JPH0730963Y2 - 2-motor swing circuit - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hydraulic circuit for turning of an upper turning construction machine equipped with two turning motors.

2. Description of the Related Art FIG. 3 is a side view of a large hydraulic excavator. In the figure, 1 is an upper revolving structure, 2 is a lower traveling structure, and 3 is a revolving bearing.
Reference numeral 4 denotes a work attachment mounted on the front part of the upper swing body 1. FIG. 4 is a cross-sectional side view of essential parts showing a turning device of a large hydraulic excavator. In the figure, 3 is a slewing bearing, 5 is an inner ring of the slewing bearing 3, 6 is an internal gear of the inner ring 5,
7 is an outer ring, 8 is a rolling element, 9 is a bottom plate of the upper revolving unit 1, and 10
Is a top plate of the lower traveling body 2, 11 and 11 'are turning motors, and 12 and 12' are pinions of the turning motors 11 and 11 ', respectively. In the turning device shown in FIG. 4, the inner ring 5 having the internal gear 6 is fixed to the upper plate 10 of the lower traveling body 2, and the outer ring 7 is fixed to the lower plate 9 of the upper rotating body 1 and the outer ring 7 is fixed.
A plurality of rolling elements 8 are fitted on the same circumference between the inner ring 5 and the inner ring 5. On the other hand, two swivel motors 11, 11 'pinions 12, 12' installed on the upper swivel body 1 are meshed with the internal gear 6. The upper revolving superstructure 1 is caused to revolve by rotating both revolving motors 11 and 11 'in the same direction.

FIG. 5 is a conventional two-motor swing circuit diagram. In the figure, 11 and 11 'are swing motors, 13 is a swing valve, and 1
4 is a remote control valve for turning, 15 and 16 are main pumps respectively,
17 is a pilot pump. When the operation lever 18 of the remote control valve 14 is operated from the neutral position to the a position or the b position,
The pilot pressure from the pilot pump 17 passes through the oil passage 19, the pilot valve 20 or 21, the oil passage 22 or 23, and then the swing valve.
It acts on the pilot pressure receiving portion 24 or 25 of 13. Swivel valve
Since 13 switches to C position or D position, swing motor 1
Both 1,11 'perform normal rotation or reverse rotation in the same direction.

Problems to be Solved by the Invention In a large hydraulic excavator or the like, two relatively medium-sized swing motors are installed to perform the swing operation of the upper swing body. On the other hand, the outer ring of the slewing bearing is rotatably operated with respect to the inner ring via the rolling elements, and thus there is a slight clearance between the rolling grooves of the outer ring and the inner ring and the rolling elements. Further, there is a considerable backlash between the meshing teeth of the internal gear of the inner ring and the turning pinion. As a result, the tip of the work attachment mounted on the hydraulic excavator has a rattling width of several tens of wear. Therefore, it is difficult to position the tip of the work attachment or perform fine movement operation. When excavating with a work attachment, for example, a backhoe bucket, without rattling the upper revolving structure of the hydraulic excavator, rattling due to the above gaps and backlash propagates to the driver's cab, making the ride uncomfortable and uncomfortable. there were.

An object of the present invention is to improve the above-mentioned problems and to provide a two-motor turning circuit that reduces rattling between meshing teeth of an internal gear of an inner ring and a turning pinion.

Means for solving the problems a. A slewing bearing having an internal gear is provided between the upper slewing body and the lower traveling body, and two slewing motors are installed in the upper slewing body, and the pinion for the slewing motor and the internal gear are respectively provided. When the swivel valves that engage with each other and control the rotation of the two swivel motors are returned to the neutral position, the pump pressure is applied to the forward rotation side flow path of one of the two swivel motors.
In the two-motor swing circuit of the construction machine, which is introduced into the reverse flow path of the other swing motor, An oil passage for working pressure oil is provided at the neutral position of the swivel valve, and the inlet of the oil passage for working pressure oil communicates with the oil passage on the discharge side of the main pump, and the outlet is on the forward rotation oil passage of one of the swing motors and the other Communicate so as to communicate with the oil passage on the reverse side of the swing motor of c. In addition, a pilot switching valve is provided in the oil passage that connects the main pump and the swing valve, and the pilot switching valve is placed in the tank communication oil passage position at the neutral position of the swing remote control valve for swing valve switching control, and at the swing remote control. It is set so that it can be interlocked with the open oil passage position when the valve is in the operating position. Further, the oil passage on the discharge side of the pilot pump and the inlet of the oil passage for the working pressure oil are made to communicate with each other via a chuck valve for preventing backflow of the pressure oil to the pilot pump side.

Action a. When the operating lever of the turning remote control valve is operated in either direction from the neutral position, the pilot switching valve and the turning valve are switched. The pressure oil discharged from the main pump is supplied to the two swing motors through the hydraulic oil passage position of the pilot switching valve and the swing valve. Therefore, the two turning motors perform normal rotation or reverse rotation in the same direction.

B. When the operating lever of the remote control valve for turning is returned to the neutral position, the pilot switching valve moves to the tank communication oil passage position.
Also, the swing valve returns to the neutral position. The low-pressure hydraulic oil from the pilot pump acts as a rotational force that causes the two rotary motors to act in mutually opposite rotational directions via the oil passage for the working hydraulic oil in the neutral position of the swirling valve.

C. When the revolving structure of the revolving structure is stopped as described in the above item (b), the rotational forces in opposite directions act on the two revolving motors by the low pressure oil, so that the internal gear of the inner ring and the revolving pinion are rotated. There is no rattling between the mating teeth.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a two-motor turning circuit diagram according to the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art. 26 is a swing valve, 27 is a pilot switching valve, 28 is a shuttle valve, and 29 is a check valve.

Next, the configuration of the two-motor turning circuit of the present invention will be described with reference to FIG. In the present invention, the working pressure oil passage 30 is provided at the neutral position of the turning valve 26 for controlling the rotation of the two turning motors 11 and 11 ′, and the working pressure oil passage 30 has an inlet on the discharge side of the main pump 15. The passage is connected to the oil passage 32, and the outlet is connected to the forward rotation side flow path connected to the port (L) of one of the turning motors 11 and the reverse rotation side flow path connected to the port (E) of the other turning motor 11 '. A pilot switching valve 27 in an oil passage (32, 33-34) communicating with the main pump 15 and the swing valve 26.
The discharge oil from the main pump 15 can be switched to the tank communication oil passage position of the pilot switching valve 27 when the swivel valve 26 is in the neutral position, and to the open oil passage position when the swivel remote control valve 14 is in the operating position. Further, the discharge side oil passage 35 of the pilot pump 17 and the inlet of the working pressure oil passage 30 are connected to each other via a check valve 29 for preventing backflow of pressure oil to the pilot pump 17 side.

Next, the function and function of the two-motor turning circuit according to the present invention will be described. When the operation lever 18 of the turning remote control valve 14 is operated to the E position or F position, the turning valve 26 is switched to the G position or the H position. At the same time, the pilot pressure from the pilot pump 17 acts on the pilot pressure receiving portion 31 of the pilot switching valve 27 via the remote control valve 14 and the shuttle valve 28, so that the pilot switching valve 27 operates from the tank communication oil passage position re. Change to the oil passage position. The pressure oil discharged from the main pump 15 passes through the oil passage 32, the N position of the pilot switching valve 27, the oil passages 33, 34, and the G position or the H position of the swirling valve 26, and is supplied to the two swivel motors 11 and 11 '. Supplied. Therefore, the two turning motors 11 and 11 'both perform normal rotation or reverse rotation in the same direction. However, when the operation lever 18 is returned to the neutral position, the pilot switching valve 27 moves to the tank communication oil passage position re,
Further, the swing valve 26 returns to the neutral position. The low pressure oil from the pilot pump 17 is supplied to the oil passages 35 and 36, the check valve 29, the oil passage 37,
34, through the oil passage 30 for the working pressure oil in the neutral position of the swirling valve 26, the swirling motors 11 and 11 'act on the ports and O at mutually opposite positions. That is, the low-pressure oil acts as a rotational force that causes the two turning motors 11 and 11 'to act in mutually opposite rotational directions. When the turning remote control valve 14 is in the neutral position as described above, the rotational forces in opposite directions act on the two turning motors 11 and 11 'due to the low pressure oil, respectively. The rattling between the meshing teeth with the turning pinion is eliminated. Therefore, the rattling of the upper swing body is reduced when the hydraulic excavator does not swing the swing body and finely operates the work attachment or excavates the backhoe bucket.

Note that FIG. 2 is a circuit diagram of a motor swing circuit according to another embodiment of the present invention. The circuit of FIG. 2 is different from that of FIG. 1 in that the swing motor control swing valves 38, 38 'are replaced by two swing motors 11, 1.
1'is provided separately. The function and function of the two-motor turning circuit is the same as in the case of FIG.

Effect of the Invention In the two-motor swing circuit of the present invention, an oil passage for working pressure oil is provided at the neutral position of the two-motor swing valve, and a pilot switching valve is provided in the oil passage communicating between the main pump and the swing valve. The pilot switching valve is set to be switchable in conjunction with the turning remote control valve. When the turning remote control valve is returned to the neutral position, the pilot switching valve is set to the tank communication oil passage position, and the low pressure oil is supplied to the two turning motors via the working pressure oil passage of the turning valve. The rotation forces act in opposite directions to each other. As a result, rattling between the meshing teeth of the internal ring gear of the inner ring and the turning pinion in the turning bearing of the construction machine is eliminated, and when the work attachment is slightly moved or excavated when not turning, the upper turning body The rattling can be reduced. Further, in the configuration of the two-motor swing circuit of the present invention, the inlet of the working pressure oil passage provided at the neutral position of the swing valve communicates with the discharge-side oil passage of the main pump, and the outlet is the forward rotation-side passage of one swing motor. Moreover, since the flow path is connected to the reverse rotation side flow path of the other swing motor, it is not necessary to provide another flow path in the supply / discharge circuit for operating the swing motor, and the circuit is simple. Also, a pilot switching valve is provided in the oil passage that connects the main pump and the swing valve, and when the swing valve is in the neutral position, the discharge oil from the main pump is returned to the oil tank through the tank communication oil passage position of the pilot switching valve. A swirl valve having an oil passage for working pressure can be formed compactly. Further, the discharge side oil passage of the pilot pump and the inlet of the working pressure oil passage are made to communicate with each other via a chuck valve that prevents backflow of pressure oil to the pilot pump side, so a simple pump with a single check valve A pressure acting circuit can be formed.

Therefore, in the construction machine equipped with the two-motor swing circuit of the present invention, rattling of the upper swing body during non-turning is reduced, so that the accuracy and fine movement operability of the work attachment operation are improved, and the maintenance of the construction machine is improved. The ride quality and ride quality can be improved.

[Brief description of drawings]

Fig. 1 is a two-motor swing circuit diagram according to the present invention, Fig. 2 is a second embodiment motor swing circuit diagram of the present invention, Fig. 3 is a side view of a large hydraulic excavator, and Fig. 4 is a large hydraulic excavator swing. FIG. 5 shows a cross-sectional side view of the main part of the apparatus, and FIG.
It is a motor turning circuit diagram. 3 …… Slewing bearing 6 …… Internal gear 11,11 ′ …… Swing motor 12,12 ′ …… Pinion 13,26,38,38 ′ …… Swing valve 14 …… Remote control valve 15,16 …… Main pump 17 …… Pilot pump 27 …… Pilot switching valve 30 …… Working oil passage

Claims (1)

[Scope of utility model registration request] 1. A slewing bearing having an internal gear is provided between an upper slewing body and a lower traveling body, and two slewing motors are installed in the upper slewing body, each of which has a pinion for a slewing motor and the above. When the swivel valve that engages with the internal gear and controls the rotation of the two swivel motors is returned to the neutral position, the pump pressure is applied to the forward rotation side flow path of one of the swivel motors. In a two-motor swing circuit of a construction machine that is introduced into the reverse rotation side flow path of the other swing motor, an oil passage for working pressure oil is provided at a neutral position of the swing valve, and an inlet of the oil passage for working pressure oil is provided. Communicates with the discharge side oil passage of the main pump, and the outlet communicates with the forward rotation side flow path of one swing motor and the reverse rotation side flow path of the other swing motor, and also connects the main pump with the swing valve. The pilot switching valve is installed in the oil passage The switching valve can be set to switch to the tank communication oil passage position when the turning remote control valve for turning valve switching control is in the neutral position, and to open the oil passage position when the turning remote control valve is in the operating position. The two-motor swirling circuit is characterized in that the discharge side oil passage and the inlet of the working pressure oil passage are communicated with each other through a check valve for preventing backflow of pressure oil to the pilot pump side.