JP4134791B2 - Double row eccentric thrust bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double row eccentric thrust bearing.
[0002]
[Prior art]
A conventional double-row eccentric thrust bearing is publicly implemented by one inner race, two outer races facing both surfaces of the inner member, and two rows of rolling elements interposed between the races. Has been. In this double row eccentric thrust bearing, two outer races are provided, and the two rows of rolling elements support axial loads in opposite directions to support axial loads in both directions. Such publicly implemented double-row eccentric thrust bearings include those in which balls as rolling elements are randomly arranged in the space between the races, or those in which balls are provided in a total ball state in the space between the races. It was.
[0003]
[Problems to be solved by the invention]
However, such a conventional double-row eccentric thrust bearing has a large resistance during operation and excessive energy loss. That is, when the rolling elements are randomly arranged as described above or arranged in a full ball state, the rolling elements come into contact with each other and rub against each other to cause friction. As a countermeasure, it is conceivable to use a cage to maintain the relative relationship between the rolling elements. In this case, friction has occurred due to sliding between the cage and the race.
[0004]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a double-row eccentric thrust bearing that is relatively movable by a certain distance and that has an extremely small loss during the relative movement.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, two annular outer members concentrically facing each other and integrally joined, and an annular inner member interposed concentrically between the two outer members, Each of the two outer members has an annular outer case portion and an annular plate-like outer race portion attached to the inner surface of the outer case portion, and the inner member is a circular shape. An annular inner case portion and an annular plate-like inner race portion extending in a radial direction from the inner case portion, and between the two outer race portions facing both surfaces of the inner race portion A rolling element guide portion that is a plurality of rolling elements in a plurality of rows sandwiched between and an annular member fixed to the inner member or the outer member, and restricts a movable range of each rolling element within a predetermined range. A double row eccentric thrust bearing comprising
The rolling element guide portion is provided with three or more circular movable range restricting holes on the same circumference and at equal positions in the circumferential direction, and one rolling element per one of the movable range restricting holes. Has been placed,
The axial center of the inner race portion coincides with the axial center of the bearing, and the bearing is configured to be symmetrical on both sides with respect to a plane passing through the axial center and perpendicular to the axis. Double row eccentric thrust bearings.
[0006]
If it does in this way, between the rolling elements separately partitioned by the rolling element guide part, the rolling elements do not contact each other. Moreover, since the rolling element guide is being fixed to the inner member or the outer member, it does not slide with these members. Therefore, there is little resistance when the rolling element moves within the range restricted by the rolling element guide part. Further, since the outer member and the inner member are annular and are arranged concentrically with each other, the gap between them is an annular with a constant width. In addition, since the moving range of each rolling element regulated by the rolling element guide is also a certain range, the bearing can be relatively moved by a certain distance .
[0007]
The rolling element guide portion regulates the movable range of each rolling element, but at the same time, it is easy to adjust and arrange each rolling element at the optimum position on the race. In other words, with the light preload applied, the bearing is relatively moved over the entire circumference, so that the rolling element with the misaligned rolling element guide is slid on the race to adjust the rolling element to the optimum position. can do.
[0008]
Moreover, the bearing which consists of the above structure can supply with the assembled bearing single-piece | unit, without each component separating. In this bearing, each rolling element can move only within a range regulated by the rolling element guide portion fixed to the inner member, and each rolling element cannot move beyond this range. Therefore, for example, the inner member and the outer member cannot rotate relative to each other by a predetermined angle or more.
[0009]
Further, since the movable range regulating hole of the rolling element guide portion is circular, it can be a bearing that can be relatively moved by a fixed distance in all radial directions.
Further, since three or more circular movable range restricting holes are provided on the same circumference and at equal positions in the circumferential direction, the rolling elements provided in the movable range restricting holes are even in the circumferential direction and the radial direction. It becomes arrangement, and the axial load and moment load of the bearing can be supported more stably.
In addition, since only one rolling element is disposed in one movable range restriction hole, the rolling elements do not contact each other and cause friction.
[0010]
Furthermore, it is preferable that the movable range of the rolling element in the radial direction is half of the relative movable range generated by the radial gap between the outer member and the inner member. In this way, when the inner member and the outer member are moved relative to each other until there is no radial gap between them, the rolling element moves to a position where there is substantially no gap between the rolling element guide portion. That is, when the inner member and the outer member are relatively moved over the entire relative movable range, the rolling elements also move over substantially the entire movable range. Therefore, there is no extra gap between the inner member and the outer member, or the extra gap can be minimized. Therefore, it is possible to increase the eccentric range while reducing the size of the bearing.
[0011]
Further, it is preferable that a radial movement distance of the rolling element regulated by the rolling element guide part is substantially equal to a radial width of the inner race part or the outer race part. The radial width of the portion or the outer race portion can be minimized. Therefore, the weight of the bearing can be reduced and the cost can be reduced.
Further, it is preferable that the inner case portion and the inner race portion are separate from each other, and the inner race portion is integrally joined while being sandwiched between the two inner case portions.
Moreover, it is preferable for weight reduction that the said inner race part and the outer race part are comprised with an iron-type metal, and the said outer case part and inner case part are comprised with a light metal.
Further, it is fixed to an axially outer end portion of the inner case portion, and extends from the axial direction outer surface of the outer case portion toward a radially outer side, and an axially outer surface of the outer case portion. It is preferable that a shield is provided so as to overlap with a slight gap. In this case, entry of foreign matter into the bearing can be suppressed, and lubricant such as lubricating oil and grease in the bearing can be prevented from leaking to the outside.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of an eccentric thrust bearing according to a first embodiment of the present invention, and FIG. 2 is a sectional view of this bearing (the lower half of the shaft is omitted from the description). As shown in FIGS. 1 and 2, the bearings 1 are opposed to each other in the axial direction and are integrally joined by outer screws 11 (see FIG. 2, omitted in FIG. 1) at the radially outer peripheral edge thereof. It has two annular outer members 2 and 2 and an annular inner member 3 interposed between the two outer members. FIG. 2 is a diagram in a neutral state (hereinafter referred to as a standard state or the like) in which the balls 8 as rolling elements are not moving in any radial direction.
[0013]
Each of the two outer members 2, 2 has an annular outer case portion 4 and an annular plate-like outer race portion 5 attached to the inner surface of the outer case portion 4. The outer case portion 4 and the outer race portion 5 are separate members, and the outer race portion 5 having an annular plate shape is attached to a recess 4 a provided on the opposite surface side of the outer case portion 4. (See FIG. 2). The two outer case portions 4 and 4 are integrally joined by an outer screw 11 in the vicinity of the radially outer peripheral edge portion (see FIG. 2, not shown in FIG. 1). The inner member 3 is fixed while being sandwiched between two annular inner case portions 6 and 6 and the two inner case portions 6 and 6 from the front and back sides by inner screws 12 (see FIG. 2, not shown in FIG. 1). An annular plate-shaped inner race portion 7 is provided. The inner case portions 6 and 6 and the inner race portion 7 are separated from each other. The inner race portion 7 is sandwiched between the two inner case portions 6 and 6 and the three members are integrally joined with the inner screw 12. (See FIG. 2; omitted in FIG. 1). As shown in FIG. 2, the axial center of the inner race portion 7 coincides with the axial center of the bearing 1, and the bearing 1 is configured symmetrically on both sides with respect to a plane passing through the center and perpendicular to the axis. It has become.
[0014]
In the bearing 1 according to the first embodiment, the inner case portion 6 is integrated with the rolling element guide portion 9. That is, the flange-shaped rolling element guide portion 9 extends radially outward from the outer peripheral surface side of the annular inner case portion 6. The annular rolling element guide portion 9 is provided with movable range restricting holes 9a that are circular through holes that restrict the movable range of the balls 8 that are the rolling elements at equal intervals in the circumferential direction. . The hole diameters and the radial positions (in the standard state) of all the movable range restriction holes 9a are the same. One ball 8 is arranged for each movable range regulating hole 9a, and each ball 8 is positioned at the center of the movable range regulating hole 9a in the standard state (see FIG. 2). In addition, since the axial clearance X is provided between the axially outer side surface of the rolling element guide portion 9 and the raceway surface of the outer race portion 5, the rolling element guide portion 9 does not move even if the bearing 1 moves relatively. There is no contact with the outer race part 5 or sliding with respect to each other.
[0015]
Both of the inner race portion 7 in the axial direction are both raceway surfaces, and a plurality of balls 8 as rolling elements are sandwiched between the two outer race portions 5 and 5 facing both the inner race portion 7. This is a double row structure thrust bearing. A total of 64 balls 8 are used in 32 rows per row, and these balls 8 are arranged substantially evenly in the circumferential direction in each row. As described above, the plurality of balls 8 serving as the support points of the bearing 1 are arranged at substantially equal intervals in the circumferential direction, so that the axial load and the moment load are stably supported, and the load applied to each ball 8 is also increased. Can be equalized.
[0016]
Thin annular plate-like shields 13 and 13 are provided on the outermost surface in the axial direction of the bearing 1. As shown in FIG. 2, these shields 13, 13 are fixed to the axially outer end portion of the inner case portion 6, and from there toward the radially outer side along the axially outer surface of the outer case portion 4. It is extended. Since the shields 13 and 13 are arranged so as to overlap with the axially outer side surface of the outer case portion 4 via a slight gap, the shielding of the foreign matter into the bearing 1 and the lubrication within the bearing 1 are suppressed. It has a sealing function to prevent lubricants such as oil and grease from leaking outside. In order to further enhance the sealing effect, a seal for sealing the inside of the bearing 1 can be further added.
[0017]
Except for the ball 8 which is a rolling element, all members of the bearing 1 have an annular shape having a constant radial width over the entire circumference, and are all concentrically arranged in a standard state. Therefore, in the standard state, a gap having a distance M in the radial direction is formed on the entire circumference in the circumferential direction between the outer circumferential surface 15 of the rolling element guide portion that is the radially outermost end surface of the inner member 3 and the outer members 2 and 2. Exist. Further, in the standard state, the radially innermost end surface 17 of the outer members 2 and 2 and the inner member 3 (in this embodiment, the radially innermost member of the outer members 2 and 2 out of the shield 13 joined to the inner case portion 6). Between the end surface 17 and the opposing surface 16), a gap having a distance L in the radial direction exists over the entire circumference in the circumferential direction. Thus, since the bearing 1 has a uniform gap over the entire circumference in the circumferential direction, it can be moved relative to the circumferential direction by a fixed distance. A relative movable range between the outer member 2 and the inner member 3 is determined by the radial gap between the outer member 2 and the inner member 3.
[0018]
On the other hand, the outer race parts 5 and 5 are annular plate-shaped members having a predetermined radial width, and the radial width is the same over the entire circumference. Thus, the outer race portions 5 and 5 have a width in the radial direction, and the inner race portion 7 has a radial width equal to or greater than the radial width of the outer race portions 5 and 5 and the outer race portions 5 and 5. Opposite. Since the diameter of each movable range regulating hole 9a of the rolling element guide portion 9 is larger than the diameter of each ball 8 accommodated in each movable range regulating hole 9a, the ball 8 can be moved around the ball 8. There is a gap to do. On the other hand, the inner and outer race portions 5 and 7 are disposed in substantially the entire range of the movable range restricting hole 9a so that the balls 8 do not disengage from the inner and outer race portions 5 and 7 even if the ball 8 moves over the entire range of the movable range restricting hole 9a. Opposite. Therefore, each ball 8 can move in the radial direction and the circumferential direction within the range regulated by the movable range regulating hole 9a. That is, in this bearing 1, the ball 8 can roll until it comes into contact with the inner peripheral surface of the movable range regulating hole 9a. In the standard state, since the ball 8 is located at the center of the movable range restricting hole 9a, a distance R between the ball 8 and the inner peripheral surface of the movable range restricting hole 9a around the entire periphery of the ball 8 is a distance R. (See FIG. 2). Therefore, the ball 8 can move by a distance R in an arbitrary direction within the operating surface.
[0019]
In this bearing 1, the distance L is twice the distance R. That is, the following formula L = 2R
Is established. This corresponds to the fact that the moving distance of the balls 8 that are rolling elements is half (1/2) the relative moving distance of the inner and outer race parts 5 and 7. The distance M is substantially the same as the distance L. Furthermore, the distance M and the distance L are preferably the same. Further, it is sufficient that L ≧ 2R.
[0020]
Thus, in the bearing 1, the relative movable range generated by the radial gap between the outer member 2 and the inner member 3 corresponds to the movable range of the ball 8 regulated by the hole diameter of the movable range regulating hole 9a. is doing. That is, when the outer member 2 and the inner member 3 are moved relative to each other until the distance L (the radial gap distance between the radially innermost end surface 17 of the outer members 2 and 2 and the inner member 3) disappears, the movement is performed. It moves until the distance R around the ball 8 disappears in the direction. That is, when the outer member 2 and the inner member 3 are relatively moved over the entire relative movable range, the ball 8 moves over the entire movable range. Therefore, there is no extra space between the radially innermost end surface 17 of the outer member 2 and the inner member 3. Therefore, the eccentricity possible range can be enlarged while downsizing the bearing 1. Furthermore, the weight reduction and cost reduction of the bearing 1 are attained.
[0021]
Further, in the bearing 1 of the first embodiment, the distance L is substantially the same as the distance M (the radial clearance distance between the outer circumferential surface 15 of the rolling element guide portion and the outer members 2 and 2). That is, the distance M is approximately twice the distance R. By doing so, since the gap distance M is minimized, the outer diameter of the outer member 2 can be reduced, and the bearing 1 can be reduced in size. In addition, when the difference between the distance L and the distance M is large, the eccentricity range of the bearing 1 is restricted by the smaller gap among them, but the bearing 1 is reduced in size by making the both substantially the same. Thus, the allowable eccentric range of the bearing 1 can be maximized.
[0022]
Further, in this bearing 1, the radial movement distance of the ball 8, which is a rolling element restricted by the rolling element guide portion 9, substantially corresponds to the radial width of the outer race portion 5. That is, as shown in FIG. 2, the radial width of the outer race portion 5 is substantially equal to the hole diameter of the movable range restricting hole 9a (more specifically, slightly smaller than the hole diameter of the movable range restricting hole 9a). . Therefore, even if the ball 8 moves in the radial direction until it comes into contact with the inner peripheral surface of the movable range regulating hole 9a, the outer race portion 5 does not come off, while the radial width of the outer race portion 5 is increased more than necessary. Not.
[0023]
Further, the radial width of the inner race portion 7 is larger than the hole diameter of the movable range restricting hole 9a, which is to secure a pinch allowance for fixing the inner race portion 7, It's not bigger than necessary. That is, as for the inner race portion 7, the inner race portion 7 is fixed by being sandwiched between the two inner case portions 6 and 6, so that the radial width is movable within the movable range in order to secure a portion for the pinching allowance. Although it is wider than the hole diameter of the restriction hole 9 a, the radial position of the outer peripheral surface of the inner race portion 7 is the same as that of the outer peripheral surface of the outer race portion 5.
[0024]
Thus, the radial width of the outer race portion 5 substantially corresponds to the radial movement distance of the ball 8 that is a rolling element, and the radial width of the inner race portion 7 is also the ball 8 excluding the pinching allowance. Therefore, the radial width of the inner and outer race portions 5 and 7 is minimized. While the inner and outer race parts 5 and 7 are made of a ferrous metal such as steel for bearings, the outer case part 4 and the inner case part 6 can be made of a light metal such as an aluminum alloy, so the inner and outer race parts 5 and 7 are made smaller. As a result, the bearing 1 can be reduced in weight and cost.
[0025]
When the bearing 1 moves within a circular range restricted by the movable range restricting hole 9 a of the rolling element guide portion 9, no sliding occurs between the inner and outer race portions 5, 7 and the rolling element guide portion 9. This is because the rolling element guide portion 9 is fixed to the inner member 3 and integrated with the inner race portion 7, and between the rolling element guide portion 9 and the outer race portion 5 by the gap X (see FIG. 2). This is because there is no contact. Therefore, the bearing 1 has a very low resistance during relative movement.
[0026]
The rolling element guide portion 9 has an annular shape, and 32 movable range restricting holes 9a provided in the rolling element guide portion 9 are provided on the same circumference and at equal positions in the circumferential direction. Since the balls 8 which are rolling elements are disposed in each of the movable range restricting holes 9a, the support points of the bearing 1 are uniform in the radial direction and the circumferential direction, and the axial load and the moment load can be supported more stably. Furthermore, since one rolling element is arranged for each of these movable range regulating holes 9a, the balls 8 do not come into contact with each other and rub against each other, and the resistance during relative movement can be further reduced. Note that the number of movable range restriction holes 9a can be increased as long as adjacent movable range restriction holes 9a do not contact each other, and the number of balls 8 can be increased to improve the load capacity of the bearing 1.
[0027]
In the present embodiment, as shown in FIG. 2, the two inner case portions 6, 6 provided on both surfaces of the inner race portion 7 have the same phase on the front and back of the inner race portion 7. The arrangement positions of the movable range restricting holes 9a and the balls 8 are also in phase on both surfaces of the inner race portion 7. The present invention is not limited to such a configuration, and the phase of the movable range restricting hole 9a and the ball 8 may be different between the front and back of the inner race portion 7.
The shields 13 and 13 are devised so as not to limit the eccentricity possible range of the bearing 1. That is, as shown in FIG. 2, the shield step provided in the outer surface of the outer case portion 4 from the radially outer ends of the shields 13 and 13 in the standard state and having substantially the same depth as the surface thickness of the shields 13 and 13. The radial distance S up to 14 is slightly longer than the distance L. In the standard state, the radial length T of the portion where the shields 13 and 13 and the outer surface of the outer case portion 4 overlap each other is slightly longer than the distance L. The inside is hidden.
[0029]
In order to arrange each ball 8 at the position shown in FIG. 2, that is, at the center position of the movable range restricting hole 9a in the standard state, the bearing 1 is placed in a state in which a light preload is applied between the inner and outer members with a preload adding screw or the like. What is necessary is just to carry out relative movement to the maximum over all the radial directions (all the circumferences). In this way, the ball 8 which is displaced from the center of the movable range restricting hole 9a in the standard state is pushed by the inner peripheral surface of the movable range restricting hole 9a and the sliding position is adjusted on the inner and outer race portions 5 and 7. The Thereafter, when the bearing 1 is used, the preload adding screw may be fastened with a specified torque. In addition, when the height (axial thickness) of the inner peripheral surface of the movable range regulating hole 9a of the rolling element guide portion 9 is equal to or larger than the radius (ball diameter / 2) of the ball 8, the ball 8 is movable range regulating hole. When pressed by the inner peripheral surface of 9a, the apex of the ball 8 comes into contact with the inner peripheral surface, and the position adjustment of the ball 8 is performed stably, which is preferable.
[0030]
As described above, the rolling element guide portion 9 not only regulates the movable range of the ball 8 but also reliably and simply arranges the ball 8 at the center position (standard state) of the movable range regulating hole 9a. It is possible to secure a gap of a certain distance R from the center position, and to play a role that allows the ball 8 to move within this range. In the bearing 1 according to the first embodiment, the ball 8 is lifted from the inner and outer races 5 and 7 by applying an eccentric load to the ball 8, and the position of the ball 8 is the movable range restriction hole in the standard state. It may be displaced from the center position of 9a. Even in this case, the position of the ball 8 can be corrected in an extremely simple manner in the assembled state of the bearing 1 by performing the maximum relative movement under the light preload as described above. Further, in order to suppress the positional deviation of the balls 8 and maintain the PCD (pitch circle diameter) of each ball 8, a preload is applied between the inner and outer members by a preloading screw or the like, and each ball 8 and the inner and outer races 5 are provided. , 7 should be kept from slipping.
[0031]
The material of the bearing 1 is not particularly limited. However, from the viewpoint of reducing the weight of the bearing 1, the outer case portion 4 and the inner case portion 6 are made of a light metal such as an aluminum alloy or resin, and the inner race portion 7 and the outer race portion 5 are made of an iron-based metal such as bearing steel. It is preferable to do this. If it does in this way, while only the inner and outer race parts 5 and 7 used as the contact with the ball 8 among the outer member 2 and the inner member 3 are made of steel having high hardness, the outer case part 4 and the inner case part The bearing 1 can be reduced in weight by using 6 as a light metal such as an aluminum alloy. Normally, the ring-shaped cage 9 is made of resin or the like, and the balls 8 are made of bearing steel or the like. The shield 13 can be made of stainless steel or resin.
[0032]
FIG. 3 is a cross-sectional view of the bearing 20 according to the second embodiment of the present invention (the description of the lower half from the shaft center is omitted). In this bearing 20, unlike the bearing 1 of the first embodiment, the outer member 2 includes outer outer members 21 and 21 in which the outer race portion 5 and a part of the outer case portion 4 are integrated, and the outer case portion 4. It consists of a ring-shaped outer case 22 which is the remaining part of. The two outer integrated members 21, 21 having a substantially annular plate shape are integrally connected by the outer screw 11 via the ring-shaped outer case 22 in the vicinity of the outermost edge in the radial direction. This is preferable in that the number of parts is reduced and the axial thickness of the bearing 20 can be easily reduced. However, when the outer race portion is made of bearing steel or the like, the entire outer integrated member 21 in which the outer race portion and a part of the outer case portion are integrated is made of bearing steel or the like. This is disadvantageous from the viewpoint of weight reduction. That is, from the viewpoint of weight reduction, it is preferable to separate the outer case portion 4 and the outer race portion 5 as in the bearing 1 according to the first embodiment.
[0033]
In the bearing 20, the rolling element guide portion is not integrated with the inner case portion 6 as in the bearing 1 of the first embodiment, and the rolling element guide portion 23 is separately provided. The rolling element guide portion 23 is made of resin, and the two rolling element guide portions 23 and 23 are arranged on both surfaces of the inner race portion 7. This rolling element guide part 23 is annular like the rolling element guide part 9 of the first embodiment, and a plurality of movable range restricting holes 23a are provided on the same circumference and at equal positions in the circumferential direction. . The hole diameters of these movable range restricting holes 23a are all the same. The rolling element guide portions 23 and 23 are fixed to the inner member 3 such as the inner race portion 7 or the inner case portion 6 by fixing means such as screws. Therefore, the separate rolling element guide portion 23 restricts the movable range of the ball 8 to a circular range having a predetermined radius, like the rolling element guide portion 9 of the first embodiment. Thus, if the rolling element guide part 23 is a separate body, the rolling element guide part can be formed of a different material such as resin, which is useful for cost reduction and weight reduction.
[0034]
FIG. 4 is a cross-sectional view of the bearing 30 according to the third embodiment of the present invention (the description of the lower half of the shaft center is omitted). In the bearing 30, the outer race portion 5 and the outer case portion 4 of the outer member 2 are integrated as in the bearing 20 according to the second embodiment, but unlike the bearing 20, the ring shape in the second embodiment. The portion of the outer case 22 also has outer integrated members 31, 31 that are integrated. Further, the bearing 30 uses an inner integrated member 32 in which the inner race portion 7 and the inner case portions 6 and 6 are integrated. Accordingly, the number of parts is further reduced as compared with the bearing 20 according to the second embodiment, which is more preferable in that the axial thickness of the bearing can be reduced. However, it is disadvantageous from the viewpoint of weight reduction as described above. That is, from the viewpoint of weight reduction, as in the bearing 1 according to the first embodiment, the inner race portion 7 and the inner case portion 6 are separated, and the outer case portion 4 and the outer race portion 5 are separated. It is good to do.
[0035]
In the bearing 30, the resin rolling element guide portion 33 is configured to have a shielding effect. That is, the axially outer side surface of the rolling element guide portion 33 is brought close to the raceway surface of the outer integrated member 31, and the axial gap Y (see FIG. 4) between the two is made minute. The outer integrated member 31 has a step 34 at a portion radially inward of the raceway surface on which the balls 8 roll, and has an annular thin portion 35 radially inward of the step 34. Since the axial gap Y between the annular thin portion 35 and the rolling element guide portion 33 is very small, a shielding effect is achieved. With such a configuration, there is no need to provide a separate shield 13 as in the bearing 1 in the first embodiment, so the number of parts is further reduced. Moreover, the bearing 30 is lightened by making the part which plays the role of a shield among the outer integrated members 31 into the thin annular thin part 35.
[0036]
Also in this bearing 30, two rolling element guide portions 33, 33 are provided as in the bearing 20, and these rolling element guide portions 33, 33 are made of a resin separate from the inner integral member 32, etc. The inner integral member 32 is fixed by an appropriate means such as a screw. The rolling element guide portions 33 and 33 are annular like the rolling element guide portion 9 of the first embodiment, and a plurality of movable range restricting holes 33a are provided on the same circumference and at equal positions in the circumferential direction. . The hole diameters of these movable range restricting holes 33a are all the same. Accordingly, the separate rolling element guide portions 33, 33 restrict the movable range of the ball 8 to a circular range having a predetermined radius, like the rolling element guide portion 9 of the first embodiment. In the bearing 30, for example, a preload adding screw or the like may be separately provided so that the two outer integrated members 31, 31 are not separated.
[0037]
When the bearing according to the present invention is used as an assembly member attached to another external member other than the bearing, there is a means for restricting the movement range using a reaction force such as rubber or a spring in the external member, If the range restricted by this is a range narrower than the possible eccentric range of the bearing, the bearing will not interfere with each other.
[0038]
In the above embodiment, the outer member 2 is arranged on the radially outer side and the inner member 3 is arranged on the radially inner side of the outer member 2, but conversely, the outer member 2 is arranged on the radially inner side. The inner member 3 may be disposed on the radially outer side of the outer member 2. In this case, the annular inner race portion 7 of the inner member 3 is provided so as to protrude radially inward from the inner case portion 6. In the above embodiment, the rolling element guide portion 9 is fixed to the inner member 3. However, the rolling element guide portion 9 may be fixed to the outer member 2.
[0039]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a double-row eccentric thrust bearing that is capable of relative movement for a certain distance and that has very little loss during relative movement.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an eccentric thrust bearing according to a first embodiment of the present invention.
FIG. 2 is a sectional view of an eccentric thrust bearing according to a first embodiment of the present invention. FIG. 3 is a sectional view of a bearing according to a second embodiment of the present invention.
FIG. 4 is a sectional view of a bearing according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bearing 2 Outer member 3 Inner member 4 Outer case part 5 Outer race part 6 Inner case part 7 Inner race part 8 Ball 9 Rolling element guide part 9a Movable range control hole 13 Shield 20 Bearing 21 Outer integrated member 23 Rolling element guide part 30 Bearing 31 Outer integrated member 32 Inner integrated member 33 Rolling body guide portion M Radial clearance distance R between the outer peripheral surface of the rolling guide portion and the outer member Clearance distance L between the ball and the inner peripheral surface of the movable range regulating hole Radial clearance distance X between the radially innermost end surface of the outer member and the inner member Axial clearance between the axially outer surface of the rolling element guide portion and the outer race portion raceway surface

Claims (5)

Two annular outer members concentrically facing each other and integrally joined;
An annular inner member interposed between these two outer members concentrically,
Each of the two outer members has an annular outer case portion and an annular plate-like outer race portion attached to the inner surface of the outer case portion,
The inner member has an annular inner case portion, and an annular plate-shaped inner race portion extending in a radial direction from the inner case portion, and
A plurality of rolling elements in each row in a double row sandwiched between the two outer race portions facing both surfaces of the inner race portion;
An annular member fixed to the inner member or the outer member , and a double row eccentric thrust bearing comprising a rolling element guide portion that regulates a movable range of each rolling element within a predetermined range ,
The rolling element guide portion is provided with three or more circular movable range restricting holes on the same circumference and at equal positions in the circumferential direction, and one rolling element per one of the movable range restricting holes. Has been placed,
The axial center of the inner race portion coincides with the axial center of the bearing, and the bearing is configured to be symmetrical on both sides with respect to a plane passing through the axial center and perpendicular to the axis. Double row eccentric thrust bearing. 2. The double-row eccentric thrust bearing according to claim 1, wherein the movable range of the rolling element in the radial direction is half of a relative movable range generated by a radial clearance between the outer member and the inner member . The radial movement distance of the rolling element restricted by the rolling element guide part is substantially equal to the radial width of the inner race part or the outer race part,
The inner case portion and the inner race portion are separate from each other, and the inner race portion is integrally joined while being sandwiched between the two inner case portions,
The double row eccentric thrust bearing according to claim 1 . The double-row eccentric thrust bearing according to claim 3 , wherein the inner race portion and the outer race portion are made of a ferrous metal, and the outer case portion and the inner case portion are made of a light metal . It is fixed to the axially outer end portion of the inner case portion, and extends from the radial direction outer surface along the axial outer surface of the outer case portion, and slightly from the axial outer surface of the outer case portion. The double row eccentric thrust bearing according to any one of claims 1 to 4, further comprising a shield arranged so as to overlap with a gap .

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