JP2002013598A - Reduction gear in excavator and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a carrier and an output shaft in a planet gear type speed reduction mechanism as a separate member to be combined together, to make possible a independent replacement and so on thereof, and to reduce costs for dies and workings for manufacture. SOLUTION: In the reduction gear for an excavator and the like which transmits a rotation of a drive shaft 7 connected to a driving motor to an output shaft 34 through the planet gear type speed reduction mechanism 24 comprising a sun gear 30 connected to the drive shaft 7, a ring gear 5 therearound, and a plurality of planetary gear 33 engaged autorotatably and revolvably with the sun gear and the ring gear, the upper end of the output shaft 34 is fastened detachably by fixing means 36, 39 to a bottom end of the carrier 31 which holds each of the planetary gear 33 autorotatably and revolvably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear type reduction gear mounted on an excavator such as an earth drill.

[0002]

2. Description of the Related Art For example, among earth drills used for a method of constructing a reinforced concrete foundation pile by piercing the ground, there is an earth drill provided with a planetary gear type reduction gear. In this reduction gear transmission, a sun gear is linked to a drive shaft rotated by a hydraulic motor or the like, and a plurality (usually three) of planetary gears meshed with the sun gear are meshed with a ring gear so as to be able to rotate and revolve. By transmitting the rotation of the carrier holding the rotation to the output shaft, the rotation of the drive shaft is reduced, so that a large excavation force can be obtained.

Heretofore, the output shaft of the speed reducer has been formed integrally with a carrier holding a planetary gear by casting or cutting a round bar.

[0004]

As described above, when the output shaft and the carrier are integrally formed,
For example, when one of them becomes worn or the like and needs to be replaced, it must be replaced with another one which is still usable, which is uneconomical.

[0005] Further, since the material of the carrier and the output shaft cannot be selected, for example, if the output shaft is made of a material having excellent mechanical strength and abrasion resistance, a carrier which does not need much mechanical strength is required. The side is over-quality and costs increase. Conversely, if the carrier is made of inexpensive cast iron or the like, the durability of the output shaft may be impaired.

Further, when the output shaft and the carrier are integrally formed by casting or shaving, a mold having a large diameter and a complicated shape is required, which increases the cost and requires a lot of time for machining. There is also a problem that productivity does not increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the carrier and the output shaft are formed separately from each other by using a material suitable for the carrier and are connected to each other so that the exchange and the like can be performed separately. It is an object of the present invention to provide a speed reducer for an excavator or the like which can be manufactured at a low cost by reducing a mold cost and a processing cost required for the manufacture.

[0008]

According to the present invention, the above-mentioned problem is solved as follows. (1) a sun gear linked to the drive shaft, a ring gear surrounding the sun gear, and a plurality of planetary gears meshed with the sun gear and the ring gear so as to be able to rotate and revolve. In a reduction gear in an excavator or the like transmitting to an output shaft via a planetary gear type reduction mechanism comprising: a lower end of a carrier that holds each planetary gear so that it can rotate and revolve, an upper end of the output shaft is fixed by a fixing means. Removably fixed.

(2) In the above item (1), the fixing means
Attachment pins protruding at any of a plurality of locations on the opposing surfaces of the enlarged diameter flange portion and the carrier at the upper end of the output shaft, and screw holes to be drilled in the attachment pins, from the carrier or the enlarged diameter flange side. It consists of bolts that are screwed together.

(3) In the above item (1) or (2), the lower end of the support shaft that rotatably holds each planetary gear is press-fitted into the enlarged diameter flange at the upper end of the output shaft.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a reduction gear transmission of the present invention applied to an earth drill. A housing (1) has a substantially cylindrical gear case (2) at a central portion and a clutch case (3) fixed to an upper end thereof. An output case 4 is also fixed to the lower end, and the lower end of the gear case 2 also serves as a ring gear 5 of a second reduction mechanism 24 described later.

A drive shaft housed in the center of a guide cylinder (6) connected to the upper ends of the gear case (2) and the clutch case (3).
(7) The upper end is a partition (6a) at the lower end of the guide cylinder (6).
Thus, it is rotatably supported via a bearing (8).

The drive shaft (7) has a spline (9) at its upper end.
The joint at the lower end of the rotary shaft (10) of the hydraulic motor (not shown)
(10a) is rotated by meshing. A drive gear (11) is formed at an intermediate portion of the drive shaft (7) located in the clutch case (3), and a drive ring (12) is engaged with the drive gear (11).

A drive member (13) having a bottomed cylindrical shape is rotatably mounted on a drive shaft (7) below the drive gear (11) so as to surround the drive ring (12). The outer peripheral surface of the intermediate portion is supported by a bearing (14) fitted in a through hole in the upper wall (2a) of the gear case (2).

In an annular space between the inner peripheral surface of the upper end of the transmission member (13) and the outer peripheral surface of the drive ring (12), a pressure plate and a clutch disk (both not shown) alternately stacked are provided. The high-speed multi-plate clutch (15) relatively rotates the outer peripheral surface of the pressure plate on the inner peripheral surface of the transmission member (13) and the inner peripheral surface of the clutch disc on the outer peripheral surface of the drive ring (12). It is housed in such a manner as to be disengageable and movably engaged in the axial direction.

A transmission member below the multi-plate clutch (15)
In (13), a hydraulic piston (16) is housed, and by controlling the pressure of the pressure chamber supplied to the oil chamber below, the rotation of the drive ring (12) is intermittently connected to the transmission member (13). Is done.

Outside the transmission member (13), a low-speed multi-plate clutch (17) is housed in the clutch case (3), and a plurality of locations on the outer peripheral end of each pressure plate (18) are: A fixed pin (19) press-fitted between the upper surface of the gear case (2) and the facing surface of the clutch case (3) is movably engaged in the axial direction, and is prevented from rotating around the axis.

The inner peripheral surface of the clutch disk (20) alternately inserted between the upper and lower pressure plates (18) is relatively non-rotatable and axially movable on the outer peripheral surface of the transmission member (13). Is engaged.

A plurality of compression coil springs (return springs) (21) are provided at equal intervals in the circumferential direction between the lower surface of the outer peripheral portion of the uppermost pressure plate (18) and the upper surface of the gear case (2). It is interposed.

(22) The uppermost pressure plate (18)
By controlling the pressure of the pressure oil supplied to the oil chamber above it with a hydraulic piston that presses the upper surface of the transmission member (1
3) Restrict or allow rotation. Gear case (2)
Inside, a first and second two-stage planetary gear type reduction mechanism including a first reduction mechanism (23) and a second reduction mechanism (24) are accommodated.

The first reduction mechanism (23) is composed of a carrier (25) rotating around a drive shaft (7), and three vertical shafts (26) on the carrier (25). Three planetary gears (27) rotatably held at equal intervals in the direction, and a sun gear (28) integrally formed at the lower end of the drive shaft (7) and meshing with the inner end side of each planetary gear (27). ) And carrier (2
The planetary gears (27) are rotatably provided so as to surround the planetary gears (27), and the outer ends of the planetary gears (27) mesh with ring gears (29) .The upper end of the ring gear (29) is serrated at the lower end of the transmission member (13). Are combined.

The second speed reduction mechanism (24) includes a sun gear (30) provided coaxially below the drive shaft (7), a carrier (31) rotating about the sun gear (30), and a carrier (31). Three
In (1), it is rotatably held at equal intervals in the circumferential direction by three support shafts (32) pointing in the vertical direction, and the inner end is a sun gear (3).
(0) three planetary gears (33) meshed with the lower end,
The outer end of each planetary gear (33) is in mesh with the above-described ring gear (5).

The upper teeth of the sun gear (30) mesh with internal teeth (25a) formed on the lower inner peripheral surface of the carrier (25) in the first reduction mechanism (23).

As shown in FIGS. 2 and 3, the carrier (31) has a top wall (31b) having a through hole (31a) through which a sun gear (30) flows, and a circumferential wall extending from the outer peripheral edge thereof. And three legs (31c) that hang down at equal intervals in the direction. A planetary gear (33) is held by a support shaft (32) in a gap between the legs (31c). Omitted).

The carrier (31) is integrally formed of cast iron.

At the lower end of each leg (31c) of the carrier (31),
A mounting pin (34) in which an enlarged-diameter flange (34a) at the upper end of the output shaft (34) is press-fitted from below by a cold fit or the like into three mounting holes (35) drilled at equal intervals. The protrusion at the upper end of (36) is press-fitted into the upward concave hole (37) at the bottom of each leg (31c), and the screw hole (38) is formed in the mounting pin (36).
The bolt (39) inserted from the top wall (31b) side of the carrier (31) is screwed and firmly fixed.

Spindles holding each planetary gear (33)
The lower end of (32) is press-fitted into a bottomed hole (40) formed in the enlarged diameter flange (34a), and a strong relative rotation between the carrier (31) and the output shaft (34) is stopped. Is

The output shaft (34) is made of, for example, chromium molybdenum steel or the like having excellent mechanical strength, and its surface is subjected to a hardening treatment such as induction hardening.

The intermediate portion of the output shaft (34) is rotatably supported by a bearing (41) fitted to the inner surface of the opening of the output case (4).

A rotary shaft (both not shown) of the drill is engaged with a spline (42) formed on the outer peripheral surface of the lower end of the output shaft (34).

In the speed reducer having such a configuration, when the rotation of the rotary shaft (10) is reduced and taken out from the output shaft (34),
The low-speed multi-plate clutch (17) is operated, and the high-speed multi-plate clutch (15) is set free.

Then, since the rotation of the transmission member (13) and the ring gear (29) of the first reduction mechanism (23) meshing with the transmission member (13) are restricted, the rotation of the drive shaft (7) is restricted by the rotation of the sun gear (28). ) Is transmitted to each planetary gear (27) of the first reduction mechanism (23), and each planetary gear (27) rotates while rotating in a state in mesh with the sun gear (28) and the ring gear (29).
Revolves with (25). Thereby, the rotation of the drive shaft (7) is transmitted to the carrier (25) after being reduced by the first stage, and this rotation is further transmitted to the sun gear (30) of the second reduction mechanism (24).

When the sun gear (30) rotates, each planetary gear (33) meshing with the sun gear (30) revolves with the carrier (31) while rotating, and the output fixed to the carrier (31). The shaft (34) is rotated at a large reduction ratio.

Thus, the excavation drill attached to the output shaft (34) is rotated with a large torque.

On the other hand, when the speed of the output shaft (34) is set to be higher than the above by setting the reduction ratio to be small, the high-speed multi-plate clutch (1
Operate 5) to release the low-speed multi-plate clutch (17). Then, the drive shaft (7) and the transmission member (13) rotate integrally, and each planetary gear (27) revolves only to rotate the carrier (25).

Accordingly, there is no deceleration effect by the first reduction mechanism (23), and the rotation of the drive shaft (7) is transmitted to the sun gear (30) of the second reduction mechanism (24) via the carrier (25). As described above, the output shaft (34) is actuated by the speed reduction action of the second speed reduction mechanism (24).
Are rotated with a smaller reduction ratio than the above.
Thus, when the soil is discharged from the drill hole, the number of rotations of the drill can be increased, and the soil attached to the drill can be easily dropped.

As described above, in the speed reducer of the above embodiment, the carrier (31) and the output shaft (34) of the second speed reducer (24) are formed separately, and they are attached to the mounting pin ( 36) and bolts (39) for detachable connection, so when replacing one of them due to wear or the like, it is necessary to replace it with the other that is still usable, as in the case of the conventional integrated structure Not economical.

Further, since the material of the carrier (31) and the material of the output shaft (34) can be separately selected to be suitable for the material, one of them may be excessive in quality or deteriorate in durability or the like. Is gone.

Furthermore, unlike the related art, there is no need to produce a large-sized mold or to form the whole by shaving, so that the mold cost and machining cost are reduced.

The present invention is, of course, applicable to a speed reducer having a single speed reduction mechanism without a multi-plate clutch, in addition to a speed reduction mechanism having two upper and lower stages as described above.

[0041]

According to the first aspect of the present invention, since the carrier and the output shaft are formed separately, when one of them is replaced due to abrasion or the like, it is replaced with the other which is still usable. No need, it is economical. In addition, since the material of the carrier and the material of the output shaft can be separately selected to be suitable for the material, there is no danger that one of them becomes excessive quality or the durability is reduced. Furthermore, unlike conventional integrated molded products, there is no need to manufacture large molding dies or form the whole by shaving, which reduces the cost of the mold and processing costs, and reduces the cost of reduction gears. Becomes

According to the second aspect of the present invention, the coupling strength between the carrier and the output shaft can be increased.

According to the third aspect of the invention, even if the reduction ratio of the output shaft is large and a large excavation torque acts on it,
There is no danger of the carrier and the output shaft rotating relative to each other or rattling.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional front view showing an embodiment of the present invention.

FIG. 2 is a perspective view of the coupling state between the carrier and the output shaft as viewed from above.

FIG. 3 is a perspective view of the coupling state between the carrier and the output shaft as viewed from below.

[Explanation of symbols]

 (1) Housing (2) Gear case (2a) Upper wall (3) Clutch case (4) Output case (5) Ring gear (6) Guide cylinder (7) Drive shaft (8) Bearing (9) Spline (10) Rotary shaft (10a) Joint (11) Drive gear (12) Drive ring (13) Transmission member (14) Bearing (15) (17) Multi-plate clutch (16) Hydraulic piston (18) Pressure plate (19) Fixing pin (20) Clutch disc (21) Compression coil spring (22) Hydraulic piston (23) First reduction mechanism (24) Second reduction mechanism (25) (31) Carrier (26) (32) Support shaft (27) (33) Planetary gear (28) (30) Sun gear (29) Ring gear (34) Output shaft (35) Mounting hole (36) Mounting pin (37) Concave hole (38) Female screw hole (39) Bolt (40) Bottom Hole (41) Bearing (42) Spline

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16H 57/08 F16H 57/08 F term (reference) 2D029 AA01 3J027 FB10 GA01 GB03 GC13 GC23 GD03 GD13 GE23 3J028 EA07 EA24 EA28 EB04 EB63 FA59 FB03 FC02 FC12 FC24 FC63 FD01 FD23 GA12 HA15 HA32 3J063 AA15 AB12 AB53 AC03 BB11 BB48 CA01 CB04 CB06 CB17 CD17 CD53 XA05

Claims (3)

[Claims] A rotation of a driving shaft connected to a driving motor is controlled by a sun gear linked to the driving shaft, a ring gear surrounding the sun gear, and a plurality of gears meshed with the sun gear and the ring gear so as to be able to rotate and revolve. In a speed reducer in an excavator or the like that transmits an output shaft via a planetary gear type reduction mechanism including a planetary gear, an upper end of the output shaft is fixed to a lower end of a carrier that holds each of the planetary gears so that the planetary gear can rotate and revolve. A speed reducer for an excavator or the like, which is detachably fixed by means. 2. A fixing device comprising: a mounting pin protruding at any one of a plurality of locations on an opposing surface of an enlarged-diameter flange at an upper end of an output shaft and a carrier; and a screw hole formed in the mounting pin. 2. The reduction gear transmission for an excavator according to claim 1, wherein said reduction gear comprises a carrier, or a bolt screwed from a side of said enlarged diameter flange. 3. The speed reducer for an excavator according to claim 1, wherein a lower end of the support shaft that rotatably holds each planetary gear is press-fitted into an enlarged-diameter flange at an upper end of the output shaft.