boom rotation mechanism, boom and construction machinery

Abstract

This invention relates to the field of booms and discloses a boom rotation mechanism, a boom, and engineering machinery. The boom rotation mechanism includes an outer ring (8) and an inner ring (17) nested around a central axis, a guide portion, and a driving component. One of the outer ring (8) and the inner ring (17) is provided with a circumferentially extending wave-shaped guide rail. The driving component can drive the guide portion to move axially relative to the other of the outer ring (8) and the inner ring (17), so that the guide portion acts axially on the guide rail, thereby driving the guide rail to slide circumferentially relative to the guide portion, so as to drive the inner ring (17) and the outer ring (8) to rotate relative to each other around the central axis. Through the above technical solution, the relative rotation of the inner ring can be realized by driving the guide portion to move axially through the driving component. Its structure is relatively simple, with relatively few parts, suitable for the drive structure between boom sections, and the overall weight is smaller, achieving lightweighting.

Description

Technical Field

[0001] This invention relates to the field of booms, specifically to a boom rotation mechanism, to a boom, and to a type of engineering machinery. Background Technology

[0002] As the main load-bearing and moving component of construction machinery, the boom is usually composed of multiple boom sections hinged together. It is extended and retracted by the hydraulic cylinders of each boom section. The relative angle between two adjacent boom sections is a key factor affecting the boom's flexibility and working range. The larger the relative angle between two adjacent boom sections, the greater the boom's flexibility and working range, and vice versa.

[0003] Currently, most boom systems have a maximum relative angle of no more than 280° between adjacent boom sections. This is sometimes insufficient to meet the material placement requirements in complex construction environments, especially when the boom system needs to avoid obstacles. The limited relative angle makes it difficult to deploy the boom system into the required posture. Furthermore, the boom section connection method, which uses cylinders and hinged plates, results in a very limited range of motion during boom deployment; the boom sections can only be deployed clockwise or counterclockwise. Moreover, when the relative angle of the boom sections is large, retracting the boom requires rotating a very large angle in the opposite direction, significantly reducing the boom's flexibility and work efficiency.

[0004] In addition, the relative angular velocity of the boom segments is not proportional to the stroke of the cylinder. As the relative rotation angle changes, the angular velocity of the boom segments also changes. Furthermore, due to the long boom segments, a "magnification" effect is formed at the end. This fluctuation will significantly reduce the stability and accuracy of the boom end.

[0005] Therefore, it is important to improve the connection method between boom sections to enhance the flexibility and stability of the boom. Summary of the Invention

[0006] The purpose of this invention is to provide a boom rotation mechanism to solve the problems of complex structure, poor stability and small rotation angle range in the prior art.

[0007] To achieve the above objectives, the present invention provides a boom rotation mechanism, wherein the boom rotation mechanism includes an outer ring and an inner ring nested around a central axis, a guide portion, and a driving member. One of the outer ring and the inner ring is provided with a circumferentially extending wave-shaped guide rail. The driving member can drive the guide portion to move axially relative to the other of the outer ring and the inner ring, so that the guide portion acts axially on the guide rail, thereby driving the guide rail to slide circumferentially relative to the guide portion, so as to drive the inner ring and the outer ring to rotate relative to each other around the central axis.

[0008] The guide rail is provided on the outer periphery of the inner ring, and an axially extending spline is provided on one of the inner periphery of the outer ring and the guide portion, while a spline groove is provided on the other to accommodate the axial movement of the spline.

[0009] The guide portion includes a ring body disposed between the inner ring and the outer ring, and a rolling element disposed on the inner circumference of the ring body. The rolling element is capable of acting axially on both sides of the guide rail.

[0010] The outer ring is provided with an axially extending strip-shaped hole, the guide portion includes an ear plate disposed on the outer periphery of the ring body and passing through the strip-shaped hole, and the driving member is pulsatorically connected to the ear plate.

[0011] The extension path of the guide rail, in its planar unfolded state, is a sine or cosine curve comprising an integer number of periods.

[0012] The inner ring is provided with two guide rails spaced axially apart. The boom rotation mechanism includes two guide parts with rolling elements on the two guide parts aligned axially. The crest of one guide rail is offset from the crest and trough of the other guide rail, and the trough of one guide rail is offset from the crest and trough of the other guide rail.

[0013] The two guide rails have the same shape and a phase difference of 45 degrees.

[0014] The driving component includes a hydraulic cylinder, one end of which is fixed relative to the outer ring, and the other end is connected to the ear plate.

[0015] In addition, the present invention also provides a boom, wherein the boom includes the boom rotation mechanism described in the above solution.

[0016] In addition, the present invention also provides an engineering machine, wherein the engineering machine is equipped with the boom described in the above solution.

[0017] The above technical solution enables the relative rotation of the inner ring by driving the guide part to move axially through the driving component. Its structure is relatively simple and has relatively few parts. It is suitable for the drive structure between boom sections and has a smaller overall weight, thus achieving lightweighting. Attached Figure Description

[0018] Figure 1 This is a perspective view of the boom rotation mechanism according to an embodiment of the present invention;

[0019] Figure 2 This is an exploded view of the boom rotation mechanism according to an embodiment of the present invention;

[0020] Figure 3This is a perspective view of the guide portion and the hydraulic cylinder according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram showing the cooperation between the guide portion and the inner ring according to an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the cooperation between the rolling element and the guide groove according to an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures

[0024] 1-First end cap, 2-First bearing, 3-First hydraulic cylinder, 4-First guide part, 5-First ring body, 6-First ear plate, 7-First rolling element, 8-Outer ring, 9-Strip hole, 10-Second guide part, 11-Second ring body, 12-Second ear plate, 13-Second rolling element, 14-Second hydraulic cylinder, 15-Second bearing, 16-Second end cap, 17-Inner ring, 18-First guide groove, 19-Second guide groove. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] This invention provides a boom rotation mechanism, see reference. Figures 1-4 As shown, the boom rotation mechanism includes an outer ring 8 and an inner ring 17 nested around a central axis, a guide portion, and a drive component. One of the outer ring 8 and the inner ring 17 is provided with a circumferentially extending wave-shaped guide rail. The drive component can drive the guide portion to move axially relative to the other of the outer ring 8 and the inner ring 17, so that the guide portion acts axially on the guide rail, thereby driving the guide rail to slide circumferentially relative to the guide portion, so as to drive the inner ring 17 and the outer ring 8 to rotate relative to each other around the central axis.

[0027] The outer ring 8 and the inner ring 17 can rotate relative to each other around the central axis. They are respectively connected to two adjacent arm segments, which allows the two arm segments to rotate relative to each other.

[0028] One of the outer ring 8 and the inner ring 17 is provided with a wave-shaped guide rail, on which a wave-shaped force-bearing surface is formed; the guide part is axially movable in conjunction with the other of the outer ring 8 and the inner ring 17. When the guide part moves axially, it acts on the guide rail. The force-bearing surface at the guide rail has a non-right angle with both the axial direction and the circumferential direction. The force of the guide part can be decomposed into a circumferential component, thereby causing the guide rail to rotate around the central axis in the circumferential direction, so that the outer ring 8 and the inner ring 17 rotate around the central axis.

[0029] Regarding the shape of the guide rail, the waveform refers to the undulation of its extension path, which makes the extension path form non-right angles with both the axial and circumferential directions. This causes the force exerted by the guide part on the guide rail to form a circumferential component, thereby driving the guide rail to rotate. The waveform can be a sine or cosine curve or a simple deformation as described below, as long as most of it has non-right angles with the axial and circumferential directions.

[0030] The movement of the guide can be axial reciprocating motion, and it is circumferentially stationary relative to the other of the outer ring 8 and inner ring 17.

[0031] The driving component can provide power for the axial movement of the guide part, and it can be a linear driving component such as a cylinder or hydraulic cylinder.

[0032] This design contains several movable parts, now referred to as... Figure 2 The relative motion relationship between multiple components is explained. In this embodiment, the guide rail is disposed on the inner ring 17, while the guide portion can reciprocate axially relative to the outer ring 8 but cannot rotate circumferentially. In the relative motion relationship between the guide rail and the guide portion, the guide portion engages with a very short portion of the guide rail. With the guide rail as a reference, the motion trajectory of the guide portion is the waveform extension trajectory of the guide rail. Conversely, with the guide portion as a reference, the motion trajectory of the guide rail is also the same waveform extension trajectory of the guide rail. When the outer ring 8 is used as a reference frame, since the guide portion can move axially, the guide rail and the inner ring 17 on which it is located rotate around the central axis relative to the outer ring 8. In particular, the inner ring 17 is configured to only rotate relative to the outer ring 8 and cannot move axially.

[0033] In this solution, the guide part is driven to move axially by the driving component, which can realize the relative rotation of the inner ring. Its structure is relatively simple and has relatively few parts. It is suitable for the drive structure between boom sections, and the overall weight is smaller, thus achieving lightweighting.

[0034] Optionally, the guide rail is provided on the outer periphery of the inner ring 17, and one of the inner periphery of the outer ring 8 and the guide portion is provided with an axially extending spline, while the other is provided with a spline groove to accommodate the axial movement of the spline. The guide rail is disposed on the outer peripheral surface of the inner ring 17, and the guide portion is at least partially disposed between the inner ring 17 and the outer ring 8. The surface of the guide portion facing the outer ring 8 is provided with a spline or spline groove, while the inner peripheral surface of the outer ring 8 is provided with a spline groove or spline. The spline is slidably accommodated in the spline groove, allowing the guide portion to move axially relative to the outer ring 8 and restricting the rotation of the guide portion relative to the outer ring 8.

[0035] The guide portion includes a ring body disposed between the inner ring 17 and the outer ring 8, and rolling elements disposed on the inner circumference of the ring body. The rolling elements are capable of axially acting on both axial sides of the guide rail. The main body of the guide portion is ring-shaped, for example... Figure 2The first ring 5 of the first guide portion 4 and the second ring 11 of the second guide portion 10 are shown. A first rolling element 7 is provided on the inner circumference of the first ring 5, and a second rolling element 13 is provided on the inner circumference of the second ring 11. The guide rail can take various forms, such as a recessed guide groove or a protruding guide bar, and two axially spaced elements can be provided. Both guide grooves and guide bars have axially spaced sides. For guide grooves, the rolling elements can be accommodated therein, acting on both sides of the groove during axial movement. For guide bars, the rolling elements are located on at least one side of their axial sides (rolling elements can be provided on both sides of the guide bar to hold it), allowing relative sliding, thus enabling the guide portion to move along a wave-like trajectory relative to the guide rail. The rolling elements can be rollers with their rotation axis extending radially along the ring body, allowing the guide portion to slide more easily relative to the guide rail, or they can be balls.

[0036] Additionally, the outer ring 8 is provided with an axially extending strip-shaped hole, and the guide portion includes an ear plate disposed on the outer periphery of the ring body and passing through the strip-shaped hole; the driving member is pulsatorically connected to the ear plate. (Reference) Figure 2 As shown, a first ear plate 6 is provided on the outer periphery of the first ring body 5, which extends through the strip hole on the outer ring 8 to the outside of the outer ring 8 to connect with the driving member (first hydraulic cylinder 3). A second ear plate 12 is provided on the outer periphery of the second ring body 11, which extends through the strip hole on the outer ring 8 to the outside of the outer ring 8 to connect with the driving member (second hydraulic cylinder 14).

[0037] The extension path of the guide rail, in its planar unfolded state, is a sine or cosine curve comprising an integer number of periods. The extension path of the guide rail completely covers the entire circumference of the inner ring 17, and the guide rails connect end-to-end to form a closed path. The extension shape of the guide rail is a sine or cosine curve, and includes an integer number of periods.

[0038] Optionally, the inner ring 17 is provided with two axially spaced guide rails, and the boom rotation mechanism includes two guide portions with rolling elements on the two guide portions aligned axially. The crests of one guide rail are offset from the crests and troughs of the other guide rail, and the troughs of one guide rail are offset from the crests and troughs of the other guide rail. (Reference) Figure 2 and Figure 4As shown, two axially spaced guide rails, namely a first guide groove 18 and a second guide groove 19, are provided on the outer periphery of the inner ring 17. The crests of the first guide groove 18 and the crests and troughs of the second guide groove 19 are not aligned, and the troughs of the first guide groove 18 and the crests and troughs of the second guide groove 19 are also not aligned. This is because, at positions outside the crests or troughs, the angle between the side of the guide groove portion contacted by the rolling element and the axial direction is not a right angle, thus a circumferential component force can be formed. However, at the crests or troughs, the side of the guide groove portion contacted by the rolling element is at a right angle to the axial direction, and the axial force cannot form a circumferential component force, thus failing to drive the inner ring to rotate relative to each other. Therefore, two sets of guide parts and guide rails are provided. If the guide part in one set cannot provide a circumferential component force, the other set will necessarily provide a circumferential component force. That is, regardless of the relative position of the inner ring 17 and the outer ring 8, the inner ring 17 can be started to rotate.

[0039] Optionally, the two guide rails have the same shape and a phase difference of 45 degrees. The shape of the guide rail mainly refers to the shape of its extension path. The waveforms in each individual cycle of the first guide groove 18 and the second guide groove 19 are the same, including amplitude and wavelength, and have the same number of individual cycle waveforms.

[0040] The driving component includes a hydraulic cylinder, one end of which is fixed relative to the outer ring 8, and the other end is tractively connected to the ear plate. The driving component includes a first hydraulic cylinder 3 and a second hydraulic cylinder 14. The first hydraulic cylinder 3 is connected to the first guide portion 4 to drive the first guide portion 4 to reciprocate, and the second hydraulic cylinder 14 is connected to the second guide portion 10 to drive the second guide portion 10 to reciprocate. (Reference) Figure 1 and Figure 2 As shown, one end of the first hydraulic cylinder 3 is fixed to the first end of the outer ring 8. Figure 2 The left end of the second cylinder 14 is connected to the first ear plate 6 of the first guide part 4, and the other end is fixed to the second end of the outer ring 8. Figure 2 The first guide 4 is located on the right side of the second guide 10, that is, closer to the second end of the outer ring 8 than the second guide 10. The first cylinder 3 extends between adjacent second cylinders 14, and the second cylinder 14 also extends between two adjacent first cylinders 3. The first cylinder 3 and the second cylinder 14 are interleaved. If the sum of the overall lengths of the first cylinder 3 and the second cylinder 14 is greater than the outer ring 8, it can be installed on the outer ring 8, reducing the axial length.

[0041] The extension paths of the first guide groove 18 and the second guide groove 19 can each include three cycles, that is, three sets of peaks and troughs, as shown in the reference. Figure 2As shown, the first guide section 4 is provided with three circumferentially distributed first rolling elements 7 (rollers), and the second guide section 10 is provided with three circumferentially distributed second rolling elements 13 (rollers), each rolling element corresponding to one cycle of the waveform of the guide rail.

[0042] In addition, the boom rotation mechanism also includes a first bearing 2 and a second bearing 15, a first end cap 1 and a second end cap 16. The first bearing 2 and the second bearing 15 can be installed in the two ends of the outer ring 8 respectively to support the inner ring 17 to rotate in the outer ring 8. The first end cap 1 and the second end cap 16 (both are annular) are respectively provided at the two ends of the outer ring 8 to fix the first bearing 2 and the second bearing 15 respectively.

[0043] In addition, the inner ring 17 can extend partially relative to the inner ring 17, and the extended part serves as the part connected to the arm segment, on which a spline or spline groove can be provided.

[0044] refer to Figure 5 The following is a description of the principle of the boom rotation mechanism in this solution.

[0045] 1. The two simple harmonic curve-shaped guide grooves on the outer wall of the inner ring 17 are 45° out of phase, such as... Figure 5 As shown, Figure 5 The middle curve is Figure 4 The central groove is laid out flat and simplified. The first rolling element 7 of the first guide part 4 is placed in the first guide groove 18 and driven by the first hydraulic cylinder 3; the second rolling element 13 of the second guide part 10 is placed in the second guide groove 19 and driven by the second hydraulic cylinder 14. When the first rolling element 7 moves to the zero position, the second rolling element 13 moves to the extreme position, and the two are exactly 45° out of phase. Figure 5 The midpoint f and point F are shown.

[0046] 2. The two harmonic guide grooves on the outer wall of the inner ring 17 have three cycles, each corresponding to one of the three evenly distributed rollers and three hydraulic cylinders. That is, each pair of second hydraulic cylinders 14 and second rolling elements 13 corresponding to the second guide section 10 performs the same movement, as does the first guide section 4. Therefore, the subsequent analysis will only focus on one set of moving components.

[0047] 3. Taking the first rolling element 7 as an example, since the first guide portion 4 is connected to the outer ring 8 via a spline, the first guide portion 4 will not rotate. When the first cylinder 3 extends, the first rolling element 7 will be squeezed against the inner wall of the slide, and the squeezing action will force the inner ring 17 to rotate. As the squeezing action continues, the inner ring 17 can achieve a 360° rotational movement.

[0048] 4. When the first rolling element 7 reaches its extreme position, which is the dead point of the cam mechanism, the first cylinder 3 should not provide pressure at this time, otherwise it will cause damage to the mechanism. At this exact moment, the second rolling element 13 reaches its zero position, at which point the cam mechanism's transmission angle is at its maximum. The second cylinder 14 should then provide pressure to force the inner ring 17 to rotate, causing the first rolling element 7 to pass the extreme (dead) position. Similarly, when the second rolling element 13 reaches its extreme position, and the first rolling element 7 reaches its zero position, the first cylinder 3 should drive the first guide part 4 to move, forcing the inner ring 17 to rotate, causing the second rolling element 13 to pass the extreme point. This alternating cycle continuously drives the inner ring 17 to rotate. Figure 5 The midpoint f and point F are shown.

[0049] 5. When the first rolling element 7 moves to near its extreme position (but not yet at its extreme position), although the cam mechanism has not reached its dead point, the transmission angle of the mechanism is very small, resulting in low working efficiency. Meanwhile, the second rolling element 13 moves to near its zero position, resulting in a large transmission angle of the cam mechanism and high working efficiency. Therefore, when the first cylinder 3 drives the first rolling element 7, the second cylinder 14 acts as a follower. When it moves to near its extreme position, the first cylinder 3 needs to stop supplying pressure and become a follower, while the second cylinder 14 begins to supply pressure, driving the second rolling element 13 and carrying the first rolling element 7 through the low-efficiency region. Therefore, the left and right cylinders actually operate alternately, achieving a 360° rotation of the inner ring 17.

[0050] 6. To ensure that the cams operate in their most efficient range during alternating motion as described in point 5, the alternating motion should occur between the zero and extreme positions. This guarantees the transmission efficiency of both rolling elements simultaneously. Figure 5 The four positions of 45°, 135°, 225°, and 315° are shown within one cycle.

[0051] 7. The alternating movement positions described in 6 above correspond to the working range of the first rolling element 7 as segments bc and de, and the working range of the second rolling element 13 as segments AB and CD. For example... Figure 5 As shown, these regions are all located near the zero point of the simple harmonic curve. At this time, the simple harmonic curve is close to a straight line. Since the cylinder's operating speed can be kept at a constant value by controlling the flow rate of the hydraulic oil, when the cylinder works in the above regions, the angular velocity of the inner ring 17 is approximately linearly related to the cylinder displacement. This allows the angular velocity of the inner ring 17 to be controlled within a very small fluctuation range, greatly improving the stability and safety of the boom rotation.

[0052] refer to Figure 5 The following is the sequence of actions of the boom rotation mechanism within one cycle during clockwise rotation:

[0053] 1. In segment AB (ab), the first hydraulic cylinder 3 is a follower, and the second hydraulic cylinder 14 provides pressure. The second hydraulic cylinder 14 extends, forcing the inner ring 17 to rotate clockwise.

[0054] 2. In section BC (bc), the second cylinder 14 is a follower, the first cylinder 3 provides pressure, the first cylinder 3 retracts, forcing the inner ring 17 to rotate clockwise;

[0055] 3. In the CD (cd) segment, the first hydraulic cylinder 3 is a follower, and the second hydraulic cylinder 14 provides pressure. When the second hydraulic cylinder 14 retracts, it forces the inner ring (8) to rotate clockwise.

[0056] 4. In the DE (de) segment, the second oil cylinder 14 is a follower, the first oil cylinder 3 provides pressure, the first oil cylinder 3 extends, forcing the inner ring 17 to rotate clockwise, achieving 360° rotation.

[0057] To make the mechanism move counterclockwise, the principle is the same as the steps above, only the extension and retraction actions of the hydraulic cylinder need to be switched.

[0058] The transmission principle in this invention is a roller push rod cam mechanism, which can greatly reduce wear between moving components. The guide rail has a simple harmonic curve profile, which will not cause significant impact on the mechanism, making the boom rotation more stable and safer. The motion profile is a 3-cycle simple harmonic curve. If the boom rotates one revolution, each hydraulic valve only needs to switch directions 12 times. The low switching frequency makes the rotating mechanism highly efficient and has a long service life, greatly improving the life of hydraulic components. It can achieve a 360° relative rotation angle of the boom, greatly improving the boom's working range and flexibility. The cylinder's action area is near the zero position of the simple harmonic curve, and the profile is approximately a straight line. The mechanism has high transmission efficiency, smooth transmission, and low impact, greatly improving the boom's working efficiency and stability.

[0059] In addition, the present invention also provides a boom, wherein the boom includes the boom rotation mechanism described in the above embodiments. The boom includes multiple boom sections, and the rotation drive mechanism can be installed on two adjacent boom sections to drive the two boom sections to rotate relative to each other. Alternatively, the last boom section of the boom may be provided with other rotatable structures, such as concrete conveying pipes, which can be driven to rotate by the rotation drive mechanism.

[0060] Furthermore, the present invention also provides an engineering machinery, characterized in that the engineering machinery is equipped with the boom described in the above-described scheme. The engineering machinery can be a concrete truck, crane, or other aerial work platform, and its boom assembly is equipped with the rotary drive mechanism described above.

[0061] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A boom rotation mechanism, characterized in that, The boom rotation mechanism includes an outer ring (8) and an inner ring (17) nested around a central axis, a guide part, and a driving member. The inner ring (17) cannot move axially relative to the outer ring (8). A circumferentially extending wave-shaped guide rail is provided on the outer periphery of the inner ring (17). The driving member can drive the guide part to move axially relative to the outer ring (8), so that the guide part acts on the guide rail axially, thereby driving the guide rail to slide circumferentially relative to the guide part, so as to drive the inner ring (17) and the outer ring (8) to rotate relative to each other around the central axis. Among them, one of the inner circumference of the outer ring (8) and the guide portion is provided with an axially extending spline, and the other is provided with a spline groove to accommodate the axial movement of the spline. The guide portion includes a ring body disposed between the inner ring (17) and the outer ring (8) and a rolling element disposed on the inner circumference of the ring body. The rolling element can act axially on both sides of the guide rail. The outer ring (8) is provided with an axially extending strip hole, the guide part includes an ear plate disposed on the outer periphery of the ring body and passing through the strip hole, and the driving component includes a hydraulic cylinder, one end of which is fixed relative to the outer ring (8) and the other end is connected to the ear plate for transmission.

2. The boom rotation mechanism according to claim 1, characterized in that, The extension path of the guide rail, when unfolded in a plane, is a sine or cosine curve comprising an integer number of periods.

3. The boom rotation mechanism according to claim 2, characterized in that, The inner ring (17) is provided with two guide rails spaced axially apart. The boom rotation mechanism includes two guide parts, and the rolling elements on the two guide parts are aligned axially. The crest of one guide rail is offset from the crest and trough of the other guide rail, and the trough of one guide rail is offset from the crest and trough of the other guide rail.

4. The boom rotation mechanism according to claim 3, characterized in that, The two guide rails are identical in shape and have a phase difference of 45 degrees.

5. A boom, characterized in that, The boom includes the boom rotation mechanism as described in any one of claims 1-4.

6. An engineering machinery, characterized in that, The construction machinery is equipped with the boom as described in claim 5.

Images