Rotary drives for rotary positioning of working devices on machines or excavators

Abstract

The present invention relates to a rotary drive for rotary positioning of a working implement (25) on a machine or excavator (11), the rotary drive comprising said worm drive (46), a hydraulic motor (49) and a control circuit (44). At least one said pressure relief valve (61, 62) is provided between the first and second supply lines (51, 52), and the worm (47) and / or worm wheel (48) are designed with a thread pitch without self-locking (see Figure 4).

Description

[Technical Field]

[0001] The present invention relates to a rotary drive for the rotary positioning of a working implement on a machine or excavator. [Background technology]

[0002] Patent Document 1 discloses a rotary drive for rotationally positioning a working unit of an excavator. This rotary drive is composed of a worm drive including a helical worm and a worm wheel that meshes with it. Hydraulic motors are connected to both ends of the worm to drive the worms of the worm drive. The hydraulic motors are operated by a control circuit, and a second hydraulic motor can be optionally connected to the first hydraulic motor. This allows for easy control of different torques and rotational speeds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 102013206574 Summary of the Invention [Problem to be solved by the invention]

[0004] The invention is based on proposing a rotary drive for the rotary positioning of a working implement on a machine or excavator, which rotary drive allows for increased safety during working processes on the working implement. [Means for solving the problem]

[0005] This problem is solved by a rotary drive for rotary positioning of a work implement on an excavator. At least one pressure relief valve is provided between the first and second supply lines leading to the rotary drive. This pressure relief valve opens when the operating pressure of the hydraulic fluid in the pressurized supply line exceeds a certain level. The worm and / or worm wheel of the worm drive are designed with a non-self-locking thread pitch.

[0006] This prevents overloading of the rotary drive when working with the work implement. For example, in the case of a work implement designed as a demolition tool, the demolition tool may be tilted or positioned offset relative to the closing movement of the shears or gripper, causing excessive torque to act on the rotary drive when the shears or gripper are closed. As soon as a predetermined working pressure in the supply line exceeds a certain level, at least one pressure relief valve can release the working pressure in the supply line pressurized with hydraulic fluid, thereby reducing the excessive working pressure. At the same time, the worm drive, with a thread pitch designed without self-locking, allows the work tool to rotate relative to the excavator stick so that it is moved into a working position aligned with the object to be gripped. This not only prevents overloading of the rotary drive, but also prevents tilting of the machine or excavator, for example. When the work implement is in the aligned working position or gripping position, the work process can immediately continue.

[0007] Furthermore, it is preferable that at least one short-circuit line is provided between the first supply line and the second supply line, and at least one pressure relief valve is disposed in the at least one short-circuit line, thereby enabling the control circuit to be designed compactly.

[0008] Advantageously, first and second pressure relief valves are provided between the first and second supply lines, in particular in the respective short-circuit lines, and are arranged to act in opposite directions when the hydraulic fluid pressure increases, thereby providing equal effectiveness when the rotary drive is controlled to rotate left or right and when preventing overpressure.

[0009] The opening pressure of the at least one pressure relief valve can be adjusted or controlled, which allows different load cases to be predefined, making the rotary drive with control circuit universally suitable for light and heavy-duty applications, machines and excavators.

[0010] Advantageously, the first and second pressure relief valves are set to the same opening pressure, which ensures constant operating conditions regardless of the rotational movement of the rotary drive.

[0011] The pressure relief valve is advantageously designed for an opening pressure of 10 to 600 bar, in particular 40 to 380 bar.

[0012] According to a first embodiment, the opening pressure of the at least one pressure relief valve can be electrically adjustable or controlled in steps or continuously, and can be controlled by the machine or excavator operator advantageously from his working position.

[0013] To support the rotational movement of the worm wheel relative to the worm having a non-self-locking thread pitch, it is preferable to supply a lubricant to the worm drive. Such a lubricant allows the frictional resistance between the worm wheel and the worm to be determined, so that predetermined operating conditions can be set by adjusting the opening pressure of the pressure relief valve. Advantageously, a lubricant supply port is provided on the housing of the worm wheel or the housing of the rotary drive for supplying a lubricant, such as oil or grease, especially during maintenance.

[0014] The control circuit advantageously comprises a 4 / 2-way valve, which allows easy control of the left or right rotation and neutral position of the rotary drive without pressurizing one of the two supply lines.

[0015] Furthermore, at least one pressure relief valve is preferably located in or near the housing of the rotary drive on the load side between the switching valve and the hydraulic motor. This arrangement shortens the path from the worm wheel through the worm and hydraulic motor to the pressure relief valve, allowing the pressure relief valve to respond quickly and release load peaks when pressure increases. Placing the pressure relief valve near the hydraulic motor also provides high sensitivity. This increases safety, particularly by preventing the machine or excavator from rotating or tilting toward the object being gripped.

[0016] Furthermore, the control circuit preferably includes at least one secondary valve, which is provided on the operating side between the switching valve and the rotary drive to protect against absolute overload of the operating pressure in the supply line. The at least one secondary valve provides a safety device in the event of an absolute overload of the operating pressure in the hydraulic drive. The at least one secondary valve is preferably located remotely from the rotary drive or the hydraulic motor and its associated pressure relief valve, allowing for rapid activation of the safety function of the control circuit before the hydraulic motor is overloaded.

[0017] The adjustable opening pressure of the at least one pressure relief valve is preferably lower than the absolute overload opening pressure of the at least one secondary valve. [Brief explanation of the drawings]

[0018] The invention and other advantageous and further embodiments are explained in more detail below with reference to examples shown in the drawings, in which the features taken from this description and the drawings can be used according to the invention individually or in any combination. [Figure 1] FIG. 1 is a schematic side view of an excavator equipped with a working implement. [Figure 2] 2 is a perspective view of a mounting device for connecting to the excavator stick shown in FIG. 1; FIG. [Figure 3]FIG. 3 is a schematic side view of the mounting device shown in FIG. [Figure 4] FIG. 4 is a schematic diagram of a control circuit for the rotary drive of the mounting device of FIG. [Figure 5] FIG. 5 is a schematic cross-sectional view of a rotary drive with a worm drive. DETAILED DESCRIPTION OF THE INVENTION

[0019] FIG. 1 is a schematic side view of an excavator 11. The excavator 11 comprises a basic machine 13 having a boom 12, which is hinged at its end to a stick 14. The boom 12 is moved up and down by a lifting cylinder 19. The boom 12 is provided with at least one stick cylinder 18 for pivoting the stick 14. The stick 14 is provided with at least one pressure cylinder 16, which actuates a mounting device 21 mounted on the stick 14. The mounting device 21 is pivotally mounted on the end of the stick 14 at a mounting axis 17. The mounting device 21 may comprise a rotation device 22 equipped with a rotary drive 24 and a coupling, in particular a quick-change device 23. The rotation device 22 comprises a drive housing 66. The quick-change device 23 can be rotated relative to the drive housing 66 along the rotation axis 26 by the rotary drive 24. A working device 25 is interchangeably mounted on the quick-change device 23. The quick-change device 23 has a first changer half 41 provided on the work device side and a second changer half 42 provided on the rotary drive 24 side. The second changer half 42 is configured with at least one controllable latch 56. After a latch receiver 59 is positioned on a first latch bolt 55 of the first changer half 41, the latch 56 can be engaged with the rear of the second latch bolt 55 of the first changer half 41 to connect and lock the first and second changer halves 41, 42. Such a quick-change device is known, for example, from German Utility Model No. 202021101016.

[0020] A swivel-motion device 27 is provided for controlling the swivel movement of the mounting device 21. It comprises a deflector 28, which is articulated at one end to the stick 14 on a deflector axis 29. The swivel-motion device 27 further comprises a coupler 31, which is connected at one end to the deflector 28 via a common pivot axis 35. At its opposite end, the coupler 31 engages with a coupling device 33, which is a component of the mounting device 21 or is attached to it. Preferably, the drive housing 66 has an at least partially extending cover surface on which the coupling device 33 is provided. The pressure cylinder 16, in particular the piston rod of the pressure cylinder 16, engages with the pivot axis 35 of the swivel-motion device 27.

[0021] Fig. 2 is a perspective view of the mounting device 21. Fig. 3 is a schematic side view of the mounting device 21 shown in Fig. 2.

[0022] The coupling device 33 comprises two cheeks 36 arranged at a distance from one another. The cheeks 36 can be connected to at least one coupling plate 34 extending between the cheeks 36. The at least one coupling plate 34 can rest against the upper side of the rotation device 22 and is preferably removably fixed thereto. Each cheek 36 comprises a coupling bearing point 37 and a mounting bearing point 38. The coupling bearing point 37 and the mounting bearing point 38 are arranged with a height offset relative to one another. The mounting bearing point 38 is recessed relative to the coupling bearing point 37. The mounting bearing point 38 can be offset toward or within a rotation plane 39 of the rotation device 22. The mounting bearing point 38 is offset laterally outward relative to the mounting device 21, in particular the rotation device 22, or is assigned to an end face of the rotation device 22.

[0023] The rotating device 22 also has a rotary feedthrough 71 through which hydraulic lines can be supplied to the rotating device 22 for connection to the working device 25. In this way, other drives can be controlled, such as, for example, shear, gripper or vibrator drives.

[0024] FIG. 4 schematically shows a control circuit 44 of the rotary drive 24 for controlling the rotational movement of the rotating device 22 or the working device 25. A worm drive 46 is provided within a housing 45 of the rotary drive 24. The worm 47 is meshed with a worm wheel 48. A hydraulic motor 49 is connected to one end of the worm 27. The hydraulic motor may be, for example, an axial piston motor, a radial piston motor, or a gear piston pump motor. The hydraulic motor 49 is controlled via a first supply line 51 and a second supply line 52. These supply lines 51 and 52 are connected to a selector valve 53. The selector valve 53 is preferably a 4 / 2-way valve.

[0025] The switching valve 53 is connected to a tank 57 via a hydraulic line 68. The pump 54 sends hydraulic fluid from the tank 57 to the switching valve 53 via the hydraulic line 68. Furthermore, a hydraulic line 69 that opens into the tank 57 is connected to the switching valve 53 as a return flow path.

[0026] The control circuit 44 has a drive-side region extending between the tank 57 and the switching valve 53. The control circuit 44 has a work-side region extending between the hydraulic motor 49 and the switching valve 53.

[0027] Depending on the switching position of the switching valve 53, the first supply line 51 can be pressurized with the working pressure of the hydraulic fluid. In this case, the rotary drive 24 is operated in a first rotational direction, for example, clockwise. The second supply line 52 is used to return the hydraulic fluid to the tank 57. After switching the switching valve 53, the second supply line 52 can be pressurized with the working pressure to change the rotational direction of the hydraulic motor 49, for example, counterclockwise. In this way, both the first supply line 51 and the second supply line 52 can form an inlet to or an outlet from the hydraulic motor 49.

[0028] At least one pressure relief valve 61, 62 is provided between the first and second supply lines 51, 52. For example, a first short-circuit line 63 equipped with the first pressure relief valve 61 and a second short-circuit line 64 equipped with the second pressure relief valve 62 are provided. The first and second pressure relief valves 61, 62 are designed to act in opposite directions when the pressure of the hydraulic fluid increases. That is, when the operating pressure of the supply line 51 increases and when the operating pressure of the supply line 52 increases, the pressure relief valves 61, 62 can be quickly opened to prevent excessive pressure from being applied to the rotary drive unit 24.

[0029] At least one secondary valve 60 is provided in the operating region of the control circuit 44. The at least one secondary valve 60 is directly associated with the directional control valve 53. Preferably, the directional control valve 53 and the one secondary valve 60 are arranged in the superstructure of the excavator 11. Preferably, each supply line 51, 52 is connected to a secondary valve 60. This secondary valve 60 serves to prevent absolute overload of the operating pressure in the supply lines 51, 52. In the event of an absolute overload, the hydraulic fluid is immediately returned to the tank 57, and the pressure is relieved before the hydraulic motor 49 is pressurized. At least one pressure relief valve 61, 62 can be provided in the attachment device 21, preferably in the housing 45 of the rotary drive 24. The at least one pressure relief valve 61, 62 can also be provided near the rotary drive 24. This positioning can also be on the stick 14 adjacent to the coupling device 33. The proximity of at least one pressure relief valve 61, 62 to the hydraulic motor 49 allows load peaks to be quickly reduced and provides thorough overload protection.

[0030] 5 is a schematic cross-sectional view of the rotary drive unit 24. A worm 47 is supported at both ends. A hydraulic motor 49 is engaged with one end of the worm 47. The worm 47 drives a worm wheel 48, the rotation axis of which is located on the rotation axis 26 of the rotation device 22.

[0031] The rotary drive unit 24 equipped with the above-described control circuit 44 improves sensitivity when an overload occurs on the load side or the working side. The setting range of the drive-side overload pressure relief valves 61, 62 for controlling the hydraulic motor 49 is set to a value below or above the absolute overload at which the at least one secondary valve 60 opens. This improves the safety of the work. This will become clear in the following exemplary application example.

[0032] The working device 25 may be configured as, for example, shears, particularly demolition shears. When the shears are open, they are positioned at an angle or twisted position relative to the object to be gripped. If the shears are closed in this state, the tilted position may prevent the shears from cutting the object. However, in this case, the pump 54 increases pressure, generating excessive pressure in the control circuit 44, particularly on the load side, which could cause the entire machine or excavator 11 to tilt toward the object to be gripped. However, the control circuit 44 is preferably set lower than the absolute overload limit, and one of the pressure limiting valves 61 and 62 opens on the load side in the event of excessive pressure exceeding the set operating pressure. This stops the supply of hydraulic fluid to the hydraulic motor 49 and interrupts control of the rotational movement. Because the worm drive mechanism 46 is not self-locking, the shears can align themselves with the object to be gripped. As a result, the machine or excavator 11 does not rotate toward the object to be gripped and remains stationary. The work process can then be continued by controlling the closing movement of the scissors or working device.

Claims

1. A rotary drive for the rotary positioning of a working device (25) on a machine or excavator (11), comprising: a worm drive unit (46) consisting of a helical worm (47) and the worm wheel (48) that mesh with each other; a hydraulic drive unit (50) consisting of at least one hydraulic motor (49) and a control circuit (44) connected thereto; Equipped with The hydraulic motor (49) acts on one axial end of the screw (47), The control circuit (44) includes a switching valve (53) that controls first and second supply lines (51, 52) that communicate with at least one of the hydraulic motors (49), and the first supply line (51) is supplied with hydraulic fluid for controlling rotation of the rotary drive unit (24) in a first direction, and the second supply line (52) is supplied with hydraulic fluid for controlling rotation of the rotary drive unit (24) in a second direction. At least one pressure relief valve (61, 62) is provided between the first and second supply lines (51, 52), and when the operating pressure of the hydraulic fluid in the first and second supply lines (51, 52) pressurized with the hydraulic fluid exceeds a certain level, the pressure relief valve opens; the worm (47) and / or the worm wheel (48) are designed with a thread pitch that does not involve self-locking; A rotary drive unit characterized by:

2. At least one short-circuit line (63, 64) is provided between the first and second supply lines (51, 52), and at least one pressure relief valve (61, 62) is provided in the at least one short-circuit line (63, 64).

2. The rotary drive according to claim 1, characterized in that:

3. a first pressure relief valve (61) and a second pressure relief valve (62) connected between the first and second supply lines (51, 52), the first and second pressure relief valves opening in opposite directions when the pressure of the hydraulic fluid in the first and second supply lines (51, 52) increases; 3. The rotary drive unit according to claim 1 or 2, characterized in that:

4. the opening pressure of at least one of the pressure relief valves (61, 62) is adjustable or controllable; 4. The rotary drive unit according to claim 1, wherein the rotary drive unit is a rotary drive unit.

5. The first and second pressure relief valves (61, 62) are adjustable to the same opening pressure.

5. A rotary drive unit according to claim 1, wherein the rotary drive unit is a rotary drive unit.

6. at least one of the pressure relief valves (61, 62) is adjustable to an opening pressure between 10 bar and 600 bar; 6. A rotary drive according to claim 1, wherein the rotary drive is a rotary drive unit.

7. the opening pressure of at least one of the pressure relief valves (61, 62) is electrically adjustable or switchable in steps or continuously; 7. A rotary drive according to claim 1, wherein the rotary drive is a rotary drive.

8. A lubricant is supplied to the worm drive (46).

8. A rotary drive according to claim 1, characterized in that it comprises:

9. The lubricant can be supplied from the outside into the housing (45) of the worm drive unit (46) through a lubricant supply port.

9. The rotary drive unit according to claim 8.

10. The switching valve (53) is designed as a 4 / 2-way valve.

10. Rotary drive unit according to claim 1, characterized in that it comprises a first rotor and a second rotor.

11. at least one pressure relief valve (61, 62) is arranged in or near the housing (45) of the rotary drive (24) on the load side between the switching valve (53) and the hydraulic motor (49); 11. Rotary drive according to any one of claims 1 to 10, characterized in that it comprises:

12. the control circuit (44) has at least one secondary valve (60) on the operating side between the switching valve (53) and the rotary drive (24), which secondary valve is provided to protect the first and second supply lines (51, 52) from absolute overloads on their operating pressures, preferably adjustable, and opens when an absolute overload is reached; 12. Rotary drive according to any one of claims 1 to 11, characterized in that it comprises:

13. the adjustable opening pressure of the at least one pressure relief valve (61, 62) is less than the absolute overload opening pressure of the at least one secondary valve (60); 13. Rotary drive according to any one of claims 1 to 12, characterized in that it comprises:

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