JP2584366Y2 - Reduction gear - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as a hydraulic excavator or a hydraulic crane, and more particularly to a speed reducer such as a turning device thereof.

[0002]

2. Description of the Related Art A construction machine such as a hydraulic excavator or a hydraulic crane is provided with a turning device between a lower traveling structure and an upper revolving structure. A revolving hydraulic motor for the revolving unit, a one-stage or two-stage planetary reduction device for reducing the rotation of the revolving hydraulic motor, meshing with the revolving wheel, and revolving the upper revolving unit by the decelerating rotation from the deceleration device And a pinion. In the construction machine configured as described above, the lower traveling body is driven to travel, and excavation, loading, or crane work is performed by the working machine while the upper rotating body is swung by the swing device. Has become.

FIG. 2 shows a two-stage planetary speed reducer used in a conventional turning device. In the drawing, reference numeral 101 denotes a frame of an upper turning body, and 102 denotes a bolt 103 attached to the frame 101.
A housing fixed by Reference numeral 104 denotes a second-stage reduction ring gear located above the housing 102, and reference numeral 105 denotes an intermediate cover. The ring gear 104 is interposed between the housing 102 and the intermediate cover 105, and is fixed by bolts 106. Reference numeral 107 denotes a first stage reduction ring gear, which is an intermediate cover 105 and an upper cover 10.
8 and is fixed by bolts 109. A turning hydraulic motor 111 is provided on the upper cover 108, and the drive shaft 111a is connected to the upper cover 108.
The drive shaft 111a has a spline 11
1b is formed and spline-connected to the sun gear 113 of the first-stage reduction. The sun gear 113 is provided so as to be coaxial with the first-stage reduction ring gear 107, and is driven to rotate by a hydraulic motor 111.

A carrier 121 is provided coaxially with the first-stage reduction ring gear 107 and the sun gear 113, and has a lower portion provided with a gear 121a that meshes with the second-stage reduction sun gear 122. The planetary gear 114 is rotatably mounted on the first stage, and the planetary gear 114 meshes with the ring gear 107 and the sun gear 113. Therefore, when the sun gear 113 is rotationally driven by the turning hydraulic motor 111, the planetary gear 114
Will revolve around the sun gear 113 while rotating, and the carrier 121 to which the planetary gear 114 is mounted will rotate at the same speed as the revolving speed of the planetary gear 114. Here, the planetary gear 114 is reduced by the gear ratio with the sun gear 113 and further revolves at the gear ratio with the ring gear 107 to form a first-stage planetary reduction mechanism.

[0005] Next, as the second-stage reduction, the carrier 121 reduced by the first-stage planetary reduction mechanism is meshed with the teeth 122a of the second-stage reduction sun gear 122 by the gear 121a. 123 is a second stage reduction ring gear 104
And the sun gear 122 are coaxially arranged, and the lower part is the output shaft 13.
1 is a second-stage deceleration carrier connected to the spline 123a, that is, an output carrier. Reference numeral 124 denotes a second-stage reduction planetary gear rotatably attached to the output carrier 123 via a pin 125. The planetary gear 124 meshes with the ring gear 104 and the sun gear 122. Therefore, the sun gear 122 is connected to the carrier 12 of the first-stage reduction mechanism.
1, the second stage planetary gear 124
Will revolve around the sun gear 122 while rotating in the same manner as the first stage planetary gear described above.
Are rotated at the same speed as the revolving speed of the planetary gear 124. Here, the planetary gear 124 rotates at a reduced gear ratio with the sun gear 122 and revolves at a reduced gear ratio with the ring gear 104 to form a second-stage planetary reduction gear mechanism. .

The output shaft 131 has a lower portion supported by a bearing 133, an upper portion supported by a bearing 132, an upper end portion spline-coupled to an output carrier 123, and an upper end formed by a fixing plate 127 attached with a bolt 126. It is fixed to the output carrier 123. Reference numeral 131a denotes a pinion gear formed at the lower end of the output shaft 131, which meshes with a turning wheel 137 provided on a frame of a lower traveling body (not shown). Thus, the pinion gear 131
When a rotates the inner peripheral surface of the swing wheel 137, the upper swing body can be swung with respect to the lower traveling body.

[0007]

In the speed reducer constructed as described above, since the pinion gear 131a meshes with the turning wheel outside the bearing 133 supporting the output shaft 131, the reaction force (F ), The output shaft 131 is rotated by the reaction force (F).
Are tilted like 131c, so that the output carrier 123 is moved in the direction of the arrow (G). Further, the output carrier 123
At the same time, the sun gear 122 is also moved in the same direction, so that the carrier 121 meshing with the sun gear 122 is also moved in the (H) direction. Although the displacement increases as going upward, the sun gear 113 is connected to the output shaft 111a of the hydraulic motor.
The output shaft 131 is most likely to be affected by the bending of the output shaft 131 because the output shaft 131 is not moved because it is splined. As a result, the planetary gear 114 and the sun gear 113 or the planetary gear 1
There is a disadvantage that the contact of the tooth surface between the ring gear 14 and the ring gear 107 becomes very poor. Further, since the transmission elements of the power transmission system in the above-described conventional technology are connected in series, the resonance frequency of this system due to torsional vibration cannot be easily changed. The present invention aims to eliminate the above-mentioned disadvantages and to provide a reduction gear having a long life of the gear.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a speed reducer for rotating and outputting to an output shaft via a one-stage or two-stage planetary speed reducer connected to a rotary drive source. A buffer shaft, which is spline-coupled to each of the first carrier and the second sun gear, is interposed therebetween, and the rotational drive of the first carrier is transmitted to the second sun gear via the buffer shaft. Even if the first carrier is displaced due to the bending due to the reaction force of the above, the spline coupling between the first carrier and the second sun gear by the buffer shaft absorbs this displacement and causes a failure in each gear of the planetary reduction mechanism. The present invention is to provide a speed reducer that prevents the occurrence of.

[0009]

FIG. 1 shows an embodiment of the present invention.
This embodiment comprises a two-stage planetary gear mechanism as in the prior art shown in FIG. In FIG. 1, reference numeral 1 denotes a frame of the upper swing body, and 2 denotes a housing fixed to the frame 1 by bolts 3. Reference numeral 4 denotes a second-stage reduction ring gear located above the housing 2, and reference numeral 5 denotes an intermediate cover. The ring gear 4 is interposed between the housing 2 and the intermediate cover 5, and is fixed by bolts 6. Reference numeral 7 denotes a first-stage reduction ring gear interposed between the intermediate cover 5 and the upper cover 8 and fixed by bolts 9. Numeral 11 denotes a turning hydraulic motor standing upright on the upper cover 8, and a drive shaft 11 a is provided so as to protrude into the upper cover 8.
A spline 11b is formed in 1a, and is spline-connected to the sun gear 13 for first-stage reduction. Sun gear 1
Reference numeral 3 is provided so as to be coaxial with the first-stage reduction ring gear 7, and is driven to rotate by a hydraulic motor 11.

Reference numeral 21 denotes a carrier which is disposed coaxially with the first-stage reduction ring gear 7 and the sun gear 13, and has a lower portion which meshes with an upper portion of the buffer shaft 28;
1st stage reduction planetary gear rotatably mounted in 5,
The planet gear 14 meshes with the ring gear 7 and the sun gear 13. Therefore, when the sun gear 13 is driven to rotate by the turning motor 11, the planetary gear 14 revolves around the sun gear 13 while rotating, and the carrier 21 on which the planetary gear 14 is mounted becomes It rotates at the same speed as the revolution speed. Here, the planetary gear 14 is reduced by the ratio of the number of teeth with the sun gear 13 and further revolves at the ratio of the number of teeth with the ring gear 7, thereby constituting a first-stage planetary reduction mechanism.

The rotation output from the carrier 21 reduced by the first-stage planetary reduction mechanism is transmitted to the second-stage reduced sun gear 22 by the buffer shaft 28. The lower portion of the buffer shaft 28 meshes with a part of the teeth 22a of the sun gear 22 and the teeth 28a of the buffer shaft 28. 23 is disposed coaxially with the second stage reduction ring gear 4 and the sun gear 22;
The lower portion is connected to the output shaft 31 by a spline 23a.
The carrier is a step-down carrier, that is, an output carrier. Reference numeral 24 denotes a second-stage reduction planetary gear rotatably attached to the output carrier 23 via a pin 25. The planetary gear 24 meshes with the ring gear 4 and the sun gear 22. Accordingly, when the sun gear 22 is driven to rotate at reduced speed by the carrier 21 of the first-stage reduction mechanism via the buffer shaft 28, the second-stage planetary gear 24 rotates similarly to the first-stage planetary gear while rotating the sun gear 22. The planetary gear 24 revolves around the planetary gear 24 and the output carrier 23 is mounted on the planetary gear 2.
The rotation speed is reduced at the same speed as the revolution speed of No. 4. Here, the planetary gear 24 rotates at a reduced gear ratio with respect to the sun gear 22 and revolves, and further revolves at a reduced gear ratio with the ring gear to form a second-stage planetary reduction gear mechanism.

The output shaft 31 is rotatably supported by the housing 2 via a bearing 32 at an upper portion and a bearing 33 at a lower portion. Further, the upper end of the output shaft is connected to a bolt 2 via a fixing plate 27.
6, the output carrier 23 and the output shaft 3 spline-coupled.
1 is fixed. Reference numeral 31a denotes a pinion gear formed at the lower end of the output shaft 31, which meshes with a turning wheel provided on a frame of a lower traveling body (not shown). In this manner, the pinion gear 31a rotates the inner peripheral surface of the revolving wheel 37, whereby the upper revolving unit can be turned with respect to the lower traveling unit.

The speed reducer according to the present invention is configured as described above, and its operation will be described. The point that the rotation of the drive shaft 11a of the turning hydraulic motor 11 is transmitted to the output shaft 31 via the two-stage planetary reduction gear mechanism is not particularly different from that of the prior art. However, the pinion gear 31a
Is engaged with the turning wheel outside the bearing 33 that supports the output shaft 31, and receives a reaction force (F) in the direction of the arrow, and the output shaft tilts by the deflection of the bearing due to the reaction force (F).
The movement of the position of the output carrier 23 due to the influence is as described in the problem to be solved by the present invention. However, due to the presence of the buffer shaft 28, the output carrier 2
The movement of the position 3 is absorbed by the spline-coupled buffer shaft 28 and has little effect on the carrier 21 of the first-stage reduction mechanism. Therefore, the planetary gear 14 can maintain the normal meshing with the sun gear 13 and the ring gear 7, and can maintain the normal state of the contact with the tooth surface. Although the above embodiment has been described with reference to the case where the present invention is applied to a turning device, the present invention may be applied to a traveling speed reduction device for a lower traveling body.

[0014]

As described above, the speed reducer according to the present invention absorbs the radial load displacement received by the output shaft, and regardless of the displacement of the carrier of the second speed reducer, the first speed reducer. The rotational force of the sun gear is evenly transmitted to each planetary gear without causing a problem such as one-sided engagement in the meshing of the sun gear, the planetary gear, and the ring gear, thereby extending the life of the gear. Since the transmission elements are connected in series, the resonance frequency of this vibration system is affected by the element with the smallest stiffness, but it can be easily changed by changing the stiffness of the buffer shaft according to the present invention. it can. Therefore, since the generation of vibration and noise can be prevented, its practical value is extremely high.

[Brief description of the drawings]

FIG. 1 is a sectional view of a speed reducer showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a speed reducer showing one example of the related art.

[Explanation of symbols]

 Reference Signs List 1 frame 2 housing 4 ring gear 5 intermediate cover 7 ring gear 8 upper cover 11 hydraulic motor 11a drive shaft 11b spline 13 sun gear 14 planetary gear 15 pin 21 carrier 21a spline 22 sun gear 22a teeth 23 output carrier 24 planetary gear 25 pin 27 fixed plate 28 buffer Shaft 28a Tooth 32 Bearing 31 Output shaft 33 Bearing 31a Pinion gear 37 Slewing ring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02F 9/12 F16H 1/28

Claims (1)

(57) [Scope of request for utility model registration] A first carrier and a second sun gear each provided with a buffer shaft which is spline-coupled to a first carrier and a second sun gear; A speed reducer, wherein the rotational output of the first carrier is transmitted to the second sun gear via a buffer shaft.