JP2859168B2 - Swivel for construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning device for a construction machine, and more particularly to a backlash in a turning device in which a pinion gear and a ring gear are meshed.

[0002]

2. Description of the Related Art In a turning device of a construction machine such as a hydraulic excavator or a truck crane, a pinion gear is mounted on a hydraulic motor provided on an upper revolving unit, and a ring gear provided on a lower traveling unit is meshed with the pinion gear. When the pinion gear is rotated by driving the hydraulic motor, the pinion gear orbits along the ring gear, and the upper rotating body rotates with respect to the lower traveling body. In addition, a backlash is provided between the pinion gear and the ring gear to facilitate gear engagement.

[0003]

When the construction machine is used for a long period of time, the backlash increases due to the wear of each gear, and rattling occurs in the gear of the turning device. At that time, for example, when swinging with a suspended load on the hook of the crane and the swinging motion of the upper swing body occurs, load swing occurs, and even when the swinging is stopped, the stop position is shifted due to the play of the gear.

As a gear having a reduced backlash, a configuration described in Japanese Patent Application Laid-Open No. 4-371617 is known. This reduces the backlash by dividing the revolving gear into upper and lower parts, and fixing the revolving gear to the traveling body frame by slightly shifting the upper and lower pitches. However, the backlash cannot be set to 0 to make the rotation of the gear smooth, and it is difficult to eliminate the backlash of the gear due to a pitch error or wear of the gear.

Therefore, there arises a technical problem to be solved in order to eliminate the backlash of the gears without impairing the meshing characteristics of the gears of the turning device, to suppress the deflection of the load during turning and to improve the accuracy of the stop position. Therefore, an object of the present invention is to solve this problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in order to achieve the above object. A pinion gear is mounted on a hydraulic motor provided on an upper revolving unit, and a ring gear provided on a lower traveling unit and the pinion gear are provided. In the revolving device of the construction machine, the pinion gear is divided into upper and lower parts, and includes a driving pinion gear and a reaction force pinion gear, and the driving pinion gear is fitted to an output shaft of a hydraulic motor, The output shaft of the hydraulic motor is projected below the driving pinion gear, the reaction force pinion gear is freely rotatably fitted to the projected output shaft, and a rolling cylinder is fixed to a lower portion of the reaction force pinion gear. Furthermore,
A turning device for a construction machine, wherein an output shaft of the rolling cylinder is connected to an output shaft of the hydraulic motor, and a rotation direction of the output shaft of the hydraulic motor matches a rotation direction of the output shaft of the rolling cylinder; and The rolling cylinder is formed so that a rack is fixed to a piston and meshed with a pinion gear, an output shaft of the rolling cylinder is fitted to the pinion gear, and the piston is pressed toward a hydraulic port side by a spring. A two-position electromagnetic switching valve is interposed in the oil supply passage to the rolling cylinder, a hydraulic pump and a tank are connected to the inlet side of the electromagnetic switching valve, and the rotation direction of the output shaft of the hydraulic motor and the output of the rolling cylinder are output. An object of the present invention is to provide a turning device for a construction machine in which the electromagnetic switching valve is controlled so that the rotation directions of the shafts coincide with each other.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a mobile crane 11 in which a pinion gear 14 is mounted on a hydraulic motor 13 provided on an upper revolving unit 12, and a ring gear 16 fixed on a lower traveling unit 15 and a pinion gear 14 are meshed with each other. A turning device 17 is configured.

FIG. 2 shows a main part of the revolving device 17. The pinion gear 14 is divided vertically into a drive pinion gear 14a and a reaction force pinion gear 14b, and the drive pinion gear 14 is connected to an output shaft 18 of a hydraulic motor 13. 14a
And the output shaft 18 of the hydraulic motor is protruded below the driving pinion gear 14a, so that the bearings 19, 2
0, the hub 21 of the pinion gear 14b for reaction force is freely rotatably fitted.

A rolling cylinder 22 is fixed to a lower portion of the hub 21. In the rolling cylinder 22, a rack 24 is fixedly mounted on a piston 23 which moves in the horizontal direction. The spring 27 presses the piston 23 toward the hydraulic port 28 side.

Then, the output shaft 25 of the rolling cylinder protrudes above the rolling cylinder 22, the tip of the output shaft 25 of the rolling cylinder is fitted into the lower end of the output shaft 18 of the hydraulic motor, and the taper pin 29 is inserted. Then, both output shafts 18 and 25 are integrally connected. Also,
A swivel joint 31 is provided in the supply oil passage 30 to the rolling cylinder 22. The swivel joint 3
1 is installed at the center of the output shafts 18 and 25 and is mounted on a bracket 32 fixed to the upper swing body 12 so that pressure oil can be supplied even when the rolling cylinder 22 rotates. Is formed.

FIG. 3 shows a hydraulic circuit of the turning device. The pressure oil discharged from the first hydraulic pump 33 is guided to an oil passage 35 or 36 by a three-position four-port electromagnetic switching valve 34.
Counter balance valve 37 and stop / deceleration brake valve 38
Is supplied to the hydraulic motor 13.

The rotation of the hydraulic motor 13 is transmitted to an output shaft 18 of the hydraulic motor via a speed reducer 39. As described above, the driving pinion gear 1 is connected to the output shaft 18 of the hydraulic motor.
4a are integrally fitted and bearings 19, 20
A pinion gear 14b for reaction force is freely rotatably fitted via the hub 21. Reference numeral 40 denotes a brake cylinder.

On the other hand, the pressure oil discharged from the second hydraulic pump 41 is branched into two, one of which is supplied to the brake cylinder 40 through an electromagnetic switching valve 42 having two ports and three ports, and the other is supplied to the brake cylinder 40 at two ports. It is led to the supply oil passage 30 via the electromagnetic switching valve 43 of the port, and is supplied to the rolling cylinder 22 via the swivel joint 31.

Here, the electromagnetic switching valve 34 is moved to the left position 34
a, the solenoid of the electromagnetic switching valve 43 is turned off so as to be in the left position 43a, and when the electromagnetic switching valve 34 is switched to the right position 34b, the solenoid of the electromagnetic switching valve 43 is turned on. Control is performed so as to be at the right position 43b.

For example, when the electromagnetic switching valve 34 is set to the left position 34
a, the pressure oil of the first hydraulic pump 33 is supplied to the hydraulic motor 13 through the oil passage 35, the output shaft 18 of the hydraulic motor rotates forward through the speed reducer 39, and the driving pinion gear 14a also rotates forward. Turn over. At this time, the electromagnetic switching valve 43
Is in the left position 43a, the oil in the rolling cylinder 22 returns to the tank 44, and the spring 23
Is pressed toward the hydraulic port 28, the pinion gear 26 meshing with the rack 24 rotates forward, and the output shaft 25 of the rolling cylinder also attempts to rotate forward.

As described above, the output shaft 18 of the hydraulic motor and the output shaft 25 of the rolling cylinder are connected to each other, and the output shaft 18 of the hydraulic motor is connected to the speed reducer 39 and has a large rotational torque. , Both output shafts 18, 25
When the rotation directions of the rolling cylinders coincide with each other, the rolling cylinder 22 rotates in the direction opposite to the rotation direction of the output shaft 25 of the rolling cylinder. Then, the reaction force pinion gear 14b rotates integrally with the rolling cylinder 22 in the same direction.

Therefore, as shown in FIG. 4, if the driving pinion gear 14a rotates forward (in the direction of arrow A in FIG. 4),
Since the ring gear 16 is fixed, the upper swing body 12 swings in the arrow α direction. At this time, since the reaction pinion gear 14b rotates in the direction opposite to the driving pinion gear 14a, the state in which both pinion gears 14a and 14b are pressed together is maintained.

On the other hand, the electromagnetic switching valve 34 is moved to the right position 34b.
By switching to, the driving pinion gear 14a is inverted. At this time, the electromagnetic switching valve 43 is also switched to the right position 43b, so that the pressure oil of the second hydraulic pump 41 is supplied to the hydraulic port 28 of the rolling cylinder 22 and the spring 27
The piston 23 and the rack 24 move against the pressing of
The pinion gear 26 reverses and the output shaft 25 of the rolling cylinder also attempts to reverse.

Therefore, as shown in FIG. 5, if the driving pinion gear 14a is inverted (in the direction of arrow B in FIG. 5),
The upper swing body 12 swings in the arrow β direction. Again,
The pinion gear 14b for reaction force is the pinion gear 14a for driving.
The pinion gears 14
a and 14b hold the pressed state.

Thus, regardless of whether the drive pinion gear 14a is rotating forward, reverse, or stopped, the pinion gears 14a and 14b maintain the pressed state, so that the backlash with respect to the ring gear 16 is extremely small. As a result, the play of the gear is eliminated. Therefore, when turning with a suspended load on the hook (not shown) of the mobile crane 11 shown in FIG. 1, load swing does not occur because there is no backlash of the gears, and the stop position shifts when turning stops. Not even.

In order to smoothly engage the pinion gear 14 with the ring gear 16, a minimum backlash is required.
7 and the relief valve 45 provided in the second hydraulic pump 41 adjust the reaction force of the reaction pinion gear 14b with respect to the drive pinion gear 14a.

In this embodiment, a single-acting rotary cylinder is used. However, a plurality of oil passages are provided in a swivel joint to use a double-acting rotary cylinder or use a hydraulic motor. It can also take a reaction force.

Thus, the present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modifications.

[0024]

As described above, according to the present invention, the pinion gear meshing with the ring gear is divided into a driving pinion gear and a reaction pinion gear, and the reaction pinion gear is rotated in a direction opposite to the driving pinion gear. Accordingly, the state in which both pinion gears are pressed against each other is maintained, so that the backlash with respect to the ring gear becomes extremely small.

Therefore, the play of the gears can be eliminated without impairing the meshing characteristics of the gears of the turning device, the load swing during turning can be suppressed, and the accuracy of the stop position can be improved.

[Brief description of the drawings]

FIG. 1 is a partial side view of a mobile crane.

FIG. 2 is a side view of a main part of the turning device.

FIG. 3 is a hydraulic circuit diagram of the turning device.

FIG. 4 is a plan view of a main part showing an example of a meshing state of two pinion gears and a ring gear.

FIG. 5 is a plan view of a main part showing another example of a meshing state of two pinion gears and a ring gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Mobile crane 12 Upper revolving body 13 Hydraulic motor 14 Pinion gear 14a Drive pinion gear 14b Reaction force pinion gear 15 Lower traveling body 16 Ring gear 17 Revolving device 18 Output shaft (of a hydraulic motor) 22 Rolling cylinder 23 Piston 24 Rack 25 (Rolling cylinder) ) Output shaft 26 Pinion gear 27 Spring 28 Hydraulic port 30 Supply oil passage 41 Second hydraulic pump 43 Solenoid switching valve 44 Tank

Claims (2)

(57) [Claims] In a revolving device of a construction machine in which a pinion gear is mounted on a hydraulic motor provided on an upper revolving unit and a ring gear provided on a lower traveling unit meshes with the pinion gear, the pinion gear is divided into upper and lower parts. And a drive pinion gear and a reaction force pinion gear, and the drive pinion gear is fitted to an output shaft of a hydraulic motor,
The output shaft of the hydraulic motor is projected below the driving pinion gear, the reaction force pinion gear is freely rotatably fitted to the projected output shaft, and a rolling cylinder is fixed to a lower portion of the reaction force pinion gear. Further, the output shaft of the rolling cylinder and the output shaft of the hydraulic motor are connected so that the rotation direction of the output shaft of the hydraulic motor matches the rotation direction of the output shaft of the rolling cylinder. Swivel of the machine. 2. The rolling cylinder is formed such that a rack is fixedly mounted on a piston and meshes with a pinion gear, an output shaft of the rolling cylinder is fitted on the pinion gear, and the piston is pressed toward a hydraulic port by a spring. Further, a two-position electromagnetic switching valve is interposed in the oil supply path to the rolling cylinder, a hydraulic pump and a tank are connected to the inlet side of the electromagnetic switching valve, and the rotation direction of the output shaft of the hydraulic motor is changed. The turning device for a construction machine according to claim 1, wherein the electromagnetic switching valve is controlled such that a rotation direction of an output shaft of the rolling cylinder coincides with a rotation direction of the output shaft of the rolling cylinder.