JPH11229437A - Revolving device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a revolving device of a construction machine preventing not only deterioration of the energy efficiency but also play of gears resulting from backlash. SOLUTION: Two pairs of pinion gears 2G, 3G mounted in two pairs of hydraulic motors 2, 3 installed on an upper revolving body 1 are engaged with ring gears 5 installed in the lower traveling body 4. The driving of these hydraulic motors 2, 3 is controlled by two pairs of changeover valves 8, 9 having center bypasses 8a, 9a with restrictors so that mutually reverse torque is generated when the changing-over is less than a specified value, or in a low speed revolving command and the same directional torque is generated when the changing-over is more than a specified value, or in a high speed revolving command. As a result, backlash at the low speed revolving motion is prevented and an accurate positioning work can be done. Further, deterioration of the energy efficiency can be prevented at the high speed revolving movement.

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 in which the influence of backlash at a meshing portion between a pinion gear and a ring gear is considered.

[0002]

2. Description of the Related Art Generally, in a turning device of a construction machine such as a hydraulic excavator or a crane, a pinion gear is mounted on an output shaft of a hydraulic motor provided on an upper revolving unit, and the pinion gear meshes with a ring gear provided on a lower traveling unit. By rotating the pinion gear by driving the hydraulic motor, the pinion gear orbits along the ring gear, and the upper revolving unit rotates with respect to the lower traveling unit. At this time, a backlash is usually provided between the pinion gear and the ring gear to facilitate the meshing of the gears. However, if the backlash increases due to wear of the gear, rattling occurs in the gear of the turning device. Due to this rattling, for example, when the crane turns, swinging of the suspended load suspended on the hook occurs, and when the turning stops, the stop position for the rattling is shifted, and it becomes difficult to finely position the turning body.

As a solution to the problem caused by such backlash, for example, Japanese Patent Application Laid-Open No. 9-25647 discloses a turning device as shown in FIG.
According to this, a drive pinion gear 24 and a reaction force pinion gear 25 are mounted on two sets of hydraulic motors 20 and 21 having different capacities provided on the upper revolving unit via reduction gears 22 and 23, respectively. 25 meshes with a ring gear 26 of the lower traveling body. Then, the supply oil passage 2 from the supply oil passage 27 to the forward rotation side of the drive hydraulic motor 20 having a large capacity to the reverse rotation side of the reaction hydraulic motor 21 having a small capacity.
8, and a supply oil passage 30 from a supply oil passage 29 to the reverse rotation side of the drive hydraulic motor 20 to a forward rotation side of the reaction force hydraulic motor 21 is branched. In such a hydraulic device, the two hydraulic motors 20 and 21 generate torques opposite to each other, but since the driving torque of the driving hydraulic motor 20 is larger, the reaction force pinion gear 25 is in the same direction as the driving pinion gear 24. Rotated. At this time, the reaction force pinion gear 2
5 generates a reaction force, which can prevent rattling of the gear due to backlash. Note that 31
Is a hydraulic pump, and 32 is a control valve.

[0004]

However, in the turning device described above, the reaction force hydraulic motor 21 always generates a torque in the direction opposite to the turning direction, and this loss results in a loss, and energy efficiency during turning is reduced. Getting worse. Also, at the time of turning, the drive hydraulic motor 20 needs a larger drive torque to turn the upper turning body against the reverse torque of the reaction force hydraulic motor 21, and the hydraulic motor 20 becomes large.

An object of the present invention is to provide a turning device for a construction machine capable of preventing rattling of gears due to backlash without deteriorating energy efficiency or increasing the size of a motor.

[0006]

A description will be given with reference to the drawings showing an embodiment. (1) The invention of claim 1 is, as shown in FIGS.
First and second hydraulic motors 2, 3 provided on the upper-part turning body 1, pressure sources P (41, 42) for supplying pressure oil to the first and second hydraulic motors 2, 3, First and second pinion gears 2G, 3G mounted on output shafts 2a, 3a of the first and second hydraulic motors 2, 3, and a lower traveling body 4 meshed with the first and second pinion gears 2G, 3G;
The present invention is applied to a turning device of a construction machine provided with a ring gear 5 provided on a vehicle. The first and second hydraulic motors 2 and 3 generate torques in mutually opposite directions in the predetermined operation regions on the normal rotation side and the reverse rotation side including the time of neutral, and the forward rotation side exceeds the predetermined operation region. And the hydraulic source P (41, 41) so that the first and second hydraulic motors 2, 3 generate torque in the same direction in the operation region on the reverse rotation side.
The above-mentioned object is achieved by providing the motor drive control means 8, 9 (41a, 42a, 44) for controlling the pressure oil discharged from 42). (2) The first and second hydraulic motors 2 and 3 provided on the upper-part turning body 1 and the first and second hydraulic motors 2 are provided as shown in FIGS. , 3 and a hydraulic pump P for controlling the flow of discharge oil from the hydraulic pump P to control the first and second hydraulic motors 2, 3.
3, control valves 8 and 9 for driving and controlling, first and second pinion gears 2G and 3G mounted on output shafts 2a and 3a of the first and second hydraulic motors 2 and 3, respectively, The present invention is applied to a turning device of a construction machine having a ring gear 5 provided on the lower traveling body 4 and meshed with the second pinion gears 2G and 3G. Then, the control valves 8 and 9 are operated by a hydraulic fluid so that the first and second hydraulic motors 2 and 3 generate torques in opposite directions to each other in a predetermined operation region on the normal rotation side and the reverse rotation side including the neutral time. And the flow of the hydraulic oil is switched so that the first and second hydraulic motors 2 and 3 generate torques in the same direction in the forward rotation direction and the reverse rotation side operation regions exceeding the predetermined operation region. By doing so, the above-mentioned object is achieved. (3) The third aspect of the present invention is to control the control valves 8 and 9 by switching the flow of the hydraulic oil to the first hydraulic motor 2 by the first switching valve 8.
And a second switching valve 9 for switching the flow of the pressure oil to the second hydraulic motor 3. The first and second switching valves 8 and 9 have an integrated structure that is simultaneously switched and controlled. . (4) The invention according to claim 4 is characterized in that the first switching valve 8 and the second
The switching valve 9 has throttle-equipped center bypasses 8a and 9a at the neutral position where the inlet / outlet port communicates via the throttle.

[0007] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments are used to facilitate understanding of the present invention. However, the present invention is not limited to this.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a side view of a crane having a turning device of a construction machine according to an embodiment of the present invention. As shown in FIG. 1, an upper revolving unit 1 that is capable of turning via a turning wheel 18 is mounted above the lower traveling unit 4. Two sets of hydraulic motors 2 and 3 are provided in parallel with the upper swing body 1, and pinion gears 2 are provided on output shafts 2 a and 3 a of the hydraulic motors 2 and 3, respectively.
G and 3G are mounted, and these pinion gears 2G and 3G are meshed with a ring gear 5 fixed to the lower traveling body 4. The rotation of the hydraulic motors 2 and 3 causes the pinion gears 2G and 3 to rotate.
When G is driven, the pinion gears 2 </ b> G and 3 </ b> G rotate along the ring gear 5, and the upper rotating body 1 rotates with respect to the lower traveling body 4. In the first embodiment, the two sets of hydraulic motors 2 and 3 have the same capacity.

FIG. 2 is a hydraulic circuit diagram of the turning device of the construction machine according to the first embodiment. As shown in FIG.
The turning hydraulic pump P driven by the engine E is connected to one of the inlet ports of the first switching valve 8 and the second switching valve 9 via pipes 6 and 7, respectively. The other one of the inlet side ports of the first switching valve 8 and the second switching valve 9 is connected to the tank T via pipes 10 and 11. First
The switching valve 8 and the second switching valve 9 are four-port, three-position switching valves having center bypasses 8a, 9a with throttles, and are associated with the rightward operation of the swing lever 12 (hereinafter referred to as plus operation) ( The position is switched to the position (b) in accordance with the operation of the turning lever 12 to the left (hereinafter referred to as a minus operation). The outlet side port of the first switching valve 8 is connected to the first
And the outlet port of the second switching valve 9 is connected to the second hydraulic motor 3 via lines 15 and 16. The output shafts 2a of the hydraulic motors 2, 3
3a, the ring gear 5 of the undercarriage 4 as described above.
And pinion gears 2G and 3G that mesh with the gears.
Although not described in detail, a hydraulic brake device 17 for braking the output shaft 2a of the hydraulic motor 2 is provided.

Next, the operation of the turning device of the construction machine according to the first embodiment will be described. In the following description, clockwise (clockwise) rotation of the gears 2G, 3G, 5 is referred to as forward rotation, and left (counterclockwise) rotation is referred to as reverse rotation. (1) At neutral When the turning lever 12 is not operated, that is, at the time of neutral,
As shown in the hydraulic circuit diagram of FIG. 2, the pressure oil pumped from the hydraulic pump P passes through the pipelines 6 and 7 and the first switching valve 8
And the second switching valve 9, respectively, and the hydraulic motors 2,
Pressure oil corresponding to the size of the throttle of the center bypasses 8a and 9a of the switching valves 8 and 9 is supplied to the pipelines 13 and 15 on the upstream side of 3. Thereby, the clockwise drive torque acts on the first hydraulic motor 2 to try to rotate the pinion gear 2G in the forward direction, and the counterclockwise drive torque acts on the second hydraulic motor 3 to rotate the pinion gear 3G. Try to reverse it. In this case, the magnitudes of the driving torques of the hydraulic motors 8 and 9 are equal because the hydraulic motors 8 and 9 have the same capacity. As a result, the drive torques of the hydraulic motors 8 and 9 are balanced and the pinion gears 2G and 3G act to exert equal reaction forces to each other, so that gear rattling due to backlash can be prevented. The pressurized oil passes through the center bypasses 8a and 9a of the switching valves 8 and 9 and the tank T
Is returned to.

FIG. 3 is a diagram showing the relationship between the operation amount of the turning lever 12 and the turning torque. In FIG. 3, the origin 0
The right side corresponds to the plus operation of the turning lever 12, the left side corresponds to the minus operation of the turning lever 12, the upper side from the origin 0 corresponds to the turning torque in the forward direction, and the lower side corresponds to the turning torque in the reverse direction. The characteristics A and B correspond to the first motor 8 and the second motor
The upper revolving superstructure 1 shown by a broken line C is obtained by adding the revolving torques of the characteristics A and B to each other.
Is the turning torque. When the swing lever is in the neutral position, that is, FIG.
As described above, the first motor 8 and the second motor 9 are acted on by the drive torques having the same magnitude in the opposite directions to each other, as described above.
Turns to zero.

(2) Forward rotation When the turning lever 12 is positively operated in the direction of the arrow in FIG. 2, the switching valves 8, 9 are gradually switched from the neutral position to the position (b), Pressurized oil pipe 13,
15 is supplied. Thereby, the first hydraulic motor 2
, The torque on the forward rotation side of the second hydraulic motor 3 increases, and the torque on the reverse rotation side of the second hydraulic motor 3 decreases, so that the driving torque of the first hydraulic motor 2 is greater than the driving torque of the second hydraulic motor 3. The upper revolving superstructure 1 rotates forward. Here, when the turning lever 12 is operated between b and c in FIG. 3 in order to perform low-speed turning or the like, reverse torque acts on the second hydraulic motor 3 in this range, so that the pinion gear 3a is actuated. A force acts in a direction opposite to the turning direction. As a result, rattling due to backlash is prevented, and the upper-part turning body 1 rotates forward at a very small speed, thereby enabling a turning operation with high precision. If the turning lever 12 is operated to be larger than c in order to perform high-speed turning or the like, the driving torque in the forward direction acts on both the first hydraulic motor 2 and the second hydraulic motor 3, so that the The turning torque of the revolving superstructure 1 rapidly increases, and high-speed turning becomes possible.

(3) At the time of reverse rotation On the other hand, when the revolving lever 12 is operated in the minus direction from the neutral state in order to reverse the upper revolving superstructure 1, the switching valve 8,
9 is gradually switched from the neutral position to the position (a), and the pressure oil from the pump P is supplied to the pipelines 14 and 16. As a result, the forward torque of the first hydraulic motor 2 decreases, the reverse torque of the second hydraulic motor 3 increases, and the driving torque of the second hydraulic motor 3 becomes higher than the first torque. The driving torque of the hydraulic motor 1 becomes larger than that of the hydraulic motor 1, and the upper swing body 1 rotates in the reverse direction. When the operation amount of the swing lever 12 is between d and a in FIG. 3, the upper swing body 1 is rotated in the reverse direction in a state where the backlash is prevented, as in the case between b and c. However, after d, the upper swing body 1 is reversed by a large swing torque.

As described above, according to the first embodiment, the switching valves 8, 9 having the center bypasses 8a, 9a are provided between the hydraulic pump P and the two sets of hydraulic motors 2, 3, and the switching valves 8, 9 are provided. Hydraulic motors 2 and 3 at neutral and minute switching
Since reverse torques act on the gears, gear rattling due to backlash can be prevented. As a result, in a crane turning operation or the like, the positioning can be performed with high accuracy without load deflection, and the stop position does not shift due to the influence of wind or the like. Also,
By switching the switching valves 8 and 9 by a predetermined amount or more, the torques of the hydraulic motors 2 and 3 are made to act in the same direction, so that the small motor can easily be turned at high speed without deteriorating the energy efficiency. it can.

Second Embodiment Hereinafter, differences from the first embodiment will be mainly described. FIG. 4 is a hydraulic circuit diagram of a turning device of a construction machine according to the second embodiment, and the same parts as those in FIG. 2 are denoted by the same reference numerals. As shown in FIG. 4, the respective hydraulic motors 2 and 3 are connected to both tilt variable hydraulic pumps 41 and 42, respectively.
The regulators 41 a and 42 a for controlling the tilt angles of the hydraulic pumps 41 and 42 and the turning operation lever 43 having an operation amount detector 43 a such as a potentiometer are connected to a controller 44. The controller 44 previously stores drive torque characteristics A and B of the motors 2 and 3 corresponding to the operation amount of the operation lever 43 as shown in FIG. When the operation lever 43 is operated and a detection signal from the operation amount detector 43a is input to the controller 44, the pump 4 necessary to control the motors 2 and 3 to the characteristics shown in FIG.
The discharge amount and discharge direction of the first and second 42 are calculated, and a control signal is output to the regulators 41a and 42a. As a result, as in the first embodiment, gear rattling due to backlash can be prevented without deteriorating energy efficiency or increasing the size of the motor.

In the above embodiment, the characteristic shown in FIG. 3, which is the relationship between the operation amount of the turning lever 12 and the turning torque, is an example, and the setting of the spools of the switching valves 8 and 9 and the setting of the controller 44 are performed. 3 can be made to be arbitrary. Also, switching valves 8, 9
May be a pilot switching valve whose position is switched by the pilot pressure, and a pilot pressure corresponding to the operation amount of the turning lever 12 may be supplied to this switching valve. Further, the first switching valve 8 and the second switching valve 9 may have either an integral structure or a separate structure, and various shapes are conceivable.

[0017]

As described in detail above, according to the present invention, the drive torque of the hydraulic motor is controlled according to the size of the operation area of the operation lever and the like, and the operation area is controlled to be less than the predetermined area. The first and second hydraulic motors generate torques in opposite directions to each other, and when the operation area exceeds a predetermined area, generate torque in the same direction. Therefore, the operation area is small, for example, to prevent backlash during low-speed turning. And accurate positioning work can be performed, and the energy efficiency in a large operation area, for example, at the time of high-speed turning is not deteriorated. According to the third aspect of the present invention, since the switching valve for switching the flow of the hydraulic oil to the first and second hydraulic motors has an integral structure, the switching valve is switched by a single operation of the operator. Switching operability during work is improved. Further, according to the fourth aspect of the present invention, the switching valve having the center bypass with the throttle in which the inlet / outlet port is communicated via the throttle at the neutral position is provided, so that the gear rattling due to the backlash can be reduced with a simple configuration. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view of a crawler crane having a turning device according to an embodiment.

FIG. 2 is a hydraulic circuit diagram of the turning device of the construction machine according to the first embodiment.

FIG. 3 is a diagram showing a relationship between an operation amount of a turning lever and a turning torque of the turning device of the construction machine according to the embodiment.

FIG. 4 is a hydraulic circuit diagram of a turning device of a construction machine according to a second embodiment.

FIG. 5 is a hydraulic circuit diagram of a turning device of a construction machine according to the related art.

[Explanation of symbols]

 2 First hydraulic motor 3 Second hydraulic motor 2a, 3a Output shaft 2G, 3G Pinion gear 5 Ring gear 8 First switching valve 9 Second switching valve 8a, 9a Center bypass 41, 42 Double tilt variable hydraulic pump P Hydraulic pump

Claims (4)

[Claims] 1. A first and a second provided on an upper rotating body.
A hydraulic motor for supplying pressure oil to the first and second hydraulic motors; first and second pinion gears mounted on output shafts of the first and second hydraulic motors; In a turning device for a construction machine including a ring gear provided on a lower traveling body and meshed with first and second pinion gears, in a predetermined operation area on a normal rotation side and a reverse rotation side including a neutral state, The second hydraulic motor generates torques in opposite directions to each other, and generates torques in the same direction to the first and second hydraulic motors in the forward rotation side and reverse rotation side operation regions exceeding the predetermined operation region. A turning device for a construction machine, comprising: a motor drive control means for controlling pressure oil discharged from the hydraulic pressure source so as to cause the pressure oil to be discharged. 2. A first and a second provided on an upper rotating body.
A hydraulic motor, a hydraulic pump for supplying pressure oil to the first and second hydraulic motors, and a drive control of the first and second hydraulic motors by controlling a flow of discharge oil from the hydraulic pump. A control valve; first and second pinion gears mounted on output shafts of the first and second hydraulic motors; and a ring gear meshed with the first and second pinion gears and provided on the lower traveling body. In the turning device for a construction machine provided with the control valve, the control valve causes the first and second hydraulic motors to generate torques in opposite directions to each other in a predetermined operation area on a forward rotation side and a reverse rotation side including a neutral time. So that the first and second hydraulic motors generate torques in the same direction in the forward rotation direction and the reverse rotation side operation regions exceeding the predetermined operation region. Turning device for a construction machine is characterized in that so as to switch the flow of oil. 3. The control valve includes a first switching valve for switching a flow of pressure oil to the first hydraulic motor and the second switching valve.
3. The construction according to claim 2, further comprising a second switching valve for switching the flow of the pressure oil to the hydraulic motor, wherein the first and second switching valves have an integral structure that is simultaneously switched and controlled. Swivel of the machine. 4. The throttle valve according to claim 2, wherein the first switching valve and the second switching valve have a throttle-equipped center bypass in which a port is communicated via a throttle in a neutral position. The turning device for a construction machine according to claim 1.