JP2011163479A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent slipping-off of a bearing supporting a rotational shaft for a long period of time. <P>SOLUTION: A male screw part 20F is disposed on an outer peripheral side of a rear end part of a second rotational shaft 20, and a bolt hole 20G is disposed to an end face 20E on a rear end side of the second rotational shaft 20. The retaining member 23 is constituted of: a cover part 23A facing an end face 20E of a second rotational shaft 20 and having a through-hole 23D; and a nut part 23B screwed with the male screw part 20F. The nut part 23B of the retaining member 23 is brought into abutment with an end face 22A1 of an inner ring 22A of a tapered roller bearing 22, by making the nut part 23B of the retaining member 23 be screwed with the male screw part 20F of the second rotational shaft 20, and a rotation prevention bolt 24 inserted into the through-hole 23D disposed to the cover part 23A of the retaining member 23 is screwed into the bolt hole 20G of the second rotational shaft 20. Thereby, the rotation stop bolt 24 prevents the nut part 23B of the retaining member 23 from rotating, and slipping-off of the tapered roller bearing 22 is surely prevented by the retaining member 23. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power transmission device that is mounted on a construction machine such as a wheel loader and transmits a rotation of a hydraulic motor, a torque converter, and the like to a rotating shaft.

  In general, wheel-type construction machines, typically wheel-type excavators and wheel loaders, run on general roads toward work sites by rotating the wheels with a rotation source such as a hydraulic motor or torque converter. Is something that can be done.

  Here, the wheel-type construction machine is usually provided with a rotation source such as a hydraulic motor and a torque converter, and a power transmission device that transmits the rotation of the rotation source to a traveling rotary shaft. The power transmission device is provided between the rotation shaft and the casing, and rotatably supports the rotation shaft provided in the casing, the rotation shaft provided rotatably in the casing and having a power transmission gear mounted thereon. A bearing and a retaining member that is provided on the rotating shaft and retains the bearing in the axial direction are configured.

  In this case, for example, when a helical gear (helical gear) is used as a gear attached to the rotary shaft, the helical gear meshes with other helical gears to Axial load (thrust load) is applied. For this reason, a tapered roller bearing is provided between the rotating shaft to which the helical gear is attached and the casing, and a thrust load is received by the tapered roller bearing.

  Here, the tapered roller bearing is composed of an inner ring attached to the rotary shaft, an outer ring attached to the casing, and a plurality of tapered rollers provided between the inner ring and the outer ring. The shaft is retained in the axial direction by a retaining ring (a retaining ring for shaft) that fits in an annular groove formed on the outer peripheral surface of the rotating shaft.

  However, when a retaining ring is used to prevent the tapered roller bearing from being pulled out, if the tapered roller bearing is distorted by the creep phenomenon by operating the power transmission device for a long time, it is stopped by the suspension. There is a possibility that the wheel may come off from the annular groove of the rotating shaft.

  In addition, the groove width of the annular groove provided on the rotating shaft is set larger than the axial dimension of the retaining ring in order to smoothly attach and detach the retaining ring, and usually between the annular groove and the retaining ring. A relatively large axial gap is formed.

  For this reason, when a thrust load acts on the rotating shaft due to the meshing of the helical gear, this thrust load acts on the retaining ring via the inner ring of the tapered roller bearing, so that the inner ring of the tapered roller bearing becomes in contact with the retaining ring and the annular groove. It moves in the axial direction by the gap between them. As a result, there is a problem that an excessive preload acts on the tapered roller bearing due to the thrust load from the rotating shaft, and the durability of the tapered roller bearing is lowered.

  On the other hand, a male screw part is formed on the outer periphery of the shaft end part, and a nut screwed to the male screw part is brought into contact with the inner ring of the roller bearing through a washer or the like, so that the roller bearing is prevented from being removed in the axial direction. A rotating shaft (axle) having a configuration has been proposed. The rotating shaft includes an annular washer that abuts against the inner ring of the roller bearing, an annular fixing plate that is disposed on the washer and has a plurality of protrusions (inner corners) provided radially inward on the inner peripheral side; And a nut (hexagon nut) that is screwed into the male thread portion of the rotating shaft.

  Then, one pin erected on the washer is fitted into a recess provided on the fixing plate, and each protrusion provided on the fixing plate is engaged with each side on the outer peripheral side of the nut, so that the nut is a male screw portion. (Refer to Patent Document 1).

JP-A-57-33213

  However, in the prior art according to Patent Document 1 described above, since the pin that engages the recess of the fixing plate is provided on the annular washer that is inserted into the male screw portion, it is necessary to set the diameter of the pin small. There is. For this reason, it is difficult to increase the strength of the pin, the pin is easily sheared and broken while the rotating shaft is rotated over a long period of time, and the nut can be securely stopped against the male screw portion of the rotating shaft. However, there is a problem that the roller bearing cannot be securely removed by the nut.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a power transmission device capable of reliably retaining a bearing that supports a rotating shaft for a long period of time.

  In order to solve the above-described problems, the present invention provides a casing, a rotating shaft that is rotatably provided in the casing and has a power transmission gear mounted thereon, an inner ring is mounted on the rotating shaft, and an outer ring is mounted on the casing. The present invention is applied to a power transmission device including a bearing that is attached and rotatably supports the rotating shaft, and a retaining member that is provided on the rotating shaft and retains an inner ring of the bearing in the axial direction.

  The invention according to claim 1 is characterized in that the rotary shaft is provided with a male screw portion extending in the axial direction from the axial end portion toward the bearing on the outer peripheral side, and the axial end surface of the rotating shaft is axially provided. A lid portion in which a through-hole that penetrates in the axial direction is formed at a position facing the end surface of the rotating shaft and facing the shaft hole, and a peripheral portion of the lid portion And a nut portion that abuts against the inner ring of the bearing by being screwed into a male thread portion of the rotating shaft and extending between the lid portion and the rotating shaft. The shaft body is provided so as to be inserted into the through hole of the portion and the shaft hole of the rotating shaft and stop the nut portion from rotating about the rotating shaft.

  According to a second aspect of the present invention, the rotating shaft has a large-diameter portion into which the inner ring of the bearing is fitted, and is positioned closer to the end portion in the axial direction than the large-diameter portion and has a smaller diameter than the large-diameter portion. A small-diameter portion facing the inner ring of the bearing with a gap in the radial direction; a male screw portion of the rotary shaft is provided on an outer peripheral surface of the small-diameter portion; The present invention has a configuration in which a bearing fitting portion that fits into the inner ring of the bearing in a state of being screwed to the male screw portion of the shaft and a bearing end surface abutting portion that abuts on an end surface of the inner ring of the bearing are provided.

  According to a third aspect of the present invention, one of the shaft hole of the rotating shaft and the through hole of the lid portion is provided with n pieces at equal angular intervals on a concentric circle centering on the shaft center of the rotating shaft, and the rotating shaft The other of the shaft hole and the through-hole of the lid portion is configured to provide (n + 1) or (n-1) pieces at equal angular intervals on the concentric circle.

  According to the first aspect of the present invention, the through hole provided in the lid portion of the retaining member in a state where the nut portion of the retaining member is screwed into the male thread portion of the rotating shaft and brought into contact with the inner ring of the bearing. By inserting the shaft body through the shaft hole of the rotary shaft, the nut portion can be stopped by the shaft body. In this case, since the shaft body is inserted into the shaft hole provided extending in the axial direction inside the rotation shaft, the diameter of the shaft body can be set large according to the diameter size of the rotation shaft. Strength can be increased. Therefore, even when the rotating shaft is rotated for a long time, the shaft body is not sheared or broken, and the nut portion of the retaining member can be reliably stopped by the shaft body. As a result, even when a thrust load is applied to the rotating shaft, the inner ring of the bearing that supports the rotating shaft can be reliably retained by the retaining member, and the reliability of the entire power transmission device can be improved.

  According to the invention of claim 2, when the nut portion of the retaining member is screwed into the male screw portion provided on the small diameter portion of the rotating shaft, the bearing fitting portion provided on the outer peripheral side of the nut portion is provided on the bearing. The inner ring can be fitted. Thus, by arranging a part of the nut portion inside the inner ring of the bearing, it is possible to reduce the axial dimension from the end surface of the inner ring of the bearing to the end surface of the lid portion of the retaining member. As a result, when the rotating shaft and the retaining member are accommodated in the casing, the axial dimension of the casing can be shortened, and the weight of the casing can be reduced correspondingly.

  According to the invention of claim 3, since the shaft hole provided in the rotating shaft and the through hole provided in the lid portion of the retaining member are provided on a concentric circle centering on the shaft center of the rotating shaft, By screwing the nut portion of the retaining member into the male screw portion, the shaft hole of the rotating shaft and the through hole of the lid portion can be surely matched (aligned), and the shaft hole is aligned with the through hole and the shaft hole. By inserting the body, the nut portion can be stopped with respect to the rotation shaft.

  In this case, one of the shaft hole and the through hole is provided with an equal angular interval on the concentric circle (where n is a positive integer), and the other of the shaft hole and the through hole is even on the concentric circle. Since (n + 1) or (n-1) pieces are provided with an angular interval, the shaft hole and the through hole are formed while the nut portion of the retaining member is screwed into the male screw portion of the rotating shaft and makes one rotation. It is possible to match at n × (n + 1) locations or n × (n−1) locations. Therefore, when the bearing end surface contact portion of the nut portion contacts the end surface of the inner ring of the bearing, even if the through hole of the lid portion does not coincide with the shaft hole of the rotating shaft, the nut portion is slightly inclined in the loosening direction. By rotating only the shaft hole, the shaft hole of the rotating shaft and the through hole of the lid portion can be reliably matched, and the shaft body can be inserted into the through hole and the shaft hole. As a result, the gap generated between the end surface of the inner ring of the bearing and the bearing end surface abutting portion of the nut portion can be reduced and excessive preload acting on the bearing can be suppressed, so that the durability of the bearing is increased. Therefore, the reliability of the power transmission device can be further enhanced.

It is sectional drawing which shows the power transmission device by the 1st Embodiment of this invention. It is a principal part expanded sectional view which shows the rotating shaft in FIG. 1, a gearwheel, a bearing, a retaining member, a rotation stopping bolt, etc. It is a disassembled perspective view which shows a rotating shaft, a gearwheel, a bearing, a retaining member, a locking bolt, etc. It is an enlarged view which shows the end surface of the rotating shaft which provided the two shaft holes. It is an enlarged view which shows the end surface of the cover part of the retaining member which provided three through-holes. It is an enlarged view which shows the end surface of the cover part of the retaining member which provided one through-hole. It is a principal part expanded sectional view similar to FIG. 2 which shows the rotating shaft, gearwheel, bearing, retaining member, knock pin, etc. by 2nd Embodiment. It is a principal part expanded sectional view similar to FIG. 2 which shows the modification of a retaining member.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a power transmission device according to the present invention will be described in detail with reference to the accompanying drawings.

  First, FIG. 1 to FIG. 6 show a first embodiment of the present invention, in which 1 denotes a power transmission device. Here, the power transmission device 1 is used for a traveling device of a wheel type construction machine such as a wheel loader or a wheel type excavator, for example, and transmits the rotation of a hydraulic motor to an output shaft for driving a wheel (wheel). Is. The power transmission device 1 includes a casing 2, a first rotating shaft 6, a drive gear 10, an intermediate gear 11, an output shaft 12, a driven gear 15, a counter gear 16, a clutch device 18, a brake device 19, and a second gear which will be described later. The rotary shaft 20, the tapered roller bearings 21 and 22, the retaining member 23, the locking bolt 24, and the like are provided.

  Reference numeral 2 denotes a casing that forms an outer shell of the power transmission device 1, and the casing 2 includes a front casing 3 positioned on the front side in the front and rear directions, a rear casing 4 positioned on the rear side, and a rear side of the rear casing 4. The rear cover 5 is attached to the rear cover 5 and generally has a hollow box shape.

  Here, on the upper end side of the front casing 3, there is provided a shaft support portion 3A that supports the front side of the first rotating shaft 6 described later, and in the upper and lower intermediate portions of the front casing 3 described later. A shaft support portion 3B that supports the front side of the second rotating shaft 20 is provided, and a cylindrical portion 3C that supports the front side of the output shaft 12 to be described later is provided on the lower end side of the front casing 3. Yes.

  On the other hand, on the upper end side of the rear casing 4, there are provided a brake accommodating cylinder part 4A that accommodates a brake device 19 described later, and a brake release pressure introduction path 4B that opens to the brake accommodating cylinder part 4A. Further, a shaft support portion 4C that supports the rear side of the second rotary shaft 20 is provided at the upper and lower intermediate portions of the rear casing 4, and the rear portion of the output shaft 12 is provided at the lower end side of the rear casing 4. A shaft support portion 4D that supports the side is provided.

  Further, the rear cover 5 is formed with a shaft support portion 5A that supports the rear end portion of the first rotating shaft 6. A clutch pressure introduction path 5B communicating with an annular groove 6E described later is provided on the upper end side of the rear cover 5, and a lubricating oil introduction path 5C communicating with a lubricating oil path 6D described later is provided at the rear end of the rear cover 5. Is provided.

  Reference numeral 6 denotes a first rotating shaft that is rotatably provided in the casing 2, and the first rotating shaft 6 is supported on the shaft support portion 3 </ b> A of the front casing 3 through the bearing 7 on the front side, and on the rear side. It is supported by the shaft support portion 5 </ b> A of the rear cover 5 via the bearing 8. A shaft spline portion 6A is formed at the front end portion of the first rotating shaft 6, and this shaft spline portion 6A projects forward from the front casing 3 and is splined to a low-speed traveling hydraulic motor (not shown). It is the composition which becomes. Further, a hook-like clutch attachment portion 6B to which a clutch device 18 described later is attached is provided in the vicinity of the bearing 7 in the first rotating shaft 6.

  On the other hand, a clutch pressure passage 6C and a lubricating oil passage 6D are provided in the first rotating shaft 6 so as to penetrate in the axial direction. The front and rear ends of the clutch pressure passage 6C and the front end of the lubricating oil passage 6D are respectively closed by plugs 9, and the rear end of the lubricating oil passage 6D is connected to the lubricating oil introduction passage 5C of the rear cover 5. Open toward.

  In addition, an annular groove 6E is provided on the outer peripheral side of the rear end portion of the first rotary shaft 6 so as to extend over the entire circumference, and the clutch pressure passage 6C of the first rotary shaft 6 and the clutch pressure introduction passage 5B of the rear cover 5 are provided. Are configured to communicate with each other via the annular groove 6E. Further, inside the first rotary shaft 6, there is provided one clutch pressure lead-out path 6F extending in the radial direction from the clutch pressure path 6C toward the clutch device 18, and from the lubricating oil path 6D to each bearing 7, A plurality of lubricating oil lead-out paths 6G extending in the radial direction toward 8 etc. are provided.

  Reference numeral 10 denotes a drive gear integrally formed with the second rotary shaft 20, and the drive gear 10 rotates integrally with the second rotary shaft 20. The drive gear 10 is configured to transmit the rotation of the second rotary shaft 20 to the output shaft 12 via the driven gear 15 by always meshing with a driven gear 15 described later.

  11 is an intermediate gear provided on the second rotary shaft 20 coaxially with the drive gear 10, and the intermediate gear 11 is disposed adjacent to the rear side of the drive gear 10 and is splined to a shaft spline portion 20B described later. Has been. The intermediate gear 11 rotates integrally with the second rotary shaft 20 and always meshes with a counter gear 16 described later.

  An output shaft 12 is arranged in parallel with the second rotary shaft 20 so as to be rotatable in the casing 2, and the output shaft 12 is disposed adjacent to the lower side of the second rotary shaft 20. . Here, the front side of the output shaft 12 is supported by the cylindrical portion 3 </ b> C of the front casing 3 via the bearing 13, and the rear side is supported by the shaft support portion 4 </ b> D of the rear casing 4 via the bearing 14. Then, connection flanges 12A are attached to both front and rear ends of the output shaft 12, the front end side connection flange 12A projects forward from the front casing 3, and the rear end side connection flange 12A is the rear casing 4. Protrudes backward from

  Reference numeral 15 is a driven gear fixedly provided at an intermediate portion in the axial direction of the output shaft 12. The driven gear 15 is formed integrally with the output shaft 12 and rotates integrally with the output shaft 12. In this case, the driven gear 15 is always meshed with the drive gear 10, and the output shaft 12 is configured to always rotate together with the second rotating shaft 20.

  Reference numeral 16 denotes a counter gear provided so as to be rotatable relative to the first rotary shaft 6, and the counter gear 16 always meshes with the intermediate gear 11 attached to the second rotary shaft 20. Here, the counter gear 16 is disposed on the outer peripheral side of the first rotating shaft 6 via the bearing device 17, and extends in the axial direction of the first rotating shaft 6, and the outer periphery of the cylindrical portion 16 A. And a gear portion 16B which is fixed to the side and meshes with the intermediate gear 11.

  In this case, the intermediate gear 11 and the gear portion 16B of the counter gear 16 rotate at a high speed together with the second rotary shaft 20 in a meshed state. Therefore, in order to reduce the noise during meshing, the helical gear (Helical gear).

  Reference numeral 18 denotes a clutch device provided between the clutch mounting portion 6B of the first rotating shaft 6 and the cylindrical portion 16A of the counter gear 16, and the clutch device 18 is, for example, a wet multi-plate clutch. The clutch device 18 is supplied with clutch pressure oil through the clutch pressure passage 6C, the clutch pressure lead-out passage 6F, and the like of the first rotation shaft 6, so that the cylindrical portion 16A of the counter gear 16 and the first rotation shaft 6 are supplied. Are connected, and when the supply of clutch pressure oil is stopped, the connection state between the cylindrical portion 16A of the counter gear 16 and the first rotating shaft 6 is released.

  Reference numeral 19 denotes a brake device provided between the brake accommodating cylinder portion 4A of the rear casing 4 and the cylindrical portion 16A of the counter gear 16, and the brake device 19 is a wet multi-plate type negative brake, for example. Then, the brake device 19 releases the braking force against the counter gear 16 by the supply of the brake release pressure oil through the brake release pressure introduction path 4B of the rear casing 4, and the supply of the brake release pressure oil is stopped. Thus, the braking force is applied to the counter gear 16.

  Next, 20 shows the 2nd rotating shaft provided rotatably in the casing 2, and this 2nd rotating shaft 20 is arrange | positioned in parallel between the 1st rotating shaft 6 and the output shaft 12. FIG. The drive gear 10 is integrally formed and the intermediate gear 11 is attached to the intermediate portion in the axial direction. Here, the front side of the second rotating shaft 20 is supported by the shaft support portion 3B of the front casing 3 via the tapered roller bearing 21, and the rear end side is supported by the shaft of the rear casing 4 via the tapered roller bearing 22. It is supported by the part 4C.

  In this case, the tapered roller bearing 21 is provided between the inner ring 21A fitted to the second rotating shaft 20, the outer ring 21B fitted to the shaft support portion 3B of the front casing 3, and the inner ring 21A and the outer ring 21B. And a plurality of tapered rollers 21C. On the other hand, the tapered roller bearing 22 is provided between an inner ring 22A fitted to the second rotating shaft 20, an outer ring 22B fitted to the shaft support portion 4C of the rear casing 4, and the inner ring 22A and the outer ring 22B. The inner ring 22A is secured in the axial direction using a retaining member 23 described later.

  Further, a shaft spline portion 20A is formed at the front end portion of the second rotating shaft 20, and this shaft spline portion 20A protrudes forward from the front casing 3 and is spline-coupled to a high-speed traveling hydraulic motor (not shown). It is the composition which becomes. On the other hand, a shaft spline portion 20B is formed behind the drive gear 10 in the second rotating shaft 20, and the intermediate gear 11 is spline-coupled to the shaft spline portion 20B.

  Here, as shown in FIGS. 2 and 3, the large diameter with which the inner ring 22 </ b> A of the tapered roller bearing 22 is fitted to the rear end side, which is the rear side of the shaft spline portion 20 </ b> B, of the second rotating shaft 20. A portion 20C and a small-diameter portion 20D that is located closer to the end in the axial direction than the large-diameter portion 20C and has a smaller diameter than the large-diameter portion 20C are provided. Thus, the small diameter portion 20D of the second rotating shaft 20 is formed in the range from the end surface 20E on the rear end side of the second rotating shaft 20 to the large diameter portion 20C, and as shown in FIG. It faces the inner ring 22A of the bearing 22 with a distance A in the radial direction.

  Reference numeral 20F denotes a male screw portion provided on the outer peripheral side of the small-diameter portion 20D of the second rotating shaft 20, and the male screw portion 20F is directed from the end surface 20E on the rear end side of the second rotating shaft 20 toward the tapered roller bearing 22. Extending in the axial direction. And it is the structure which the nut part 23B of the retaining member 23 mentioned later screws together in the external thread part 20F.

  Reference numeral 20G denotes two bolt holes (internal thread holes) as shaft holes provided in the end face 20E on the rear end side of the second rotary shaft 20, and each bolt hole 20G extends from the end face 20E to the second rotary shaft. 20 extends in the axial direction, and a locking bolt 24 to be described later is screwed therein. Here, as shown in FIGS. 2 to 4, each bolt hole 20 </ b> G has a slightly larger diameter than the head 24 </ b> A of the locking bolt 24, and a counterbore that opens to the end surface 20 </ b> E of the second rotating shaft 20. It is configured as a stepped bottomed hole having a hole 20H. In this case, the two bolt holes 20G are arranged on the concentric circle C (see FIG. 4) having a radius B centered on the axial center OO of the second rotating shaft 20 with an equal angular interval D (180 in this case). It is arranged with degree.

  The number of bolt holes 20G provided in the end surface 20E of the second rotating shaft 20 is not limited to two, and the bolt holes 20G have a radius centered on the axial center OO of the second rotating shaft 20. On the concentric circle C of B, n (where n is a positive integer) can be provided with equal angular intervals.

  Next, reference numeral 23 denotes a retaining member used in the present embodiment, and the retaining member 23 is attached to the male screw portion 20F of the second rotating shaft 20 so that the inner ring 22A of the tapered roller bearing 22 is axially moved. It is something to keep in place. Here, as shown in FIGS. 2 and 3, the retaining member 23 includes a disc-shaped lid portion 23 </ b> A that faces the end surface 20 </ b> E of the second rotating shaft 20, and a tapered roller from the peripheral portion of the lid portion 23 </ b> A. The cylindrical nut portion 23 </ b> B extending toward the inner ring 22 </ b> A of the bearing 22 is formed into a covered cylindrical shape having a substantially U-shaped cross-sectional shape as a whole. A female screw portion 23C that is screwed into the male screw portion 20F of the second rotating shaft 20 is formed on the inner peripheral side of the nut portion 23B.

  Further, the cover portion 23A of the retaining member 23 is provided with three through holes 23D penetrating in the axial direction at positions facing the respective bolt holes 20G provided on the end surface 20E of the second rotating shaft 20. ing. Each through hole 23D is formed to have a slightly larger diameter than the head 24A of the locking bolt 24. As shown in FIG. 2, the locking bolt 24 inserted through the through hole 23D of the lid portion 23A When screwed into the bolt hole 20G of the second rotating shaft 20, the head 24A of the locking bolt 24 is configured to be immersed in the through hole 23D.

  In this case, as shown in FIG. 5, the three through holes 23 </ b> D are arranged on the concentric circles C having a radius B centered on the axial center OO of the second rotating shaft 20 (in this case, equal angular intervals E (in this case). Is arranged at 120 degrees. Therefore, while the nut portion 23B of the retaining member 23 is screwed into the male screw portion 20F of the second rotating shaft 20, and the nut portion 23B is rotated once, the bolt hole 20G and the through hole 23D rotate 60 degrees. Each time it is done, it is configured to match (align) in six places, one place at a time.

  The number of through holes 23D formed in the lid portion 23A is not limited to three, and the number of bolt holes 20G provided in the second rotating shaft 20 is n (where n is a positive integer). In this case, (n + 1) or (n-1) through-holes 23D are arranged at equal angular intervals on a concentric circle C having a radius B centered on the axial center OO of the second rotating shaft 20. It can be provided.

  Therefore, as shown in FIG. 6, for the two bolt holes 20 </ b> G provided in the second rotating shaft 20, the lid portion 23 </ b> A may be provided with one through hole 23 </ b> D on the concentric circle C, In this case, the bolt hole 20G and the through hole 23D are configured to coincide with each other at a total of two places each time the nut portion 23B of the retaining member 23 rotates 180 degrees.

  That is, n bolt holes 20G are provided at equal angular intervals on a concentric circle C centered on the shaft center OO with respect to the second rotating shaft 20, and the lid portion 23A of the retaining member 23 is In the case where (n + 1) through holes 23D are provided on the concentric circle C at equal angular intervals, a retaining member for one of the through holes 23D to coincide with one of the bolt holes 20G. The rotational speed P1 of 23 is expressed by the following formula 1.

  Further, n bolt holes 20G are provided at equal angular intervals on a concentric circle C centered on the axis center OO with respect to the second rotating shaft 20, and the lid portion 23A of the retaining member 23 is When (n-1) through-holes 23D are provided on the concentric circle C at equal angular intervals, one of the through-holes 23D is removed to match one of the bolt holes 20G. The rotational speed P2 of the stop member 23 is expressed by the following formula 2.

  Thus, in the present embodiment, when (n + 1) through holes 23D are provided in the lid portion 23A of the retaining member 23, the retaining member 23 is rotated by 1 / {n × (n + 1)}. In the case where one of the through holes 23D can be matched with one of the bolt holes 20G, and (n-1) through holes 23D are provided in the lid portion 23A of the retaining member 23. In this configuration, one of the through holes 23D can be matched with one of the bolt holes 20G while the retaining member 23 is rotated 1 / {n × (n−1)}. ing.

  On the other hand, on the outer peripheral side of the nut portion 23B of the retaining member 23, a bearing fitted to the inner ring 22A of the tapered roller bearing 22 in a state where the nut portion 23B is screwed to the male screw portion 20F of the second rotating shaft 20. A fitting portion 23E and a bearing end surface abutting portion 23F that has a bowl shape larger than the bearing fitting portion 23E and abuts on the end surface 22A1 of the inner ring 22A of the tapered roller bearing 22 are provided. Further, four notches 23G for hooking a tool (not shown) for tightening the retaining member 23 are provided at the outer peripheral edge of the bearing end surface abutting portion 23F with an angular interval of 90 degrees, for example. ing.

  Then, in a state where the inner ring 22A of the tapered roller bearing 22 is fitted to the large diameter portion 20C of the second rotating shaft 20, the nut portion 23B of the retaining member 23 is attached to the male screw portion 20F of the second rotating shaft 20. By screwing, as shown in FIG. 2, the bearing fitting portion 23E of the nut portion 23B is fitted to the inner ring 22A, and the bearing end surface abutting portion 23F of the nut portion 23B is brought into contact with the end surface 22A1 of the inner ring 22A. The inner ring 22A of the tapered roller bearing 22 can be retained in the axial direction.

  In this case, since the male threaded portion 20F of the second rotating shaft 20 is formed in a small diameter portion 20D that faces the inner ring 22A of the tapered roller bearing 22 with a distance A in the radial direction, the nut portion 23B of the retaining member 23 is provided. By engaging with the male screw portion 20F, the bearing fitting portion 23E provided on the outer peripheral side of the nut portion 23B is fitted to the inner ring 22A of the tapered roller bearing 22 with an axial dimension F, and accordingly, the end face of the inner ring 22A. The axial dimension G from 22A1 to the rear end face of the lid 23A of the retaining member 23 can be shortened.

  Reference numeral 24 denotes a single locking bolt as a shaft that is inserted into a through hole 23D provided in the lid 23A of the retaining member 23 and a bolt hole 20G of the second rotating shaft 20, and the locking bolt Reference numeral 24 denotes a stopper for stopping the nut portion 23 </ b> B of the retaining member 23 with respect to the second rotating shaft 20. Here, the locking bolt 24 is composed of a hexagon socket head bolt having a cylindrical head portion 24A, and is screwed into the bolt hole 20G of the second rotating shaft 20 through the through hole 23D of the lid portion 23A.

  Then, the locking bolt 24 is engaged with the through hole 23D provided in the lid portion 23A of the locking member 23 in a state where the locking bolt 24 is in contact with the counterbore 20H of the bolt hole 20G. The nut portion 23 </ b> B of the member 23 is stopped with respect to the second rotation shaft 20. At this time, the head portion 24A of the locking bolt 24 is configured to immerse into the through hole 23D of the lid portion 23A without protruding from the lid portion 23A of the locking member 23.

  The power transmission device 1 according to the present embodiment has the above-described configuration. Hereinafter, the operation of the power transmission device 1 when a wheel loader (not shown) equipped with the power transmission device 1 is traveling will be described.

  First, in a state where the engine and the hydraulic pump (both not shown) are stopped and the supply of the brake release pressure oil from the hydraulic pump to the brake device 19 is stopped, the brake device 19 controls the counter gear 16. Give power.

  As a result, a braking force acts on the second rotary shaft 20 via the intermediate gear 11 meshed with the counter gear 16, and this braking force acts on the output shaft 12 via the driven gear 15 meshed with the drive gear 10. To do. As a result, the output shaft 12 for rotationally driving the wheels of the wheel loader can be kept stopped and the wheel loader can be stopped (parked).

  Next, when the engine and a hydraulic pump (both not shown) are operated, a part of the pressure oil discharged from the hydraulic pump is supplied to the brake device 19 through the brake release pressure introduction passage 4B of the rear casing 4, and the counter The braking force on the gear 16 is released.

  Here, when the wheel loader travels on a general road or the like, it is necessary to rotate the output shaft 12 of the power transmission device 1 at a high speed. In this case, the connection state between the cylindrical portion 16A of the counter gear 16 and the first rotating shaft 6 is released by stopping the supply of the clutch pressure oil to the clutch device 18.

  In this way, the braking force applied to the counter gear 16 by the brake device 19 is released, and the connection between the counter gear 16 and the first rotary shaft 6 by the clutch device 18 is released, whereby the second rotary shaft 20 is A high speed traveling hydraulic motor (not shown) connected to the spline portion 20A rotates at a high speed. Then, the rotation of the second rotary shaft 20 is transmitted to the output shaft 12 via the driven gear 15 meshed with the drive gear 10, and the output shaft 12 corresponds to the gear ratio between the drive gear 10 and the driven gear 15. The wheel loader can be driven at a high speed by rotating at a high speed with a high rotational speed.

  On the other hand, for example, when excavation work is performed such that the wheel loader travels at a low speed and the bucket is pushed into the earth and sand, the output shaft 12 of the power transmission device 1 needs to be rotated at a low speed and with a high torque. In this case, after the clutch pressure oil from the hydraulic pump (not shown) is guided to the clutch pressure introduction path 5B of the rear cover 5, the annular groove 6E provided in the first rotating shaft 6 and the clutch pressure path 6C is supplied to the clutch device 18 through the clutch pressure derivation path 6F, and the cylindrical portion 16A of the counter gear 16 and the first rotating shaft 6 are connected.

  As a result, the rotation of the first rotating shaft 6 connected to the low-speed traveling hydraulic motor (not shown) is transmitted from the counter gear 16 to the second rotating shaft 20 via the intermediate gear 11 and further driven. It is transmitted from the gear 10 to the output shaft 12 via the driven gear 15. As described above, the rotation of the first rotation shaft 6 and the rotation of the second rotation shaft 20 are transmitted to the output shaft 12 in a combined state, and the output shaft 12 rotates at a low speed and a high torque. The wheel loader can be driven at a low speed according to excavation work.

  Here, during the operation of the power transmission device 1 as described above, the counter gear 16 composed of a helical gear attached to the first rotary shaft 6 via the clutch device 18 and the second rotary shaft 20 are attached. Since an axial thrust load acts on the tapered roller bearing 22 that supports the second rotating shaft 20 by meshing with the intermediate gear 11 formed of a helical gear, the inner ring 22A of the tapered roller bearing 22 is It is necessary to ensure the axial removal by the retaining member 23.

  In contrast, in the present embodiment, the external thread portion 20F extending in the axial direction is provided on the outer peripheral side of the rear end portion of the second rotary shaft 20, and the end surface 20E on the rear end side of the second rotary shaft 20 is axially disposed. A bolt hole 20G extending to the end, and the retaining member 23 is confronted with the end surface 20E of the second rotary shaft 20 and has a cover portion 23A in which a through hole 23D is formed in the axial direction. The roller bearing 22 is configured by a nut portion 23B extending toward the inner ring 22A and screwed into the male screw portion 20F.

  Therefore, as shown in FIG. 2, the nut portion 23B of the retaining member 23 is screwed into the male screw portion 20F of the second rotating shaft 20 and brought into contact with the end surface 22A1 of the inner ring 22A of the tapered roller bearing 22. In this state, by inserting a locking bolt 24 into a through hole 23D provided in the lid portion 23A of the retaining member 23 and screwing the locking bolt 24 into the bolt hole 20G of the second rotating shaft 20, The nut portion 23 </ b> B of the retaining member 23 can be stopped by the locking bolt 24.

  In this case, the locking bolt 24 is screwed into a bolt hole 20 </ b> G formed inside the large-diameter second rotating shaft 20, so that the locking bolt 24 depends on the diameter of the second rotating shaft 20. Can be set large, and its strength can be greatly increased. In addition, the strength of the locking bolt 24 can be further increased by subjecting the locking bolt 24 to heat treatment or the like.

  Therefore, even when the second rotary shaft 20 is rotated for a long time, the locking bolt 24 is not sheared or damaged, and the locking bolt 24 securely secures the nut portion 23B of the retaining member 23. It can be stopped. As a result, even when a thrust load acts on the second rotary shaft 20, the inner ring 22A of the tapered roller bearing 22 that supports the second rotary shaft 20 can be reliably retained for a long period of time. The reliability of the entire apparatus 1 can be improved.

  Moreover, in the present embodiment, at the rear end portion of the second rotating shaft 20, a large diameter portion 20C that fits into the inner ring 22A of the tapered roller bearing 22, and a small diameter portion that faces the inner ring 22A with a gap A in the radial direction. 20D, and a male screw portion 20F is provided on the small diameter portion 20D. For this reason, by screwing the nut portion 23B of the retaining member 23 into the male screw portion 20F, the bearing fitting portion 23E provided on the outer peripheral side of the nut portion 23B is connected to the tapered roller bearing 22 as shown in FIG. The inner ring 22A is fitted with an axial dimension F inside.

  As a result, the axial dimension G from the end surface 22A1 of the inner ring 22A to the rear end surface of the lid portion 23A of the retaining member 23 can be shortened. As shown in FIG. And the axial dimension S of the site | part which accommodates the retaining member 23 can be shortened. Therefore, the weight of the casing 2 can be reduced, and the weight of the entire power transmission device 1 can be reduced.

  Further, in the present embodiment, n bolts (where n is a positive integer) with a uniform angular interval on a concentric circle C having a radius B centered on the axial center OO of the second rotating shaft 20. A hole 20G is provided, and the lid portion 23A of the retaining member 23 has (n + 1) pieces at equal angular intervals on a concentric circle C having a radius B centered on the axial center OO of the second rotating shaft 20. Alternatively, (n-1) through holes 23D are provided.

  Therefore, when two bolt holes 20G are provided in the end surface 20E of the second rotating shaft 20 and three through holes 23D are provided in the lid portion 23A of the retaining member 23, the nut portion 23B of the retaining member 23 is The bolt hole 20 </ b> G and the through hole 23 </ b> D can be made to coincide with each other at six locations while being engaged with the male screw portion 20 </ b> F of the second rotating shaft 20 and making one rotation.

  That is, the nut portion 23B of the retaining member 23 is screwed into the male screw portion 20F of the second rotating shaft 20, and the bearing end surface abutting portion 23F of the nut portion 23B contacts the end surface 22A1 of the inner ring 22A of the tapered roller bearing 22. Even when the through-hole 23D of the lid portion 23A and the bolt hole 20G of the second rotating shaft 20 do not coincide with each other when the contact is made, the through-hole 23D is rotated while the nut portion 23B is rotated at most 1/6 in the loosening direction Can be reliably aligned with the bolt hole 20G, and the locking bolt 24 inserted through the through hole 23D can be screwed into the bolt hole 20G.

  Thereby, the amount of movement of the retaining member 23 toward the loose side can be reduced, and the gap generated between the bearing end surface abutting portion 23F of the nut portion 23B and the end surface 22A1 of the inner ring 22A of the tapered roller bearing 22 can be reduced. it can. As a result, the movement of the tapered roller bearing 22 in the axial direction during the rotation of the second rotating shaft 20 can be suppressed to the minimum, and an excessive preload acting on the tapered roller bearing 22 can be suppressed. . Thereby, durability of the tapered roller bearing 22 can be enhanced, and the reliability of the power transmission device 1 can be further enhanced.

  Next, FIG. 7 shows a second embodiment of the present invention. The feature of the present embodiment is that a knock pin is used as a shaft body inserted into the shaft hole of the rotating shaft and the through hole of the locking member. There is. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 7, reference numeral 31 denotes a second rotating shaft according to the present embodiment, and the second rotating shaft 31 is substantially the same as the second rotating shaft 20 according to the first embodiment. The spline-coupled shaft spline portion 31A, the large-diameter portion 31B into which the inner ring 22A of the tapered roller bearing 22 is fitted, and the small-diameter portion 31C having a smaller diameter than the large-diameter portion 31B. The inner ring 22A of the tapered roller bearing 22 faces the inner ring 22A with a distance A in the radial direction. A male screw portion 31E extending in the axial direction from the end surface 31D on the rear end side of the second rotating shaft 31 toward the tapered roller bearing 22 is formed on the outer peripheral side of the small diameter portion 31C.

  Reference numeral 31F denotes two pin holes as shaft holes provided in the end surface 31D on the rear end side of the second rotating shaft 31, and each of the pin holes 31F is replaced with the bolt hole 20G according to the first embodiment. Used in this embodiment. Here, each pin hole 31F extends in the axial direction of the second rotating shaft 31 from the end face 31D, and a knock pin 32 described later is press-fitted. And each pin hole 31F is equally angularly spaced on a concentric circle having a radius B centered on the axial center OO of the second rotating shaft 31 in the same manner as the bolt hole 20G according to the first embodiment. 180 degrees).

  Reference numeral 32 denotes one knock pin as a shaft body inserted through a through hole 23D provided in the lid portion 23A of the retaining member 23 and a pin hole 31F of the second rotating shaft 31, and the knock pin 32 is, for example, It consists of parallel pins that form a uniform cylindrical shape, and prevents the nut portion 23 </ b> B of the retaining member 23 from rotating with respect to the second rotation shaft 31. Further, a female screw hole 32A is formed on one end side of the knock pin 32, and the knock pin 32 press-fitted into the pin hole 31F can be removed by pulling a bolt (not shown) screwed into the female screw hole 32A. It is like that.

  The power transmission device according to the present embodiment includes the second rotating shaft 31 and the knock pin 32 as described above, and the nut portion 23B of the retaining member 23 is screwed onto the male screw portion 31E of the second rotating shaft 31. The knock pin 32 is inserted into the through hole 23D provided in the lid portion 23A of the retaining member 23 in a state where the end surface 22A1 of the inner ring 22A of the tapered roller bearing 22 is brought into contact, and the knock pin 32 is second rotated. Press fit into the pin hole 31F of the shaft 31. Accordingly, the nut portion 23B of the retaining member 23 can be stopped by the knock pin 32, and the retaining member 23 can be reliably retained for a long period of time.

  In the first embodiment described above, the case where the axial dimension (thickness dimension) of the lid portion 23A constituting the retaining member 23 is set to be relatively large is illustrated. However, the present invention is not limited to this. For example, as shown in the modification shown in FIG. 8, the use of the retaining member 23 'in which the axial dimension of the lid portion 23A' is set small allows the tapered roller bearing 22 to be used. The axial dimension G between the end surface 22A1 of the inner ring 22A and the end surface of the lid portion 23A ′ can be further reduced.

  In the first embodiment described above, n bolt holes 20G are provided in the end surface 20E of the second rotating shaft 20, and (n + 1) or (n-1) are provided in the lid portion 23A of the retaining member 23. The case where the through-hole 23D is provided is illustrated.

  However, the present invention is not limited to this, and n through holes 23D are provided in the lid portion 23A of the retaining member 23, and (n + 1) or (n-1) pieces are provided on the end surface 20E of the second rotating shaft 20. The bolt hole 20G may be provided.

  Further, in the above-described embodiment, the power transmission device 1 is illustrated that rotates a hydraulic motor by, for example, pressure oil from a hydraulic pump driven by an engine and transmits the rotation of the hydraulic motor to the output shaft 12. However, the present invention is not limited to this, and can be applied to, for example, a power transmission device that converts the rotation of the engine with a torque converter and transmits the rotation of the torque converter to the output shaft.

  Furthermore, in embodiment mentioned above, although the power transmission device 1 used for the traveling apparatus of a wheel type construction machine was mentioned as an example, this invention is not restricted to this, The rotating shaft with which the gearwheel was attached in the casing, The present invention can be widely applied to a power transmission device provided with a bearing that supports the rotating shaft and a retaining member that retains the bearing.

DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Casing 6 1st rotating shaft 10 Drive gear 11 Intermediate gear 12 Output shaft 15 Drive gear 16 Counter gear 20, 31 2nd rotating shaft 20C, 31B Large diameter part 20D, 31C Small diameter part 20E, 31D End surface 20F, 31E Male thread 20G Bolt hole (shaft hole)
21, 22 Tapered roller bearings 21A, 22A Inner rings 21B, 22B Outer rings 23, 23 'Retaining members 23A, 23A' Cover parts 23B Nut parts 23D Through holes 23E Bearing fitting parts 23F Bearing end face contact parts 24 body)
31F Pin hole 32 Dowel pin (shaft)

Claims (3)

A casing, a rotary shaft rotatably provided in the casing and having a power transmission gear mounted thereon, an inner ring attached to the rotary shaft, and an outer ring attached to the casing to rotatably support the rotary shaft. In a power transmission device comprising a bearing and a retaining member provided on the rotating shaft and retaining an inner ring of the bearing in the axial direction.
The rotating shaft is provided with a male screw portion extending in the axial direction from the end portion in the axial direction toward the bearing on the outer peripheral side thereof, and provided with an axial hole extending in the axial direction on the end surface in the axial direction.
The retaining member includes a lid portion formed with a through-hole facing the end surface of the rotating shaft and facing the shaft hole in the axial direction, and a peripheral portion of the lid portion toward the inner ring of the bearing. And a nut portion that abuts on the inner ring of the bearing by being screwed into a male thread portion of the rotating shaft.
Between the lid part and the rotary shaft, a shaft body is provided which is inserted into the through hole of the lid part and the shaft hole of the rotary shaft and stops the nut part with respect to the rotary shaft. A power transmission device characterized by that. The rotating shaft has a large-diameter portion into which the inner ring of the bearing fits, and is positioned closer to the end in the axial direction than the large-diameter portion and has a smaller diameter than the large-diameter portion. A small-diameter portion that faces with a space therebetween, and the external thread portion of the rotating shaft is provided on the outer peripheral surface of the small-diameter portion,
On the outer peripheral side of the nut portion of the retaining member, a bearing fitting portion that fits into the inner ring of the bearing in a state of being screwed into the male screw portion of the rotating shaft, and a bearing end surface that abuts on an end surface of the inner ring of the bearing The power transmission device according to claim 1, wherein the contact portion is provided. One of the shaft hole of the rotating shaft and the through hole of the lid portion is provided with n pieces at equal angular intervals on a concentric circle centered on the shaft center of the rotating shaft,
3. The configuration according to claim 1, wherein the other of the shaft hole of the rotating shaft and the through hole of the lid portion is configured to provide (n + 1) or (n−1) pieces at equal angular intervals on the concentric circle. Power transmission device.

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