JP2007046792A - Roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a needle roller bearing which increases load capacity and extending a service life without increase in the size of a reduction gear and also with little change in the present design of the reduction gear. <P>SOLUTION: A connection part 16e of a cage 16 is provided radially outward from an axis of a roller 16a. A circumferential distance between the rollers 16a can thereby be shortened to a minimum, and, for instance, the diameter and number of the rollers 16a are increased. Consequently, the load capacity of the needle roller bearing is increased, and the service life is extended. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a roller bearing, to a large load capacity of the roller bearing used in particular reduction gear for decelerating the rotation of the hydraulic motor provided on a construction machine.

  In construction machines such as power shovels, a hydraulic pump is generally driven by using an internal combustion engine as a power source, and various hydraulic cylinders connected to buckets and arms are operated based on the hydraulic pressure generated from the hydraulic pump. , Excavation and other operations can be performed. On the other hand, the hydraulic pressure generated from the hydraulic pump is transmitted to the hydraulic motor and converted into rotational torque, and the rotational torque is amplified by the speed reducer to rotate and move the crawler which is an endless track. Thus, a power shovel or the like can be driven.

  By the way, in general crawler type power shovels and the like, it is sufficient that the traveling speed is relatively low, but it is required to have the ability to run on rough roads and muddy grounds or climb steep slopes, etc. The power needs to be low rotation and high torque. On the other hand, the power generated from the hydraulic motor is generally high rotation and low torque.

  Therefore, a reduction gear is arranged in the power transmission path between the hydraulic motor and the traveling device so as to increase the torque. As such a speed reducer, a speed reducer capable of transmitting power at a high speed reduction ratio by using an eccentrically moving disk has been developed. Since the speed reducer is lightweight and compact, it is suitable for mounting on a crawler vehicle or the like.

  Further, in such a reduction gear, a needle roller bearing is provided that supports the shaft member and the hole member so as to be rotatable relative to each other. 8 to 10 are views showing a needle roller bearing according to the prior art, FIG. 8 is a cross-sectional view of a needle roller bearing including a roller and a cage, FIG. 9 is a front view of the cage, and FIG. Fig. 10 is a view of the cage of Fig. 9 taken along the line XX and viewed in the direction of the arrow.

  In FIG. 8, 16 needle-shaped rollers 401 arranged in the circumferential direction are held at equal intervals by a holder 402. As shown in FIG. 10, the cage 402 is formed by arranging two circular flange portions 402a and 402b in parallel and connecting each other by a connecting portion 402c. Even when a high load is applied to the bearing, the connecting portion 402c functions so as to restrict the free movement of the needle rollers 401 and maintain the distance between the rollers at a constant interval. Therefore, the retainer 402 has a highly rigid structure formed using metal so that such a function can be achieved.

  Furthermore, as is apparent from FIG. 10, each connecting portion 402c includes a central portion 402e that is recessed inward in the radial direction and shoulder portions 402d on both sides thereof. Further, as apparent from FIG. 8, the interval between the adjacent central portions 402e is smaller than the outer diameter of the needle-shaped rollers 401, and the interval between the adjacent shoulder portions 402d is also outside the needle-shaped rollers 401. It is smaller than the diameter.

  As is apparent from this configuration, the needle-shaped roller 401 is firmly held by the cage 402. For example, when the needle-shaped roller bearing is assembled during assembly, the needle-shaped roller 401 is not prepared from the cage 402. It is configured not to fall down.

  By the way, for example, there is a case where it is desired to extend the life or to transmit a large load while maintaining the current size of the reduction gear. In such a case, the load on the bearing also increases, so some countermeasure is necessary. On the other hand, it is possible to increase the load capacity of the bearing by increasing the bearing size and using a roller with a large diameter or increasing the number of rollers, but this increases the size of the bearing, and consequently There is a problem that the size of the reduction gear becomes large.

  On the other hand, in order to increase the load capacity, there is also an idea of increasing the number of bearings (for example, double use). However, in this aspect, there arises a problem that the axial length of the speed reducer increases.

In view of the problems of the prior art, the present invention provides a roller bearing capable of increasing the load capacity and extending the life without increasing the size of the speed reducer and without substantially changing the current design of the speed reducer. The purpose is to provide.

To achieve the above object, the roller bearing of the present invention includes a plurality of rollers, the roller bearing comprising a cage for maintaining said roller at predetermined intervals, wherein the retainer, the outer end faces of said roller And a pair of ring-shaped flange portions parallel to both end faces and a plurality of substantially linear connection portions that connect the pair of ring-shaped flange portions, and the roller is dropped from the cage. Thus, the plurality of connecting portions are arranged with respect to the roller .

According to the needle roller bearing of the present invention, the retainer is located outside the both end surfaces of the roller, and has a pair of ring flange portions parallel to the both end surfaces, and the pair of ring flange portions. Since the plurality of connecting portions are arranged with respect to the rollers so that the rollers are dropped from the cage, the circumferential direction between the rollers is configured. The distance can be shortened as much as possible, whereby the diameter and number of rollers, for example, can be increased, thereby increasing the load capacity of the bearing, thereby extending the service life.

  Hereinafter, a first embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view in the axial direction of a traveling drive hydraulic motor and a reduction gear mounted on a crawler vehicle such as a power shovel. In FIG. 1, a travel drive hydraulic motor and a speed reducer include a housing 1 attached to a crawler vehicle frame (not shown) via a bolt (not shown), and a hydraulic motor 2 disposed in the housing 1. A speed reduction part 3 arranged in series with respect to the hydraulic motor 2, a cylindrical output part 4 arranged radially outward of the speed reduction part 3 and transmitting power for crawler travel to a sprocket (not shown); It is composed of The right side of the output unit 4 in FIG. 1 is closed by a cover C.

  A rotating shaft 5 is rotatably supported by a ball bearing 6 at the center of the housing 1. The rotating shaft 5 is connected to the hydraulic motor 2 and transmits the rotational force generated by the hydraulic motor 2 to the speed reduction unit 3. The hydraulic motor 2 receives hydraulic pressure from a hydraulic pump (not shown) and converts it into rotational force. Since the configuration itself is well known, details are not described below.

  Below, the structure of the deceleration part 3 is demonstrated. A pinion gear 5a is formed on the outer periphery of the right end in FIG. The pinion gear 5a meshes with three intermediate gears 7 arranged at equal intervals in the circumferential direction (only one is shown in FIG. 1). The intermediate gear 7 is attached to the right end of an intermediate shaft 8 (crankshaft) extending in parallel with the rotary shaft 5 and rotates integrally.

  The intermediate shaft 8 is rotatably supported by a pair of tapered roller bearings 10 and 11 with respect to a support member 9 provided radially outward of the rotating shaft 5. On the other hand, the support member 9 rotatably supports the output unit 4 with a pair of large ball bearings 12 and 13. Since the support member 9 is fixed to the housing 1, the intermediate shaft 8 rotates, but its position is fixed to the rotating shaft 5.

  Furthermore, the intermediate shaft 8 forms eccentric portions 8a and 8b which are cylindrical portions eccentric to each other with respect to the axis of the intermediate shaft 8 at the center. The intermediate shaft 8 has the eccentric portions 8a and 8b inserted through the needle roller bearings 16 and 17 of the present invention in the openings 14a and 15a formed in the pair of toothed disks 14 and 15, respectively, so that it can rotate freely. It is supported by.

  FIG. 2 is a view of the configuration of FIG. 1 taken along the line II-II and viewed in the direction of the arrow. In FIG. 2, a toothed disk 15 (14 is also the same) arranged so as to be eccentric with respect to the rotating shaft 5 has a wave-like external tooth 15a composed of a pericycloidal curve on the outer periphery. On the other hand, pins 18 as internal teeth are embedded and arranged at equal intervals on the inner periphery of the output unit 4 so as to face the external teeth 15a. As apparent from FIG. 2, the number of external teeth 15 is one less than the number of pins 18. The toothed disks 14 and 15 are arranged with their eccentric phases shifted by 180 degrees.

  3 is a cross-sectional view of the needle roller bearing according to the present embodiment, FIG. 4 is a front view of the cage, and FIG. 5 is a sectional view of the cage of FIG. FIG. For convenience of explanation, the needle roller bearing 16 will be described below, but the configuration of the needle roller bearing 17 is also the same.

  In FIG. 3, 17 needle-shaped rollers 16a arranged in the circumferential direction are held at equal intervals by a cage 16b. As shown in FIG. 5, the retainer 16 b is formed by arranging two circular flange portions 16 c and 16 b in parallel and connecting each other by a connecting portion 16 e. As is apparent from FIG. 5, each connecting portion 16e has a columnar shape that connects the outer circumferences of the flange portions 16c and 16d in a substantially straight line. Therefore, the column portion as the holding portion extends radially outward from the axis of the needle roller. The retainer 16b has a highly rigid structure formed using metal.

  Next, the operation in the present embodiment will be described below with reference to FIGS. First, oil pumped from a hydraulic pump (not shown) is converted into rotational force by the hydraulic motor unit 2. However, since this rotational force is a high rotational speed and low torque, it is necessary to decelerate in order to obtain power for a crawler vehicle. This is performed in the following deceleration unit 3.

  The rotational force generated in the hydraulic motor unit 2 is transmitted to the intermediate gear 7 through the rotary shaft 5 and the pinion gear 5a. As a result, the intermediate shaft 8 rotates at a rotational speed corresponding to the gear ratio between the pinion gear 5a and the intermediate gear 7. On the other hand, when the intermediate shaft 8 rotates, the eccentric portions 8a and 8b revolve with respect to the axis of the intermediate shaft 8, thereby opening the openings 14a of the toothed disks 14 and 15 via the needle roller bearings 16 and 17, respectively. 15a is pushed, and the toothed disks 14 and 15 also revolve around the axis of the intermediate shaft 8.

  At this time, the external teeth 15a of the toothed disks 14 and 15 perform an operation to get over the pin 18, but the output unit 4 is pushed by this and the pin 18 rotates by one pitch. The external teeth 15a go over one roller when the eccentric portions 8a and 8b revolve once, so the reduction ratio is (number of teeth of the pinion gear 5a / number of teeth of the intermediate gear 7) × (1 / pin 18), and usually a high reduction ratio of about 1:30 to 40 is obtained.

  By the way, in this embodiment, the needle roller bearing shown in FIGS. 3 to 5 is used. In such a needle roller bearing, as shown in FIG. 5, each connecting portion 16e has a columnar shape that connects the outer circumferences of the flange portions 16c and 16d in a substantially straight line. On the other hand, the connecting portion 16e does not exist, whereby the distance between the rollers 16a can be made as close as possible. Accordingly, the roller diameter can be increased accordingly.

Below, the calculation formula regarding the lifetime of the bearing by JISB1518 is shown.
Cr = bm × fc × (i × Lwe × cos α) ^7/9 × Z ^3/4 × Dwe ^29/27 (1)
here,
Cr: Basic dynamic radial load rating of radial roller bearing (N)
bm: Constants relating to materials, etc. fc: Constants relating to the shape of each part, etc. i: Number of rows of rollers Lwe: Effective length of rollers (mm)
α: Nominal contact angle (degrees)
Z: Number of bearing rollers Dwe: Diameter of roller (mm)
It becomes.

Therefore, for example, if the roller diameter is increased by 10%, the basic dynamic radial load rating is 1.1 ^29/27 = 1.093, that is, 9.3%. In this case, the load is the same. If so, the lifetime will be extended accordingly. Further, unlike the prior art (FIG. 8), since the flange portions 16c and 16d are linearly connected by the connecting portion 16e having a uniform thickness, the strength of the cage 16b itself can be increased. Become.

  If the needle roller bearings are configured as in the present embodiment, the rollers 16a may inadvertently fall off from the cage 16b during assembly, but before assembly, all the rollers 16a may be inward in the radial direction. Such a problem can be dealt with by arranging a cylindrical jig Zg (FIG. 3) in contact with the portion in the retainer 16b.

  FIG. 6 is a cross-sectional view of the needle roller bearing 116 according to the second embodiment of the present embodiment. In FIG. 6, the number of rollers 116a is increased, more specifically, 17 is increased by one from the prior art (FIG. 8).

According to the above equation (1), the increase in the number of rollers increases the basic dynamic radial load rating by (17/16) ^3/4 = 1.084, that is, 8.4%. If the load is the same, the life will increase accordingly.

  FIG. 7 is a cross-sectional view of the needle roller bearing 216 according to the third embodiment of the present embodiment. In FIG. 7, the number and diameter of the rollers 116a are increased, and thereby the life can be considerably extended.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate.

According to the roller bearing of the present invention, since the column portion as the holding portion is substantially linear and is provided radially outward from the axis of the roller, the circumferential distance between the rollers is reduced as much as possible. Thus, for example, the diameter and number of the rollers can be increased, thereby increasing the load capacity of the bearing, thereby extending the life.

FIG. 1 is a sectional view in the axial direction of a traveling drive hydraulic motor and a speed reducer for a crawler vehicle such as a power shovel. It is the figure which cut | disconnected the structure of FIG. 1 by the II-II line | wire, and looked at the arrow direction. It is sectional drawing of the needle roller bearing concerning this Embodiment. It is a front view of the holder | retainer concerning this Embodiment. It is the figure which cut | disconnected the holder | retainer of FIG. 4 by the IV-IV line and looked at the arrow direction. It is sectional drawing of the acicular roller bearing 116 concerning 2nd Embodiment of this Embodiment. It is sectional drawing of the needle-shaped roller bearing 216 concerning 3rd Embodiment of this Embodiment. It is sectional drawing of the needle-shaped roller bearing which consists of a roller concerning a prior art, and a holder | retainer. It is a front view of the holder | retainer concerning a prior art. It is the figure which cut | disconnected the holder | retainer of FIG. 9 by XX and looked at the arrow direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Hydraulic motor part 3 Deceleration part 4 Output 5 Rotating shaft 5a Pinion gear 7 Intermediate gear 8 Intermediate shaft 8a, 8b Eccentric part 14, 15 Toothed disk 16, 17 Needle roller bearing 18 pin

Claims (1)

  In a needle roller bearing comprising a plurality of needle rollers and a cage that maintains the needle rollers at a predetermined interval, the cage has a pair of parallel ring-shaped flange portions and an outer periphery of the ring-shaped flange portion. A needle roller bearing characterized by comprising a plurality of substantially linear column parts connected together.

Images