JP2009068669A - Radial needle bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure capable of preventing circumferential edge parts of cage elements 17a, 17a constituting a split type cage 7a from easily scratching a lubricant adhering to an outer ring raceway. <P>SOLUTION: Inclined surface parts 18, 18 each inclined in a direction headed toward an inner diameter side as it approaches an edge are formed at both circumferential ends of the outer peripheral surfaces of both the cage elements 17a, 17a. By the presence of gap spaces based on the presence of the respective inclined surface parts 18, 18, both the circumferential edges of both the cage elements 17a, 17a are prevented from scratching a lubricant adhering to the outer ring raceway even in the state where both the circumferential ends of the outer peripheral surfaces of both the cage elements 17a, 17a contacts the outer ring raceway, and the above problem is solved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement in a radial needle bearing incorporated in a rotary machine device such as a manual transmission for an automobile (including a so-called SMT automated based on a manual transmission). Specifically, by devising the structure of the cage, the amount of lubricating oil intervening in the rolling contact portion between the rolling surface of each needle and the outer ring raceway can be secured sufficiently. This makes it possible to improve the performance of various rotary machine devices such as transmissions.

  Conventionally, manual transmissions for automobiles have a structure as shown in FIG. 6, for example, as described in Patent Document 1, and a gear 1 for transmission can be freely rotated around a power transmission shaft 2 by a radial needle bearing 3. I support it. The radial needle bearing 3 has a cylindrical outer ring raceway 4 provided on the inner peripheral surface of the transmission gear 1 which is an outer ring equivalent member, and a cylindrical shape provided on the outer peripheral surface of the power transmission shaft 2 which is an inner ring equivalent member. A plurality of needles 6 are provided between the inner ring raceway 5 and the inner ring raceway 5 so as to roll freely while being held by a cylindrical cage 7. The inner ring raceway 5 may be provided directly on the outer peripheral surface of the power transmission shaft 2 or may be provided on the outer peripheral surface of a separately provided cylindrical inner ring. Further, on the side of the transmission gear 1, there are provided engaging teeth 8 for constituting a synchro mechanism.

  The cage 7 is, for example, an integral type as shown in FIG. 7 or a split type as shown in FIG. Regardless of the structure, the cage 7 is arranged with a gap in the circumferential direction between a pair of rim portions 9, 9 arranged concentrically with a gap in the axial direction. The plurality of pillar portions 10 and 10 are provided in a state of being spanned. The spaces surrounded by the four circumferences by the column parts 10 and 10 adjacent to each other in the circumferential direction and the two rim parts 9 and 9 are pockets 11 and 11 for holding the needles 6 so as to be able to roll. . In addition, notch-shaped recesses 12 and 12 are formed on the outer edge portions of the rim portions 9 and 9 as necessary, and the lubricating oil supplied to the inner diameter side of the retainer 7 is outer diameter. It can be sent to the side.

  In the case of an automotive manual transmission, the transmission gear 1 includes a step portion 13 formed on the outer peripheral surface of the power transmission shaft 2 and a synchro hub 14 that is spline-engaged with the outer peripheral surface of the power transmission shaft 2. Located between. The synchro hub 14 and the engaging teeth 8 are included to constitute a synchro mechanism. When the synchro mechanism is not coupled, relative rotation between the transmission gear 1 and the power transmission shaft 2 becomes free, and the transmission gear 1 does not contribute to power transmission. On the other hand, when the synchro mechanism is coupled, the speed change gear 1 and the power transmission shaft 2 are rotated in synchronization with each other, and the speed change gear 1 contributes to power transmission. The configuration and operation of such a synchro mechanism are well known in the art and are not related to the gist of the present invention.

  The radial needle bearing 3 provided between the speed change gear 1 and the power transmission shaft 2 as described above does not connect the synchro mechanism, and the speed change gear 1 does not contribute to power transmission. The transmission gear 1 and the power transmission shaft 2 are relatively rotated at a high speed. In this state, naturally, it is necessary to distribute a sufficient amount of lubricating oil to the radial needle bearing 3 portion. On the other hand, in a state where the transmission gear 1 contributes to power transmission, the radial needle bearing 3 does not need to allow relative rotation between the transmission gear 1 and the power transmission shaft 2. However, in this state, a minute reciprocating slip occurs at each contact portion between the rolling surface of each needle 6 and the outer ring raceway 4 and the inner ring raceway 5. In order to prevent the occurrence of fretting at these contact portions regardless of such a small reciprocating slip, the synchro mechanism is coupled so that the transmission gear 1 and the power transmission shaft 2 are synchronized. Even in a rotating state, it is necessary to circulate a sufficient amount of lubricating oil through the radial needle bearing 3 portion.

  For this reason, conventionally, as described in Patent Document 1, recesses 12 and 12 are formed on the outer edges of the rim portions 9 and 9 constituting the retainer 7, and the inner side of the power transmission shaft 2 is formed. A lubricating oil supply passage 15 formed at the center was formed. Then, the outer end portion of the branch flow path 16 that is passed through the inner end portion of the supply passage 15 is opened toward the radial needle bearing 3. When the automobile is running, lubricating oil is fed into the supply passage 15 based on the action of a pump incorporated in the transmission, and is fed into the radial needle bearing 3 through the branch passage 16 to lubricate the radial needle bearing 3. To do. For this reason, under a general use condition, a sufficient amount of lubricating oil can be circulated in the radial needle bearing 3 regardless of whether or not the synchro mechanism is coupled.

  By the way, in the case of the cage 7 incorporated in the radial needle bearing 3 for a manual transmission for an automobile, a cage type structure as shown in FIG. 8 is used as compared with an integral type as shown in FIG. Use is advantageous from the viewpoint of cost reduction and prevention of fretting. That is, the cage 7 is more advantageous in terms of reducing the material cost and improving performance by reducing the weight, when it is made by injection molding synthetic resin, rather than by pressing or cutting a metal material. It is. If the split mold structure is adopted, when the synthetic resin is manufactured by injection molding, the mold for this injection molding is comparatively (the integral type retainer as shown in FIG. 7 is injection molded. Compared to the case) Also, in the case of a split type cage, a gap is interposed between the circumferential end surfaces of a pair of cage elements, so that the cage can be operated even when the outer ring equivalent member and the inner ring equivalent member do not rotate relative to each other. It is displaced in the circumferential direction (alternating pairs of cage elements). And since the rolling surface of each needle held by this cage and the outer ring raceway and the inner ring raceway can be displaced relative to each other, it is advantageous in terms of preventing fretting as compared with the case of using an integral cage. is there.

  However, when the split type cage 7 is simply used, the synchro mechanism is not coupled and the transmission gear 1 and the power transmission shaft 2 rotate relative to each other. There is a possibility that the lubricating oil present on the outer ring raceway 4 provided on the inner peripheral surface is insufficient. The reason for this is as follows. In the radial needle bearing 3, it is necessary to regulate the radial position of the cage 7 in order to prevent the cage 7 from vibrating by suppressing the radial displacement of the cage 7 during operation. There is. In the case of the split type structure, this restriction must be performed by so-called outer ring guidance in which the outer peripheral surface of the cage 7 and the outer ring raceway 7 are brought into sliding contact or close to each other.

  With such an outer ring guide structure, out of both circumferential edges of the semi-cylindrical cage element 17 constituting the split cage 7, the edge of the cage element 17 on the front side in the rotational direction However, as shown exaggeratedly in FIG. In the case of the conventional structure, both end edges in the circumferential direction of the retainer element 17 were simply planes existing in the radial direction of the retainer element 17, so that the end edge on the front side in the rotational direction was The lubricating oil adhering to the outer ring raceway 4 is scraped off. As a result, there is a shortage of lubricating oil present in the rolling contact portion between the outer ring raceway 4 and the rolling surface of each needle (see FIG. 6), and the durability of the radial needle bearing 3 may be impaired.

  In particular, when the cage element 17 is made of a synthetic resin, the amount of thermal expansion of the cage element 17 when the temperature rises is made of an iron-based alloy such as the transmission gear 1 (see FIG. 6). There is a possibility that the amount of thermal expansion of the member having the outer ring raceway 4 is larger than that, and the contact pressure of the outer circumferential surfaces of both ends of the cage element 17 on the outer ring raceway 4 is increased. In such a state, the force required to rotate the cage element 17 increases, and not only the rotational resistance (dynamic torque) of the radial needle bearing 3 increases, but also the lubricating oil present in the rolling contact portion. The lack of becomes more prominent.

CD-ROM of Japanese Utility Model No. 5-15981 (Japanese Utility Model Application No. 6-69439)

  In view of the circumstances as described above, the present invention realizes a radial needle bearing in which the circumferential edge of the cage element constituting the split type cage is difficult to scrape off the lubricant adhering to the outer ring raceway. Invented accordingly.

The radial needle bearing of the present invention includes an outer ring-equivalent member, an inner ring-equivalent member, a plurality of needles, and a cage, similarly to the previously known radial needle bearing.
Among these members, the outer ring equivalent member is a cylindrical outer ring or a transmission gear constituting an automobile manual transmission, and a cylindrical outer ring raceway is provided on the inner peripheral surface.
The member corresponding to the inner ring is a cylindrical inner ring or a power transmission shaft constituting a manual transmission for an automobile, and a cylindrical inner ring raceway is provided on the outer peripheral surface.
Each of the needles is provided between the inner ring raceway and the outer ring raceway so as to roll freely.

Further, the retainer is for holding the needles, and is a split type in which both circumferential edges of a plurality of retainer elements, each of which is a partial cylindrical shape, abut or face each other. . And in the state which combined these each cage | basket element, it arrange | positioned mutually concentrically in the state which opened the space | interval in the axial direction, respectively, and a pair of rim | limb parts which are each annular | circular shaped, Between these rim | limb parts, And a plurality of pillars arranged at intervals in the circumferential direction. Further, spaces surrounded by the four circumferences by the column portions adjacent to each other in the circumferential direction and the two rim portions are used as pockets for holding the respective needles in a freely rollable manner.
In particular, in the radial needle bearing of the present invention, inclined surface portions that are inclined in the direction toward the inner diameter side toward the end edge are provided at both ends in the circumferential direction of the outer peripheral surface of each cage element.
In the case of carrying out such a radial needle bearing of the present invention, preferably, each cage element is made of a synthetic resin as described in claim 2.

  According to the present invention configured as described above, it is possible to improve the durability of the radial needle bearing with a structure including a split type cage that is manufactured at low cost and is effective in preventing fretting. That is, since there are inclined surface portions at both ends in the circumferential direction of the outer peripheral surface of each cage element constituting the cage, lubricating oil is placed between the front edge of the rotational direction of each cage element and the outer ring raceway. A wedge-shaped gap space that is easy to capture is formed. Lubricating oil adhering to the outer ring raceway during the rotation of each cage element is not scraped off by the front edge in the rotation direction of each cage element, and between the outer peripheral surface of each cage element and the outer ring raceway. Get in. As a result, a sufficient amount of lubricating oil can be secured in the rolling contact portion between the outer ring raceway and the rolling surface of each needle, and high performance of various rotary machine devices such as an automotive manual transmission can be achieved. it can.

  1 to 5 show an example of an embodiment of the present invention. The feature of the present invention is a structure using a split type cage, in order to prevent the front end edge of the cage element constituting the cage from scraping off the lubricant adhering to the outer ring raceway. In the structure. Since the structure and operation of the other parts are the same as those of the radial needle bearings incorporated in various conventionally known rotary support parts including the conventional structure described above, the illustration and explanation of the equivalent parts are omitted or simplified. In the following, the characteristic part of the present invention will be mainly described.

  As in the second example of the cage 7 having the conventional structure shown in FIG. 8 described above, the cage 7a of this example is also made by injection molding a synthetic resin, as shown in FIG. A pair of retainer elements 17a and 17a, which are shaped like a combination, are combined. Inclined surface portions 18 and 18 as shown in detail in FIGS. 2 to 4 are provided on the outer peripheral surfaces of both ends in the circumferential direction of both the cages 17a and 17a. Each of these inclined surface portions 18 and 18 is inclined in the direction toward the inner diameter side toward the circumferential edge of both the cages 17a and 17a.

The shape of each of the inclined surface portions 18 and 18 is not limited to a single flat surface as shown in the figure, but includes a convex curved surface, a stepped surface, etc. As long as the gap space 21 is interposed between them. Even when the main portion of each of the inclined surface portions 18 and 18 is a single flat surface, the continuous portion 22 between the main portion and the outer peripheral surface 19 of the cage 17a, the circle between the main portion and the cage 17a. The continuous part 23 with the circumferential end face 20 is preferably a convex curved surface. Further, with respect to the circumferential length L ₁₈ (see FIG. 2) of each of the inclined surface portions 18, 18, the inclined surface portions 18, 18 exist in the pocket 11 existing at the circumferential end of the cage element 17 a. It is also possible to make it larger (longer than in FIG. 2) within a range that does not reach.

  The radial needle bearing of the present invention incorporating the cage 7a, which is a combination of the pair of cage elements 17a and 17a each having the above-described configuration, can be configured at low cost and has rotational resistance when the temperature rises. It does not rise and has excellent durability. That is, as the retainer 7a, a split type that combines the retainer elements 17a and 17a is used, so that the retainer 7a can be manufactured at low cost. Moreover, even when the outer ring equivalent member such as the transmission gear 1 and the inner ring equivalent member such as the power transmission shaft 2 rotate synchronously, the cage elements 17a and 17a are displaced little by little in the circumferential direction. To prevent fretting.

  Furthermore, in the case of the radial needle bearing of the present invention, the inclined surface portions 18 and 18 are present at both circumferential ends of the outer peripheral surfaces of the retainer elements 17a and 17a constituting the retainer 7a. Between the front end edges in the rotational direction of the cage elements 17a and 17a and the outer ring raceway 4, a wedge-shaped gap space 21 is formed so that lubricating oil can be easily taken in. The lubricating oil adhering to the outer ring raceway 4 during the rotation of the cage elements 17a, 17a is not scraped off at the front edge in the rotation direction of the cage elements 17a, 17a, and the cage elements 17a, 17a. Between the outer ring surface and the outer ring raceway 4. As a result, a sufficient amount of lubricating oil can be secured in the rolling contact portion between the outer ring raceway 4 and the rolling surface of each needle 6 (see FIG. 6), and various rotary machine devices such as an automotive manual transmission can be obtained. High performance can be achieved.

  In particular, even when the outer peripheral surfaces of both ends in the circumferential direction of the cage elements 17a, 17a made of synthetic resin are pressed against the outer ring raceway 4 due to thermal expansion accompanying a temperature rise, the lubrication that has been taken into the gap space 21 Oil passes through the sliding contact portion between the outer peripheral surface of the end portion and the outer ring raceway 4 by a wedge action, and is sent to each of the rolling contact portions. At this time, the sliding contact portion is also lubricated. For this reason, when both the cage elements 17a and 17a are made of synthetic resin, in addition to being able to feed a sufficient amount of lubricating oil to the rolling contact portions even when the temperature rises, the frictional resistance of the sliding contact portions Is kept low. As a result, the durability of the radial needle bearing can be ensured and the rotational resistance can be suppressed.

  The present invention can be applied not only to a manual transmission for automobiles but also to a radial needle bearing incorporated in a rotation support portion of various rotary machine devices, and can contribute to performance improvement centering on durability. In carrying out the present invention, it is advantageous to make the cage made of a synthetic resin from the viewpoint of reducing the material cost and improving the performance by reducing the weight. However, even if the present invention is applied to a radial needle bearing provided with a metal cage, a performance improvement effect can be obtained. Furthermore, in the present invention, it is essential to use a split type retainer, but the number of splits is not limited to two and may be three or more.

The perspective view which shows one example of embodiment of this invention. The partial expansion perspective view which shows typically the A section of FIG. The figure which looked at the upper end part of FIG. 2 from the outer diameter side. The figure seen from the lower part of FIG. The side view which shows typically the part which looked at the outer ring | wheel and the holder | retainer from the axial direction in order to demonstrate the effect | action and effect of this invention. The fragmentary sectional view which shows one example of the manual transmission for motor vehicles incorporating the radial needle bearing used as the object of this invention. The perspective view which shows the 1st example of the holder | retainer integrated in a radial needle bearing. The perspective view which shows the 2nd example. The side view which shows typically the part which looked at the outer ring | wheel and the holder | retainer from the axial direction in order to demonstrate the inconvenience which arises in the case of this 2nd example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shifting gear 2 Power transmission shaft 3 Radial needle bearing 4 Outer ring raceway 5 Inner ring raceway 6 Needle 7, 7a Cage 8 Engagement tooth 9 Rim part 10 Column part 11 Pocket 12 Recessed part 13 Step part 14 Synchro hub 15 Supply path 16 Branch Flow path 17, 17a Cage element 18 Inclined surface portion 19 Outer peripheral surface 20 Circumferential end surface 21 Crevice space 22 Continuous portion 23 Continuous portion

Claims (2)

  An outer ring equivalent member provided with a cylindrical outer ring raceway on the inner peripheral surface, an inner ring equivalent member provided with a cylindrical inner ring raceway on the outer peripheral surface, and a rollable portion provided between the outer ring raceway and the inner ring raceway. A plurality of needles and a holder for holding the needles are provided, and the holders are in contact with or adjacent to each other at both circumferential edges of a plurality of cage elements each having a partial cylindrical shape. A pair of rim portions that are concentric with each other in a state of being spaced apart in the axial direction in a state in which these cage elements are combined, A plurality of pillars arranged at intervals in the circumferential direction between the rim parts, and a space surrounded by the circumference by the pillar parts adjacent to each other in the circumferential direction and the two rim parts. As a pocket to hold each needle for free rolling In the radial needle bearing according to the present invention, a radial surface characterized in that inclined surface portions that are inclined toward the inner diameter side toward the end edge are provided at both ends in the circumferential direction of the outer peripheral surface of each cage element. Needle bearing.   The radial needle bearing according to claim 1, wherein the pair of cage elements are made of synthetic resin.

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