JP2002213568A - Travel unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel unit integrally protruded with a trunnion boss holding a sun gear from a fixed casing and miniaturizable in the axial direction by properly applying detent to a nut fixing a bearing between the fixed casing and a rotary casing. SOLUTION: A bearing 13 inserted into the outer periphery of the fixed casing 11 from one end side to rotatably support the rotary casing 12 is positioned in the axial direction by a nut 61 screwed to the outer periphery of the fixed casing 11, and the travel unit 1 is provided with a key plate 62 applying detent to the nut 61. The key plate 62 is fixed at a position corresponding to the end face 11a of the fixed casing 11 protruded with the trunnion boss 25, and the key plate 62 and a bolt 64 for fixing it to the nut 61 are arranged on the outside of the end face 11a of the fixed casing 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling unit that outputs a rotation of a hydraulic motor at a reduced speed, and more particularly to a traveling unit whose size is reduced in a radial direction.

[0002]

2. Description of the Related Art Among construction machines, a traveling unit is used as a drive unit of a construction machine which travels by a crawler typified by a traveling device of a hydraulic shovel. In this traveling unit, a hydraulic motor is arranged inside a fixed casing fixed to the main body vehicle, and the output rotation is transmitted via a planetary gear mechanism to a rotating casing concentrically and rotatably fitted to the fixed casing, The crawler is driven by a sprocket provided on the outer periphery of the rotating casing. This traveling unit has a space limitation as a whole due to the restriction on the arrangement inside the crawler, and is required to be small and have a high output form.

[0003] Japanese Patent Application Laid-Open No.
One disclosed in JP-A-249297 is known. As shown in FIG. 13, in this reduction gear transmission 101, a hydraulic motor 103 is arranged inside a cylindrical fixed casing 102, and a sun gear 105 is attached to a tip of an output shaft 104 of the hydraulic motor 103. A rotatable casing 107 is rotatably supported on the outer circumference via a bearing 106, and internal teeth 108 are formed on the inner circumference of the rotatable casing 107. The rotation of the first sun gear 105 is controlled by the first planetary gear 1.
09, a second sun gear 111 engaging with the holding frame 110 of the first planetary gear 109, a second planetary gear 112, a third sun gear 114 engaging with the holding frame 113 of the second planetary gear 112,
The internal teeth 1 are provided via a third planetary gear 115 rotatably held by a carrier 116 screwed to the fixed casing 102.
08 to rotate the rotary casing 107 at a reduced speed.

A flange 117 of the fixed casing 102 is bolted to a main body (not shown), and a flange 118 of the rotating casing 107 is attached to the sprocket 11 for crawler.
9 bolted.

The rotational driving force of the hydraulic motor 103 fixed in the fixed casing 102 is the first stage planetary gear mechanism of the first sun gear 105 and the first planetary gear 109, and the second sun gear 111 and the second planetary gear. The speed is reduced through the second stage planetary gear mechanism 113 and the third stage planetary gear mechanism of the third sun gear 114 and the third planetary gear 115, and transmitted to the rotation of the rotary casing 107.

The rotating casing 107 is rotatably supported on the fixed casing 102 via a bearing 106. Since a tapered roller bearing is used for the bearing 106, a predetermined preload is applied to the bearing 106 by tightening the nut 121 with an appropriate torque. In order to maintain a state in which a certain preload is applied to the bearing 106, it is necessary to stop the rotation of the nut 121. Therefore, as shown in FIGS. 14 and 15, a key plate 122 having a key piece 122 a fitted into the key groove 102 a of the fixed casing 102 and a nut 121 are connected to the bolt 12.
The structure which stops at 3 is adopted. Since a large number of screw holes 121a are provided at predetermined intervals on the side surface of the nut 121, the bolt 123 can be screwed by slightly turning the nut 121 that has been properly tightened.

[0007]

However, since the fixed casing 102 is provided with the key groove 102a and the key plate 122 and the head of the bolt 123 are interposed between the bearing 106 and the carrier 116 in addition to the nut 121. However, there has been a problem that the distance t between the nut 121 and the end of the fixed casing 102 becomes long.

The present invention solves such a problem of the prior art, and stops a bearing between a fixed casing and a rotating casing in a traveling unit integrally protruding a trunnion boss holding a sun gear from a fixed casing. An object of the present invention is to provide a traveling unit that can be downsized in the axial direction by properly stopping the rotation of the nut.

[0009]

According to a first aspect of the present invention, there is provided a traveling unit having a fixed casing in which a hydraulic motor is disposed, and a bearing inserted into the outer periphery of the fixed casing from one end thereof. A rotatable casing rotatably supported and having internal teeth on the inner peripheral side, a sun gear attached to an output shaft protruding from the hydraulic motor to the one end, and a sun gear mounted between the sun gear and the internal teeth. A planetary gear mechanism that is provided and decelerates in a plurality of stages, a trunnion boss that is arranged on the one end side of the fixed casing and rotatably supports a final stage planetary gear that meshes with the internal teeth, and a tip of the trunnion boss. A holder that is inserted and attached to the fixed casing, wherein the bearing is axially positioned by a nut screwed onto the outer periphery of the fixed casing, The traveling unit key plate is provided for rotating stopper of bets, it said key plate is characterized in that fixed to a position where the Toranionbosu corresponds to the end surface of the stationary casing which project.

According to the structure of the first aspect, since the planetary gear of the last stage and the key plate can be arranged so as to partially overlap in the axial direction, the traveling unit can be shortened in the axial direction only by the overlapping portion.

According to a second aspect of the present invention, there is provided the traveling unit according to the first aspect, wherein a column protruding from the fixed casing and a column protruding from the holder are fixed in an abutting manner, and the key plate is fixed to the fixed casing. And is fixed to the end face in a state of being partially inserted into a notch provided in the side support. According to this configuration, the notch is provided in the support between the holder holding the tip of the trunnion boss and the fixed casing, and the key plate is arranged. Therefore, the key plate is arranged so as not to interfere with the planetary gear. can do.

According to a third aspect of the present invention, in the traveling unit according to the first or second aspect, the trunnion boss is provided along an outer periphery of the fixed casing. According to this configuration, the outer periphery of the fixed casing can be reduced in diameter along the circumscribed circle of the trunnion boss, so that not only the axial direction but also the radial direction can be reduced.

According to a fourth aspect of the present invention, the traveling unit is rotatably supported via a fixed casing in which a hydraulic motor is disposed, and a bearing inserted into the outer periphery of the fixed casing from one end thereof. A rotary casing having internal teeth, a sun gear attached to an output shaft protruding from the hydraulic motor to the one end side, and a planetary gear mechanism disposed between the sun gear and the internal teeth and reduced in a plurality of stages. A trunnion boss that is disposed on the one end side of the fixed casing and rotatably supports a final stage planetary gear that meshes with the internal teeth, and a holder into which the tip of the trunnion boss is inserted and attached to the fixed casing. A traveling unit that axially positions the bearing with a nut screwed to the outer periphery of the fixed casing,
A pin for stopping rotation of the nut is provided between the nut and the holder.

According to this configuration, the nut and the holder are connected by the pin without using the key plate.
The nut can be prevented from rotating without extending the fixed casing in the axial direction.

According to a fifth aspect of the present invention, there is provided the traveling unit according to the fourth aspect, wherein the column protruding from the fixed casing and the column protruding from the holder are fixed in an abutting manner, and are fixed to the fixed casing side from the holder. A protruding portion is provided to protrude along the outer periphery of the column, and the pin is disposed between the protruding portion and the nut. According to the configuration of the fifth aspect, the holder is inserted toward the fixed casing so that the end surfaces of the columns come into contact with each other, and at the same time, the rotation of the nut is prevented via the pin.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a hydraulic drive reduction device according to a first embodiment of the present invention.

In FIG. 1, a reduction gear 1 has a hydraulic motor 3 built in a fixed casing 11 and a rotating casing 1.
2, a fixed casing 11 is rotatably fitted thereto, and the rotating casing 12 has a built-in two-stage planetary gear type reduction mechanism 2.

The rotating casing 12 is a fixed casing 1
The outer casing 1 is rotatably mounted by a bearing 13 so as not to move in the axial direction, and the rotary casing 12 and the hydraulic motor 3 partially overlap in the axial direction.
A flange 14 for attaching a sprocket (not shown) is provided substantially at the center in the axial direction where the rotary casing 12 and the hydraulic motor 3 are assembled. The bearing 13 and the floating seal 32 are connected to the hydraulic motor 3 of the fixed casing 11.
From the opposite end. Therefore, unless the diameter of the outer periphery on the side of the speed reduction mechanism 2 is particularly reduced, the outer diameters of the bearing 13 and the floating seal 32 increase.

A two-stage planetary gear type speed reducer mechanism 2 is provided inside the rotary casing 12 at one end of the fixed casing 11 so as to obtain a large reduction ratio with as few gears as possible. Internal teeth 15 are formed on the inner periphery of the rotary casing 12, and an output shaft 16 of the hydraulic motor 3 is formed.
A first sun gear 17 is fitted through a spline 18 at the end of the first sun gear 17. Three first planetary gears 20 rotatably supported by the carrier 19 mesh between the first sun gear 17 and the internal teeth 15. The inner periphery of the carrier 19 that transmits the revolution of the first planetary gear 20 around the first sun gear 17 and the outer periphery of the second sun gear 22 are engaged by a spline 21.
One first sun gear 17, three first planetary gears 20, internal teeth 15, and a carrier 19 that also functions as an output shaft constitute a first stage planetary gear mechanism.

Three trunnion bosses 25 are integrally protruded from one end of the fixed casing 11. On the trunnion boss 25, three second planetary gears 26 meshing with the second sun gear 22 and the internal teeth 15 are rotatably supported. A holder 24 having a hole 37 fitted to the tip of the trunnion boss 25 is provided.
The column 7 and the column 28 from the fixed casing 11 abut on a mating surface 29, and the columns 27, 28 are fixed by bolts 30 and positioning pins 31. The second sun gear 22, three second planetary gears 26, and the internal teeth 15 functioning as output shafts constitute a second stage planetary gear mechanism.

With the above configuration, the speed reduction mechanism 2
When the first sun gear 17 is rotated by the drive of the hydraulic motor 3, the first planetary gear 20 meshing with both the first sun gear 17 and the internal teeth 15 rotates between the first sun gear 17 and the carrier 19. Is reduced by the revolution, and the rotation is transmitted to the second sun gear 22 and further the second planetary gear 26
, The rotating casing 12 having the internal teeth 15 rotates at a reduced speed, so that a sprocket (not shown) attached to the flange 14 is rotationally driven.

The support structure of the second planetary gear 26 of the planetary gear mechanism of the last stage, that is, the second stage, will be described with reference to FIGS.
FIG. 2 is a front view of one end side of the fixed casing 11, and FIG. 3 is a sectional view taken along line 3-3 in FIG. Fixed casing 11
Three trunnion bosses 25 are protrudingly provided at one end side at equal intervals of 120 ° on the circumference. A round portion 34 is formed at the base of the trunnion boss 25. However, the diameter of the circumscribed circle 35 of the three trunnion bosses 25 is
Outer periphery 3 of fixed casing 11 into which (see FIG. 1) is inserted
6 is almost equal to the diameter. Therefore, the round part 34
Of these, there is no round portion that interferes with the circumscribed circle 35.

Between the trunnion bosses 25 and on one end side of the fixed casing 11, three substantially triangular columns 28
Are protruded integrally from the fixed casing 11. The height H of the column 28 is near the center in the width direction of the second planetary gear 25 (see FIG. 1) supported by the trunnion boss 25.

FIG. 4 is a front view of the holder 24, and FIG. 5 is a sectional view taken along line 5-5 in FIG. The holder 24 is disk-shaped, and has three substantially triangular columns 27 integrally projecting toward one end of the fixed casing 11. Prop 2
7, three holes 37 into which the tips of the trunnion bosses 25 (see FIG. 3) fit are provided.

A second planetary gear 26 (see FIG. 1) is rotatably supported by a trunnion boss 25 shown in FIG. 3 via a needle bearing or the like. You. In this state, the columns 27, 2
The pin 31 (see FIG. 1) is fitted in the hole 38 between the holes 8, and the bolt hole 39 of the column 27 and the screw hole 4 of the column 28 are further inserted.
The bolt 30 (see FIG. 1) is screwed into the
28 is fixed in a state of contact with a mating surface 29. The bolt 30 and the pin 31 constitute fastening means for the columns 27 and 28.

The outermost peripheral portion of the trunnion boss 25 is almost in contact with the outer periphery 36 of the fixed casing 11, and a round portion 34 is formed at the root of the trunnion boss 25. With such a protruding structure of the trunnion boss 25, the stress concentration at the root portion is reduced and the bearing 13 (see FIG.
(See FIG. 3) can be reduced in diameter of the outer periphery 36 of the fixed casing 11 into which the fixed casing 11 is inserted. In addition, the fixed casing 11
The strut 28 integrally projecting from the holder and the strut 27 integrally projecting from the holder 24 abut on a mating surface 29, and the struts 27 and 28 are firmly fixed by bolts 30 via pins 31. . Therefore, the tip of the trunnion boss 25 is fitted into the hole 37 of the holder 24, and both ends are supported.

As shown in FIG. 1, a proper configuration of the columns 27 and 28 can reduce the bending stress at the root of the trunnion boss 25 and reduce the diameter of the trunnion boss 25. Further, by making the outermost peripheral portion of the trunnion boss 25 and the outer periphery 36 of the fixed casing 11 have substantially the same diameter, the outer diameters of the bearing 13 and the floating seal 32 inserted from one end side of the fixed casing 11 are suppressed, and 12, the outer diameter of the transmission 12 can be reduced to minimize the reduction gear 1 in the radial direction.

In FIG. 1, a tapered roller bearing is used as a bearing 13 for rotatably supporting a rotary casing 12 with respect to a fixed casing 11. This bearing 13
A nut 61 screwed into a screw portion 11b formed from the end face 41 of the fixed casing 11 toward the bearing 13 holds the fixed casing 11 while maintaining an appropriate tightening force.

The structure for preventing the rotation of the nut 61 will be described with reference to FIGS. 6 is a front view of the fixed casing 11 in which the nut 61 is screwed and the key plate 62 is attached, and FIG. 7 is a sectional view taken along line 7-7 of FIG.

As shown in FIG. 6, a number of pin holes 61a are provided on the side surface of the nut 61 at predetermined intervals. As shown in FIGS. 6 and 7, a cutout 65 is formed on the outer periphery of the support 28 of the fixed casing 11 in a circular arc shape and extends laterally from the end face 41. Key plate 6
2 has its side surface in contact with the side surface 65 a of the cutout portion 65 and is fixed to the side surface 65 a by two bolts 64. The two bolts 64 are provided with the left and right distribution distances changed with respect to the center line 11c. Further, the key plate 62 has two holes corresponding to the pin holes 61a of the nut 61.
The pin holes 62a are provided with the same left and right distribution distance of the center line 11c. The nut 61 is slightly rotated, and one of the two pin holes 62a is
It is possible to match with one pin hole 61a.

As shown in FIG. 7, the matching pin holes 61
Since the pin 63 is fitted into the a and 62a, the nut 61 is prevented from rotating by the key plate 62.

One column 28 on the side of the fixed casing 11
An arc-shaped notch 65 is provided in the vicinity of the center of the outer peripheral side surface. Since the stress distribution is small except for the end of the outer peripheral side surface of the column 28, the presence of the cutout 65 does not impair the role of the column 28 in relaxing the stress. Further, since the key plate 62 is located outside the end face 41 on one end side of the fixed casing 11, the fixed casing 11 is not elongated in the axial direction by the key plate 62.

In FIG. 1, the hydraulic motor 3 has a bottom 50 at one end inside a fixed casing 11 and an inner hole 52 closed at the other end by a lid 51. The output shaft 16 is arranged along the axis of the inner hole 52, and the output shaft 16 is rotatably held at one end by a bearing 53 provided on the lid body 51, and the other end side is provided with a bottom portion. In this configuration, the bearing 54 is rotatably held by a bearing 54 provided in the bearing 50. A cylinder block 56 in which a plurality of pistons 55 are slidably inserted is spline-connected to the output shaft 16 so as to be non-rotatably and slidably. A swash plate 58 swingably supported by steel balls 57 is provided on the bottom 50 side, and a cylinder 59 for tilting the swash plate 58 is provided at one end of the swash plate 58. The tip of a piston 55 is slidably abutted on the swash plate 58. When pressure oil is supplied to the cylinder block 56, the piston 55 is pushed out and the output shaft 16 is rotated by the reaction force. Pressure oil is supplied to and discharged from the cylinder block 56 via a counter balance valve (not shown) provided on the lid 51.

The present embodiment can be implemented with the following modifications. (1) The reduction mechanism 2 is a two-stage planetary gear mechanism.
Even with a three-stage planetary gear mechanism, the holding structure of the present embodiment can be applied to the last-stage planetary gear. (2) Further, even if the number of planetary gears revolving around the sun gear of the planetary gear mechanism is not limited to three but is four, the number of trunnion bosses and columns is set to four, and the holding structure of the present embodiment is provided. Can be adopted. (3) Although the trunnion boss and the column are formed integrally with the fixed casing, the trunnion boss or the column may be formed separately. (4) When the support is formed separately, the holder and the support may be integrally formed.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a sectional view of a hydraulic drive reduction device according to a second embodiment of the present invention.

8 differs from FIG. 1 in that the fixed casing 11 is provided on the outer peripheral side of the end face of the support column 27 of the holder 24.
A protrusion 77 is provided to protrude along the outer periphery of the support 28, and a pin 78 for preventing rotation is provided between the protrusion 77 and the nut 61 pressing the bearing 13.

The trunnion boss 75 is connected to the main body 75a.
Is a single product having shafts 75b on both sides of the shaft. A hole 76 is provided in the bottom 50 of the fixed casing 11 so that the holder 24
Is provided with a hole 37. One shaft 75b of the trunnion boss 75 is fitted in the hole 76, and the other shaft 75b of the trunnion boss 75 is fitted in the hole 37, whereby the trunnion boss 75 is supported at both ends. Other structures are the same as those described with reference to FIG. 1, and a detailed description thereof will be omitted.

As shown in FIGS. 9 and 10, the projecting portion 77 projecting from the holder 24 is integrally projected on the outer peripheral side of the column 27 of the holder 24. A hole 77 a for fitting the pin 78 is provided in the axial direction of the projection 77. A spring pin 78a for preventing the pin 78 from coming off is formed in the hole 77a.
Is fitted. As shown in FIG. 11, a pin hole 61a for fitting a pin 78 is provided on the side surface of the nut 61 more densely than in the case of FIG.

As shown in FIG. 12, the nut 61 is screwed into the screw portion 11b of the fixed casing 11, and the bearing 13 is pressed to a predetermined position. At this time, as shown in FIG.
The rotation of the nut 61 is stopped so that 1a is positioned directly above. Next, the holder 24 is pushed in with the positioning pin 31 as a reference. At this time, if the pin 78 is fitted in one of the holes 77a and 61a in advance, the pin 78 is fitted in the state shown in the drawing, and the rotation of the nut 61 is prevented.

Since the support 28 on the fixed casing 11 side is not provided with a notch, the strength of the support 28 is maintained. Also, since the key plate 62 of FIG. 1 is not used,
The number of parts is reduced, and the fixed casing 11 is not elongated in the axial direction.

[0041]

As described above, the traveling unit according to any one of the first to fifth aspects has the effect of reducing the size in the axial direction without increasing the outer diameter dimension, thereby enabling the overall size and weight to be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hydraulic drive reduction device according to a first embodiment of the present invention.

FIG. 2 is a front view of one end of a fixed casing.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a front view of the holder.

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a front view of a fixed casing to which a nut is screwed and a key plate is attached.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is a sectional view of a hydraulic drive reduction device according to a second embodiment of the present invention.

FIG. 9 is a front view of the holder.

FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;

FIG. 11 is a front view of one end of a fixed casing.

FIG. 12 is a sectional view taken along line 12-12 of FIG. 11;

FIG. 13 is a sectional view of a conventional traveling unit.

FIG. 14 is a sectional view taken along line 14-14 of FIG.

FIG. 15 is an enlarged side view of the key plate of FIG. 13;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling unit 2 Reduction mechanism 3 Hydraulic motor 11 Fixed casing 11a End face 12 Rotating casing 13 Bearing 15 Internal gear 16 Output shaft 17 First sun gear 20 First planetary gear 22 Second sun gear 24 Holder 25 Trunnion boss 26 Second planetary gear 27 Support 28 Support 61 Nut 62 Key plate 63 Pin 64 Bolt 65 Notch 77 Projection 78 Pin

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H070 AA01 BB04 BB06 CC34 CC37 DD91 DD92 DD94 DD96 3H084 AA08 AA16 AA45 BB26 BB30 CC62 CC63 3J027 FA36 FB10 GA01 GB02 GC24 GD02 GD08 GE12 GE25

Claims (5)

[Claims] 1. A fixed casing in which a hydraulic motor is disposed, and a rotary casing rotatably supported on the outer periphery of the fixed casing via a bearing inserted from one end of the fixed casing and having inner teeth on an inner peripheral side. A sun gear attached to an output shaft protruding from the hydraulic motor to the one end,
A planetary gear mechanism that is disposed between the sun gear and the internal teeth and that reduces the speed in a plurality of stages, and a planetary gear of the final stage that is disposed on the one end side of the fixed casing and meshes with the internal teeth so as to be rotatable. A supporting trunnion boss, and a holder into which the tip of the trunnion boss is inserted and attached to the fixed casing, wherein the bearing is axially positioned by a nut screwed onto the outer periphery of the fixed casing; A traveling unit provided with a key plate for stopping rotation, wherein the key plate is fixed at a position corresponding to an end surface of a fixed casing on which the trunnion boss is projected. 2. A column protruding from the fixed casing and a column protruding from the holder are fixed in an abutting manner, and the key plate is provided with a notch provided in the column on the fixed casing side. The traveling unit according to claim 1, wherein the traveling unit is fixed to the end surface in a state where the traveling unit is partially inserted in the traveling unit. 3. The traveling unit according to claim 1, wherein the trunnion boss is provided along an outer periphery of the fixed casing. 4. A fixed casing in which a hydraulic motor is disposed, and a rotatable casing rotatably supported on an outer periphery of the fixed casing via a bearing inserted from one end side thereof and having inner teeth on an inner peripheral side. A sun gear attached to an output shaft protruding from the hydraulic motor to the one end,
A planetary gear mechanism that is disposed between the sun gear and the internal teeth and that reduces the speed in a plurality of stages, and a planetary gear of the final stage that is disposed on the one end side of the fixed casing and meshes with the internal teeth so as to be rotatable. A traveling unit that supports a trunnion boss and a tip where the tip of the trunnion boss is inserted and is attached to the fixed casing, and the bearing is axially positioned by a nut screwed to the outer periphery of the fixed casing. A travel unit, wherein a pin for stopping rotation of the nut is provided between the nut and the holder. 5. A column protruding from the fixed casing and a column protruding from the holder are fixed in an abutting manner, and are projected from the holder along the outer periphery of the column on the fixed casing side. The traveling unit according to claim 4, wherein the pin is disposed between the protrusion and the nut.