JP6608674B2 - Roller gear cam mechanism - Google Patents

Description

  The present invention relates to a roller gear cam mechanism that has no backlash, has high rigidity and high transmission efficiency, and is capable of high-speed rotation.

  The roller gear cam mechanism is represented by a cam having a screw-shaped cam rib, represented by a drum cam (concave globoidal cam, roller gear cam) as one axis, and in the outer circumferential direction of the rotating member as the other axis arranged orthogonally to it. This is a mechanism for transmitting power by using one of a shaft of a cam and a rotating member as an input shaft by meshing with a plurality of bearings arranged along the shaft. The cam rib has a tapered shape, and by manipulating the distance between the input shaft and the output shaft, a preload due to the wedge effect is generated at the contact portion between the bearing and the cam rib, and backlash between the input and output can be eliminated. Further, since the torque of the input shaft is transmitted to the output shaft by the rolling contact of the bearing, the torque can be smoothly rotated without backlash, and highly efficient torque transmission with reduced friction loss at the contact portion is performed.

  Patent Document 1 discloses a roller gear type reduction device that includes a worm corresponding to a cam and a roller gear corresponding to a rotating member. The worm has two ribs, and one rib has relief processing on both side surfaces thereof, and roller followers corresponding to two bearings adjacent to each other of the roller gear come into contact with both side surfaces of the other rib. Although sandwiched from both sides, one rib is not in contact, and the rib thickness is the same at any position of the worm.

JP 2000-158293 A

  In the conventional roller gear cam mechanism, the bearing is operated by controlling the distance between the input shaft and the output shaft to preload the contact portion between the bearing and the cam rib. And thereby the bearing reverses the direction of rotation relative to the rotating member. For this reason, in the conventional roller gear cam mechanism, a section in which the bearing and the cam rib are not in contact with each other is provided near the center of the cam, and after stopping the inertial rotation of the bearing, the cam rib surface on which the bearing is in rolling contact is changed from one to the other. Therefore, it is necessary to reverse the rotation direction of the bearing with respect to the rotating member. However, when the cam is rotated at high speed, the bearing located near the center of the cam is not in contact with the cam rib, but there is a possibility that the inertial rotation of the bearing may not be settled while passing through the non-contact section between the bearing and the rib. . Then, when the bearing with inertial rotation comes into contact with the cam rib again, the cam rib gives a driving force in the opposite direction to the inertial rotation direction of the bearing, so sliding friction occurs and wears on the contact surface of the bearing and cam rib. Damage such as scuffing may be caused, and this becomes more noticeable as the cam rotates at a higher speed. Therefore, such a roller gear cam mechanism has a problem that high-speed rotation is inhibited by the cam.

  In the roller gear type reduction gear of Patent Document 1, in the worm corresponding to the cam, the thickness of each rib is the same at any position of the worm, so that the roller follower corresponding to the bearing enters the worm. When coming, there is a problem that the roller follower collides with the end of the rib and causes wear or damage to the contact surface of the roller follower or the rib. Also, when the roller follower enters the worm, the rib must always come into contact with the roller follower at any rotational angle position of the worm so that the roller follower and the rib can smoothly contact each other. Cannot be started, and sliding friction occurs while the roller follower and the rib are in contact with each other, causing wear and damage to the contact surface of the roller follower and the rib.

  Accordingly, an object of the present invention is to provide a roller gear cam mechanism that solves the above-described problems, has no backlash, has high rigidity and high transmission, and enables high-speed rotation.

  According to the present invention, the object is a cam having a screw-shaped cam rib and rotatable about a cam axis, and a rotating member rotatable about a rotating member axis perpendicular to the cam axis, the rotating member A roller gear cam mechanism comprising a rotating member capable of rolling contact with each cam rib, the two bearings adjacent to each other among the plurality of bearings. When the first bearing pair made of the rolling contact with the cam rib so as to sandwich the cam rib and the cam rotates in one direction around the cam axis, the input torque of the cam is transmitted to the rotating member, or the rotating member In the case where the input torque of the rotating member is transmitted to the cam by rotating in one direction about the rotating member axis, the first bearing pair is a cam rib. While in rolling contact, this is achieved by a roller gear cam mechanism that is in rolling contact with the cam rib such that each bearing of the first bearing pair rotates in one opposite direction with respect to the rotating member. .

  In addition, another one of the above objects is that the cam rib has a first end portion, a central portion, and a second end portion, and the thickness of the cam rib is from the first end portion toward the central portion. This is achieved by the roller gear cam mechanism, which increases to

  Another of the above objects is achieved by a roller gear cam mechanism in which the thickness of the cam rib increases from the second end portion to a certain range toward the center portion.

  Another of the above objects is achieved by a roller gear cam mechanism in which a second bearing pair comprising two adjacent bearings among a plurality of bearings is in rolling contact with the cam rib so as to sandwich the cam rib. .

  Further, another one of the above objects is that the cam has a protrusion in a cam groove provided between the cam ribs that does not contact a plurality of bearings when the cam rotates around the cam axis. This is achieved by a roller gear cam mechanism.

  Another object is achieved by a roller gear cam mechanism in which a groove is provided in the protrusion.

  Another object is achieved by a roller gear cam mechanism in which each of the plurality of bearings is a roller follower or a cam follower.

  Another of the above objects is achieved by a roller gear cam mechanism in which each of the plurality of bearings is a rolling contact bearing or a sliding contact bearing.

  As in the present invention, when the bearing pair rolls and comes into contact with the cam rib so as to sandwich the cam rib, a section in which the bearing and the cam rib are not in contact with each other is provided near the center of the cam as in the conventional roller gear cam mechanism. Since it is not necessary to stop the rotation once, there is an effect that a roller gear cam mechanism capable of high-speed rotation can be realized without causing wear or damage to the contact surfaces of the bearing and the cam rib with each other due to a conventional cause. .

  Further, as in the present invention, the gap between the bearing and the cam rib is gradually narrowed with the rotation of the cam by increasing the thickness of the cam rib to a certain range from the end to the center. Thus, the rolling contact between the bearing and the cam rib can be started smoothly, so that wear and damage of the contact surface between the bearing and the cam rib against each other can be suppressed, and smooth rotation can be obtained. As in the present invention, when the two bearing pairs are in rolling contact with the cam rib so as to sandwich the cam rib, any one of the bearing pairs always sandwiches the cam rib, and the cam rotation angle position or the rotation angle position of the rotation member. Regardless of whether there is no backlash.

  Other objects, features and advantages of the present invention will become apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is the schematic seen from the front of the roller gear cam mechanism of this invention. It is the schematic seen from the side of the roller gear cam mechanism of this invention. It is the expansion schematic seen from the front showing the contact state of the cam rib and bearing in the roller gear cam mechanism of this invention. It is the expansion schematic seen from the upper surface showing the contact state of the cam rib and bearing in the roller gear cam mechanism of this invention. It is an expanded view showing the contact state of the cam rib and bearing in the roller gear cam mechanism of this invention. It is the schematic seen from the front of another roller gear cam mechanism of the present invention. It is a partial perspective view of another roller gear cam mechanism of the present invention. It is the expansion schematic seen from the front showing the contact state of the cam rib and bearing in another roller gear cam mechanism of this invention. It is the schematic seen from the front of another roller gear cam mechanism of this invention. It is the schematic seen from the side surface of another roller gear cam mechanism of this invention. It is the schematic seen from the front at the time of making the cam of the roller gear cam mechanism of this invention into a cylindrical cam (cylindrical cam, barrel cam). It is the schematic seen from the front at the time of making the cam of the roller gear cam mechanism of this invention into the drum cam (globoidal cam).

  Examples of the present invention will be described below with reference to the drawings, but the present invention is not limited to these examples.

  With reference to FIGS. 1-12, the Example of the roller gear cam mechanism of this invention is described. 1 and 2 are a schematic view seen from the front and a side view seen from the side of the roller gear cam mechanism 101, respectively. The roller gear cam mechanism 101 includes a cam 102 having a screw-shaped cam rib 104 and rotatable about a cam axis 103, and a rotating member 107 rotatable about a rotating member axis 108 orthogonal to the cam axis 103. Each of the plurality of bearings 109 (109a, 109b,...) Arranged along the outer peripheral direction of the member 107 includes a rotating member 107 that can make rolling contact with the cam rib 104. One of the cam axis 103 and the rotating member axis 108 may be an input shaft and the other may be an output shaft, and the relationship may be reversed. Each of the plurality of bearings 109 includes a shaft member, an outer ring portion that can rotate along the outer peripheral surface of the shaft member, and the like. Arranged. By making rolling contact between each of the plurality of bearings 109 and the cam rib 104, the transmission efficiency of torque input from the cam 102 or the rotating member 107 to the output shaft side can be improved, and the roller gear cam mechanism 101 can be improved. The lifetime can be extended. Further, since each of the plurality of bearings 109 and the cam rib 104 are in line contact, the rigidity is high with respect to the external force in the rotation direction of the rotation member 107.

  Two adjacent bearings 109 a and 109 b of the plurality of bearings 109 or a pair of bearings including two adjacent bearings 109 c and 109 d are in contact with the cam rib 104 so as to sandwich the cam rib 104. That is, the first bearing pair including the first bearing 109a and the second bearing 109b contacts the portion 104a so as to sandwich the portion 104a of the series of cam ribs 104, or the third bearing 109c, A second bearing pair including the fourth bearing 109d is in contact with the portion 104b so as to sandwich the portion 104b of the series of cam ribs 104. When the cam 102 is on the input side, the cam 102 is rotated in one direction as indicated by an arrow about the cam axis 103, whereby the input torque of the cam 102 is transmitted to the rotating member 107, and the rotating member axis 108 is The rotation member 107 rotates as indicated by an arrow as the center. When the rotary member 107 is on the input side, the input torque of the rotary member 107 is transmitted to the cam 102 by rotating in one direction as indicated by an arrow about the rotary member axis 108, and the cam axis 103 is The cam 102 rotates as shown by an arrow. In these cases, while the first bearing pair consisting of the first bearing 109a and the second bearing 109b is in contact with the cam rib 104, the first bearing 109a and the second bearing 109b are indicated by arrows. In this manner, the rotating members 107 rotate in opposite directions and come into rolling contact with the cam ribs 104. Further, while the second bearing pair including the third bearing 109c and the fourth bearing 109d is in contact with the cam rib 104, the third bearing 109c and the third bearing 109d are as shown by arrows. The rotating members 107 rotate in opposite directions and are in rolling contact with the cam ribs 104.

  This will be described in more detail with reference to FIGS. FIG. 3 is an enlarged schematic view showing the contact state between the bearings 109a to 109e arranged along the outer peripheral direction of the cam rib 104 and the rotating member 107 at one timing of the roller gear cam mechanism 101. The enlarged schematic view seen from the upper surface showing the contact state of the cam rib 104 and each bearing 109a-109e in the same timing as FIG. 3 of the roller gear cam mechanism 101 is shown. A first bearing pair including a first bearing 109a and a second bearing 109b adjacent to each other among the plurality of bearings 109 sandwiches a first cam rib 104a which is a part of a series of cam ribs 104, and the first The bearing 109a and the second bearing 109b are in contact with the first cam rib surface 105 and the second cam rib surface 106 of the first cam rib 104a, respectively. The second bearing pair including the third bearing 109c and the fourth bearing 109d adjacent to each other among the plurality of bearings 109 sandwiches the second cam rib 104b, which is a part of the series of cam ribs 104, and The third bearing 109c and the fourth bearing 109d are in contact with the first cam rib surface 105 and the second cam rib surface 106 of the second cam rib 104b, respectively. When the cam 102 rotates around the cam axis 103 in one direction as indicated by an arrow, the first bearing pair is a series of the first cam rib 104a, the second cam rib 104b, and the third cam rib 104c. While in contact with the cam rib 104, the first bearing 109a and the second bearing 109b rotate in opposite directions with respect to the rotating member 107 (in FIG. 4, the first bearing 109a is a watch). The second bearing 109b rotates counterclockwise, and is in rolling contact with the cam rib 104. Further, while the second bearing pair is in contact with the series of cam ribs 104 including the first cam rib 104a, the second cam rib 104b, and the third cam rib 104c, the third bearing 109c and the fourth bearing are also provided. 109 d rotates in the opposite direction with respect to the rotating member 107 (in FIG. 4, the third bearing 109 c rotates clockwise and the fourth bearing 109 d rotates counterclockwise), while the cam rib 104 is rotated. In contact with rolling.

  When the cam 102 rotates about the cam axis 103 in the direction opposite to the arrow, while the first bearing pair is in contact with the cam rib 104, the first bearing 109a and the second bearing 109b rotate in the opposite direction with respect to the rotating member 107 (in this case, the first bearing 109a rotates counterclockwise, the second bearing 109b rotates clockwise, and in the opposite direction to FIG. 4). Is in rolling contact with the cam rib 104. In addition, while the second bearing pair is in contact with the cam rib 104, the third bearing 109c and the fourth bearing 109d rotate in opposite directions with respect to the rotating member 107 (in this case, the first bearing 109). The third bearing 109c rotates counterclockwise and the fourth bearing 109d rotates clockwise, and rotates in the direction opposite to that in FIG. 4), and is in rolling contact with the cam rib 104.

  The contact state between the cam rib 104 and the plurality of bearings 109 is the same both when the cam 102 rotates the rotating member 107 as the input side and when the rotating member 107 rotates the cam 102 as the input side. It becomes the state of.

  Thus, when the cam 102 rotates in one direction, it is not necessary to stop the rotation of the bearings 109a to 109d with respect to the rotating member 107 while the bearings 109a to 109d are in contact with the cam rib 104. Since the bearings 109a to 109d rotate only in one direction with respect to the rotating member 107, the bearings 109a to 109d and the cam rib 104 do not cause wear or damage to contact surfaces with each other, and high speed rotation is possible. Possible roller gear cam mechanism can be realized. Further, since the first bearing pair or the second bearing pair is in contact with the cam rib 104 so as to sandwich the cam rib 104, the roller gear cam mechanism 101 without backlash can be realized. The bearing 109e that is no longer in contact with the cam rib 104 may or may not rotate with respect to the rotating member 107 due to inertia.

  Further, FIG. 5 shows the roller gear cam mechanism 101 developed from the top surface showing the contact state between the bearings 109a to 109e and the series of cam ribs 104 including the first cam rib 104a, the second cam rib 104b, and the third cam rib 104c. The figure is shown. The horizontal axis represents the position of the cam 102 in the direction of the cam axis 103, and the vertical axis represents the rotation angle of the cam 102. As shown in FIG. 5, the cam rib 104 has a first end (point A), a center (points B to E), and a second end (point F), and the cam rib 104 has a thickness of You may increase as it goes to a center part (B point-E point) from a 1st edge part (A point). The first bearing 109 a and the second bearing 109 b of the first bearing pair that have entered the cam rib 104 due to the rotation of the rotating member 107 accompanying the rotation of the cam 102 or the rotation of the rotating member 107 itself are There is no contact at the first end (point A) (non-contact zone bearing). This is because the thickness of the cam rib 104 at the first end (point A) is smaller than the thickness of the cam rib 104 at the center (points B to E). As the cam 102 further rotates, the thickness of the cam rib 104 gradually increases from the point A to the point B. Therefore, the gap between the first bearing 109a and the first cam rib surface 105, and the second The gap between the bearing 109b and the second cam rib surface 106 is gradually reduced (gap reduction section bearing). When the cam 102 further rotates and the first bearing pair reaches the point B, the gap between the first bearing 109a and the first cam rib surface 105, and the second bearing 109b and the second cam rib surface 106 are increased. The gap disappears and a so-called negative gap state is established (complete negative gap position bearing). From point B to point E, the first bearing pair (109a, 109b) or the second bearing pair (109c, 109d) rolls into contact with the cam rib 104 so as to sandwich the cam rib 104 (contact zone bearing). . As described above, by providing the gap decreasing section from the point A to the point B that gradually reduces the gap between the bearing 109 and the cam rib 104, the rolling contact between the bearing 109 and the cam rib 104 can be started smoothly. The wear and damage of the contact surfaces of the bearing 109 and the cam rib 104 with respect to each other can be suppressed. The clearance reduction section and the negative clearance amount between the bearing 109 and the cam rib 104 are determined so that the bearing 109 can shift to the rotation state within the minimum cam rotation angle range while suppressing sliding friction as much as possible. The

  Furthermore, as shown in FIG. 5, the thickness of the cam rib 104 may increase from the second end (point F) toward the center (points B to E). In this way, by providing a clearance decreasing section that gradually decreases the clearance between the bearing 109 and the cam rib 104 not only at the points A to B but also at the points F to E, the cam 102 or the rotating member 107 Even in the case of rotating in any direction and transmitting torque to each other, the rolling contact between the bearing 109 and the cam rib 104 can be started smoothly, and the contact surface between the bearing 109 and the cam rib 104 with respect to each other can be worn or damaged. It can be suppressed. When the cam 102 rotates only in one direction, the bearing 109 and the bearing 109 are arranged at the end of either the point A to the point B or the point F to the point E according to the rotation. You may provide the clearance reduction area which makes the clearance gap with the cam rib 104 small gradually.

  The first bearing pair (109a, 109b) and the second bearing pair (109c, 109d) may be in contact with the cam rib 104 so as to sandwich the cam rib 104. That is, as shown in FIG. 5, at the rotation angle of the cam 102, the first bearing pair (109a, 109b) moves from the point B to the point C to the first cam rib surface 105 and the second cam rib surface 106 from the cam rib 104. The two bearing pairs are in contact with each other, and the second bearing pair (109c, 109d) is in contact with the first cam rib surface 105 and the second cam rib surface 106 of the cam rib 104 from the point D to the point F, respectively. An overlap section in which the cam rib 104 is sandwiched may be provided. By providing the overlap section in this manner, the first bearing pair (109a, 109b) is inserted into the cam rib 104 before the second bearing pair (109c, 109d) is inserted into the cam rib 104. Since one bearing pair always sandwiches the cam rib 104, the roller gear cam mechanism 101 without backlash due to the rotational angle positions of the cam 102 and the rotating member 107 can be realized.

  FIG. 6 shows a schematic view of another roller gear cam mechanism 101 as viewed from the front. As shown in FIG. 6, the cam 102 is brought into contact with a plurality of bearings 109 when the cam 102 rotates about the cam axis 103 in a cam groove 110 provided between the screw-shaped cam ribs 104. Alternatively, the protrusion 111 may be provided at a position where the cam rib 104 and each of the plurality of bearings 109 do not interfere with each other. Since the cam 102 has the protrusion 111 in this way, in the roller gear cam mechanism 101, the rotation balance can be improved as a balance weight.

  FIGS. 7 and 8 show a partial perspective view of still another roller gear cam mechanism and an enlarged schematic view seen from the front showing the contact state between the cam rib and the bearing. As shown in FIGS. 7 and 8, lubricating oil is applied to each of the plurality of bearings 109 on the protrusions 111 of the cam groove 110 disposed at positions where the cam rib 104 and each of the plurality of bearings 109 do not interfere with each other. A shape such as a groove 112 may be provided for the purpose of supplying and holding.

  9 and 10 are a schematic view of the roller gear cam mechanism 101 as viewed from the front and a schematic view as viewed from the side, respectively. The difference between the roller gear cam mechanism 101 shown in FIGS. 7 and 8 and the roller gear cam mechanism 101 shown in FIGS. 1 and 2 is that the screw-shaped winding direction of the cam rib 104 is reversed. By reversing the screw-shaped winding direction in this way, even if the cam 102 of FIGS. 1, 2, 7 and 8 is rotating in the direction of the same arrow about the cam axis 103, it can rotate. The member 107 can be rotated in opposite directions around the rotation member axis 108 (the rotation member 107 is rotated counterclockwise in FIG. 1 and clockwise in FIG. 7).

  Each of the plurality of bearings 109 may be a roller follower or a cam follower.

  Each of the plurality of bearings 109 includes a shaft member, an outer ring portion that can rotate along the outer peripheral surface of the shaft member, and the like, and is a rolling contact bearing that includes a roller or the like between the shaft member and the outer ring portion. Alternatively, it may be a sliding contact bearing that does not include rollers or the like. In addition, if the shape of the groove 112 or the like is provided on the protrusion 111 arranged at a position where the cam rib 104 and each of the plurality of bearings 109 do not interfere with each other in the cam groove 110, the groove 112 from which the lubricating oil is retained is removed. Lubricating oil is supplied to each of the plurality of bearings 109, so that friction between the outer ring portion and the cam rib 104 can be further suppressed.

  The cam 102 is not limited to the drum cam as shown in FIGS. 1 to 10, and for example, a cylindrical cam (barrel cam) 113 shown in FIG. 11 or a drum cam (globoidal cam) shown in FIG. 12. Other cams having screw-shaped cam ribs such as 114 may be used. The operation is the same as that described above even for a cylindrical cam or a drum cam.

  The positional relationship between the cam 102 and the rotating member 107 may be inscribed in addition to circumscribing the rotating member 107 depending on the shape of the cams 102, 113, and 114.

  While the above description has been made with respect to particular embodiments, it will be apparent to those skilled in the art that the invention is not limited thereto and that various changes and modifications can be made within the scope of the principles of the invention and the appended claims. is there.

DESCRIPTION OF SYMBOLS 101 Roller gear cam mechanism 102 Cam 103 Cam axis 104 Cam rib 104a 1st cam rib 104b 2nd cam rib 104c 3rd cam rib 105 1st cam rib surface 106 2nd cam rib surface 107 Rotating member 108 Rotating member axis 109 Bearing 109a 1st Bearing 109b Second bearing 109c Third bearing 109d Fourth bearing 109e Fifth bearing 110 Cam groove 111 Projection 112 Groove 113 Cylindrical cam 114 Drum cam

Claims (8)

A cam having a screw-shaped cam rib and rotatable about a cam axis;
A rotating member that is rotatable about a rotating member axis that is orthogonal to the cam axis, and each of a plurality of bearings arranged along an outer peripheral direction of the rotating member can be in rolling contact with the cam rib. A roller gear cam mechanism comprising a rotating member,
A first bearing pair composed of two adjacent bearings of the plurality of bearings is in rolling contact with the cam rib so as to sandwich the cam rib;
When the cam rotates in one direction around the cam axis to transmit the input torque of the cam to the rotating member, or the rotating member rotates in one direction around the rotating member axis When the input torque of the rotating member is transmitted to the cam, each bearing of the first bearing pair is in contact with the rotating member while the first bearing pair is in rolling contact with the cam rib. Rolling contact with the cam rib so as to rotate in one opposite direction ,
The cam rib has a first end portion, a central portion, and a second end portion. In the first end portion, there is a gap between each of the first bearing pairs and the cam rib. The first bearing pair does not contact the cam rib, and the gap between each of the first bearing pair and the cam rib decreases from the first end toward the central portion. in the central part, the longer the first gap between each bearing pair and the cam rib, said first bearing pair is characterized by you rolling contact with said cam rib so as to sandwich the cam rib roller gear cam mechanism. Thickness before Symbol cam rib is a roller gear cam mechanism according to claim 1, characterized in that increases from the first end to a certain range toward the central portion.   The roller gear cam mechanism according to claim 2, wherein the thickness of the cam rib increases to a certain range from the second end toward the center.   4. The second bearing pair formed of two adjacent bearings among the plurality of bearings is in rolling contact with the cam rib so as to sandwich the cam rib. 5. The roller gear cam mechanism described in 1.   The cam has a protrusion in a cam groove provided between the cam ribs that does not contact the plurality of bearings when the cam rotates about the cam axis. 5. The roller gear cam mechanism according to any one of 1 to 4.   The roller gear cam mechanism according to claim 5, wherein a groove is provided in the protrusion.   The roller gear cam mechanism according to any one of claims 1 to 6, wherein each of the plurality of bearings is a roller follower or a cam follower.   The roller gear cam mechanism according to any one of claims 1 to 7, wherein each of the plurality of bearings is a rolling contact bearing or a sliding contact bearing.