal force applied to the entire eccentric plate 2a. When the centrifugal force increases in this way, the rigidity of the first and second rolling bearings 36 and 38 for supporting the eccentric plate 2a has to be ensured, and vibration caused by the rotation. May be likely to increase. On the other hand, when the through-holes 46 and 46 or the concave grooves 47 as the thinned portions are provided as in this reference example, the eccentric plate 2a, the input shaft 1a, and the counterweight are reduced in weight and centrifuged. The force can be reduced, and accordingly, the rigidity of the first and second rolling bearings 36 and 38 can be easily secured, and the vibration caused by the rotation can be reduced. Moreover. The ball speed reducer 33a as a whole can be configured to be lightweight. In addition, since the rigidity of each of the first and second rolling bearings 36 and 38 is easily secured, a biased axial force applied to the eccentric plate 2a during torque transmission (a non-uniform axial in the circumferential direction of the eccentric plate 2a) Load), and therefore, the eccentric plate 2a and the input shaft 1a can be smoothly rotated (stable rotation) regardless of the moment (moment about the radial direction) based on this axial component force. As a result, smooth torque transmission can be performed while suppressing vibration associated with torque transmission, and for example, when incorporated in a steering angle variable type steering device, it is possible to prevent the driver operating the steering wheel from feeling uncomfortable. .

The configuration of the present reference example as described above can also be applied to the configuration of the example of the above-described embodiment and the configuration of the first example of the reference example.
Other configurations and operations are the same as those of the above-described example of the embodiment and the first example of the reference example.

[Third example of reference example of the present invention]
FIG. 7 shows a third example of the reference example relating to the present invention. This reference example relates to the cage 48 incorporated in the ball speed reducer 33a (first and second ball speed change mechanisms 15a and 16a). The first and second ball speed change mechanisms 15a and 16a constituting the ball speed reducer 33a of each example described above are for restricting the radial position and the circumferential position of the input and output balls 27a and 31a. The cage is not provided. However, if necessary, the respective balls 27a, 31a are held in the respective pockets 49, 49 by the retainer 48 shown in FIG. 7, and the radial position and the circumferential position of each of the balls 27a, 31a are determined. It can also be regulated. In FIG. 7, the pair of guide grooves 34, 26a, 29a, 30a constituting the ball speed reducer 33a are indicated by solid lines and broken lines in the overlapping portion between the guide grooves 34, 26a, 29a, 30a. The portions that move along the guide grooves 34, 26a, 29a, and 30a at the centers of the balls 27a and 31a are indicated by black dots, respectively.
Other configurations and operations are the same as those of the above-described example of the embodiment and the first and second examples of the reference example, and thus overlapping illustrations and descriptions are omitted.

[Fourth example of a reference example related to the present invention]
FIG. 8 shows a fourth example of the reference example related to the present invention. This reference example also relates to the cages 50 and 51 incorporated in the ball speed reducer 33a (first and second ball transmission mechanisms 15a and 16a). In the case of this reference example, the inner diameter side cage 50 is arranged inside each of the balls 27a and 31a, and the outer diameter side cage 51 is arranged around the ball 27a and 31a. Both of these cages 50 and 51 have an annular shape, and are arranged on the inside or outside of each of the balls 27a and 31a with almost no gap. Further, in the case of the present reference example, the clearance existing between the rolling surfaces of the balls 27a and 31a adjacent in the circumferential direction is zero or very small {for example, the balls 27a and 31a are moved in the circumferential direction. In the state of being arranged at equal intervals (appropriate positions), it is suppressed to about 5 to 20 μm, or a minute value of about 0.1 to 0.5% of the diameter of each of the balls 27a and 31a. In the case of this reference example as described above, the operation of the balls 27a and 31a can be made appropriate by further ensuring the load capacity and more smoothly.
Other configurations and operations are the same as those of the third example of the reference example described above, and thus overlapping illustrations and descriptions are omitted.

[Fifth Example of Reference Example Related to the Present Invention]
9 to 10 show a fifth example of the reference example relating to the present invention. This reference example also relates to the cages 50 and 51a incorporated in the ball speed reducer 33a (first and second ball transmission mechanisms 15a and 16a). In the case of this reference example, the cross-sectional shape (in the virtual plane orthogonal to the central axis) of the inner peripheral surface of the outer diameter side retainer 51a is a waveform. That is, on the inner peripheral surface of the outer diameter side retainer 51a, the concave portions 52, 52 each having a partial arc shape smaller than the semicircular arc are rotatably held on the inner diameter side of the outer diameter side retainer 51a. It is formed with the same pitch as the appropriate pitch of the power balls 27a and 31a. The diameter of the inscribed circle of the outer diameter side cage 51a is larger than the diameter (PCD) of the pitch circle P of the balls 27a, 31a. That is, the radially inner end of the outer diameter side cage 51a does not protrude radially inward from the pitch circle P. On the other hand, as for the inner diameter side cage 50, the same one as in the case of the fourth example of the reference example described above is incorporated.
Other configurations and operations are the same as those of the fourth example of the reference example described above, and thus overlapping illustrations and descriptions are omitted.

[Sixth Reference Example for the Present Invention]
FIG. 11 shows a sixth example of the reference example relating to the present invention. This reference example also relates to the cages 50a and 51 incorporated in the ball speed reducer 33a (first and second ball transmission mechanisms 15a and 16a). In the case of the present reference example, the cross-sectional shape (in a virtual plane orthogonal to the central axis) of the outer peripheral surface of the inner diameter side cage 50a is a waveform. That is, on the outer peripheral surface of the inner diameter side retainer 50a, the partial arc-shaped recesses 52a and 52a, each smaller than a semicircular arc, are provided on the inner diameter side of the inner diameter side retainer 50a. , 31a is formed at the same pitch as the appropriate pitch. The diameter of the circumscribed circle of the inner diameter side cage 50a is smaller than the diameter (PCD) of the pitch circle P of the balls 27a and 31a. That is, the radially outer end portion of the inner diameter side cage 50a does not protrude outward in the radial direction from the pitch circle P. On the other hand, regarding the outer diameter side retainer 51, the same one as in the case of the fourth example of the reference example described above is incorporated.
Other configurations and operations are the same as those of the fourth example of the reference example described above, and thus overlapping illustrations and descriptions are omitted.

[Seventh example of a reference example related to the present invention]
FIG. 12 shows a seventh example of the reference example relating to the present invention. In this reference example, the cages 48, 50, 50a, 51, 51a as shown in the fourth to sixth examples of the reference example described above are not provided. In the case of this reference example, in order to regulate the position of each ball 27a, 31a with respect to the circumferential direction of the pitch circle P of each guide groove 34, 26a, 29a, 30a, these respective balls adjacent in the circumferential direction. The rolling surfaces of 27a and 31a are of a total ball type in which the rolling surfaces are in contact with or in close proximity to each other. According to such a structure, the circumferential positions of the balls 27a and 31a can be made appropriate while securing the load capacity of the ball reducer.
Other configurations and operations are the same as those of the fourth example of the reference example described above, and thus overlapping illustrations and descriptions are omitted.

  In addition, the configuration of one example of the above-described embodiment, the configurations of the first to seventh examples of the reference example, and the configuration of the prior invention may be used independently or a part of each configuration. Or they can be used in combination with each other. In this way, when a part or all of each configuration is used in combination with each other, depending on the performance required for the ball speed reducer or the steering angle variable type steering device incorporating the ball speed reducer, each configuration Select.

Sectional drawing which shows one example of embodiment of this invention. Sectional drawing similar to FIG. 1 which shows the 1st example of the reference example regarding this invention. The schematic diagram for demonstrating the positional relationship of the contact part of a ball | bowl and a guide groove, and the pitch circle diameter (PCD) of a rolling bearing. The diagram which shows one example of the relationship between the ratio of the pitch circle diameter (PCD) of a rolling bearing with respect to the maximum contact diameter, and the reaction force (torsion torque) of a ball reducer. Sectional drawing similar to FIG. 1 which shows the 2nd example of the reference example regarding this invention. The figure which abbreviate | omits and shows the ball and corresponds to the AA cross section of FIG. Sectional drawing which took out only the holder | retainer and took the 3rd example of the reference example regarding this invention from the same direction as FIG. Sectional drawing similar to FIG. 7 showing the fourth example. Sectional drawing similar to FIG. 7 showing the fifth example. The figure which took out the outer diameter side holder | retainer and was seen from the same direction as FIG. Sectional drawing similar to FIG. 7 which shows the 6th example of the reference example regarding this invention. The figure which took out only the ball | bowl which showed the 7th example, and was seen from the same direction as FIG. Sectional drawing which shows an example of the ball speed reducer conventionally known. Similarly disassembled perspective view. The schematic diagram for demonstrating the shape of a pair of guide groove similarly. Sectional drawing of the steering angle variable type steering device incorporating the ball reducer based on a prior invention. The B section enlarged view of FIG. (A) shows the relationship between the input shaft side guide groove, the eccentric plate side first guide groove and the plurality of input side balls constituting the first ball transmission mechanism, and (b) shows the second ball transmission mechanism. The schematic diagram which shows the relationship between the output-shaft side guide groove, eccentric plate side 2nd guide groove, and several output side ball | bowl which comprise, respectively in the state seen from the up-down direction of FIGS. The C section enlarged view of FIG. 17 which shows the cross-sectional shape of each guide groove.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Input shaft 2, 2a Eccentric plate 3, 3a Casing 4 Fixing plate 5a, 5b Guide groove 6, 6a Ball 7 Rotation extraction plate 8a, 8b Annular groove 9, 9a Output shaft 10 Input shaft 11 Output shaft 12 Intermediate Rotating cylinder 13 Electric motor 14 Eccentric plate 15, 15a First ball speed change mechanism 16, 16a Second ball speed change mechanism 17 Steering column 18 Steering wheel 19 Housing 20 Small diameter portion 21 Steering angle sensor 22 Control rotation angle sensor 23 Large diameter portion 24 Drive ring 25 Input shaft side guide groove 26, 26a Eccentric plate input side guide groove 27, 27a Input side ball 28, 28a Hump 29, 29a Output shaft side guide groove 30, 30a Eccentric plate output side guide groove 31, 31a Output side Ball 32 Nut 33, 33a Ball reducer 34 Stationary side plan Inner groove 35, 35a Lid 36, 36a First rolling bearing 37 Eccentric shaft 38 Second rolling bearing 39 Third rolling bearing 40 Cylindrical portion 41 Bottom portion 42 Through hole 43 Sliding member 44 Bolt 45 Coupling bolt 46 Through hole 47 Concave groove 48 Cage 49 Pocket 50, 50a Inner diameter side cage 51, 51a Outer diameter side cage 52, 52a Recess

Claims (5)

Cycloid wave shape or trochoid formed on at least one pair of rotation transmission members that are eccentrically arranged in parallel with each other and relatively rotated, and at least one pair of axially facing side surfaces of each of these rotation transmission members. In a ball speed reducer comprising a wave guide groove and a plurality of balls sandwiched between the guide grooves,
One rotation transmission member of the pair of rotation transmission members is supported by both rotation transmission members that slide in contact with the other rotation transmission member and a sliding member that is less rigid than the balls. And ball reducer. A disk-shaped intermediate rotation transmission member in which guide grooves are formed on both side surfaces in the axial direction;
The first rotation transmission member side guide groove formed on the end surface of the first rotation transmission member facing the one side surface in the axial direction of the intermediate rotation transmission member, and the first rotation on the one side surface in the axial direction of the intermediate rotation transmission member. The intermediate rotation transmission member side first guide groove formed in a state of facing the transmission member side guide groove, and the intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove are sandwiched between A first speed reduction mechanism comprising a plurality of first balls;
The second rotation transmission member side guide groove formed on the end surface of the second rotation transmission member facing the other side surface in the axial direction of the intermediate rotation transmission member, and the second rotation on the other side surface in the axial direction of the intermediate rotation transmission member. The intermediate rotation transmission member side second guide groove formed in a state of facing the transmission member side guide groove, and the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove A second reduction mechanism comprising a plurality of second balls,
The sliding member supported by the intermediate rotation transmission member is brought into sliding contact with at least one of the first and second rotation transmission members.
The ball reducer according to claim 1. The first rotation transmission member rotates together with the first rotation shaft, and the intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove are cycloid waves along a pitch circle having the same diameter. The shape or trochoidal wave shape, and are eccentric from each other by the amount of eccentricity between the center axis of the intermediate rotation transmission member and the center axis of the first rotation axis,
The second rotation transmission member rotates with the second rotation shaft, and the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove have a cycloid wave along a pitch circle having the same diameter. And a shape or a trochoidal wave shape, and are eccentric from each other by the amount of eccentricity between the center axis of the intermediate rotation transmission member and the center axis of the second rotation axis,
The wave number of the intermediate rotation transmission member side first guide groove and the wave number of the intermediate rotation transmission member side second guide groove are different from each other,
The ball reducer according to claim 2. The intermediate rotation transmission member swings with the rotation of the intermediate rotation shaft, and the intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove have a pitch circle having the same diameter. And a cycloid wave shape or a trochoidal wave shape along the center rotation of the intermediate rotation transmission member and the center rotation axis of the intermediate rotation shaft are offset from each other by the amount of eccentricity,
The second rotation transmission member rotates with the second rotation shaft, and the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove have a cycloid wave along a pitch circle having the same diameter. And a shape or a trochoidal wave shape, and are eccentric from each other by the amount of eccentricity between the center axis of the intermediate rotation transmission member and the center axis of the second rotation axis,
The wave number of the intermediate rotation transmission member side first guide groove and the wave number of the intermediate rotation transmission member side second guide groove are different from each other,
The ball speed reducer according to any one of claims 2 to 3. One of the intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove is a hypocycloid shape or hypotrochoid shape having a wave number of N, and the other guide groove is also An epicycloid shape or an epitrochoid shape having a wave number of “N-2”, and an axis of the intermediate rotation transmission member between the intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove "N-1" balls are arranged in a portion where the intermediate rotation transmission member side first guide groove and the first rotation transmission member side guide groove overlap with respect to the direction,
One guide groove of the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove is a hypocycloid shape or hypotrochoid shape having a wave number of M, and the other guide groove is also It is an epicycloid shape or epitrochoid shape having a wave number of “M-2”, and the intermediate rotation transmission member is interposed between the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove. "M-1" balls are disposed in a portion where the intermediate rotation transmission member side second guide groove and the second rotation transmission member side guide groove overlap in the axial direction.
The ball reducer according to any one of claims 2 to 4.

Images