Lower frame and engineering machinery

Abstract

The utility model relates to the technical field of engineering machinery, and discloses a lower vehicle frame and engineering machinery. The lower vehicle frame comprises a first edge beam, a loading frame, a second edge beam and a jacking device. The first side and the second side of the loading frame are each provided with a sliding block, the first edge beam and the second edge beam are each provided with a sliding connection structure, the sliding block on the first side of the loading frame is connected with the sliding connection structure on the first edge beam in a sliding mode and can slide up and down, and the sliding block on the second side of the loading frame is connected with the sliding connection structure on the second edge beam in a sliding mode and can slide up and down. And jacking devices are arranged on the first edge beam and the second edge beam. Under the guidance of relative up-and-down sliding between the sliding block and the sliding connection structure, the jacking device can be used for driving the loading frame to move up and down relative to the first edge beam and the second edge beam. For terrains such as forest land or mountain land where the height of the loading frame needs to be increased. The jacking device can be used for driving the load-carrying frame to move up and down according to requirements so as to adjust the height of the load-carrying frame to adapt to terrains.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, specifically to a chassis and engineering machinery. Background Art

[0002] Construction machinery refers to a class of mechanical equipment used for construction, repair, maintenance, and dismantling, designed to solve various construction, repair, and maintenance tasks, such as excavators and loaders. Various types of construction machinery include working mechanisms for construction and traveling mechanisms for movement. The working mechanism is connected to the traveling mechanism via a lower frame. The traveling mechanism enables the working mechanism to move to the work position for construction work. The lower frame includes a load-bearing frame (X-frame) and left and right beams connected to both sides of the load-bearing frame. The working mechanism is connected to the load-bearing frame, and the left and right beams are connected to the traveling mechanism.

[0003] The existing underframe has its left and right beams welded to the load frame, making it impossible to adjust the height of the load frame and unsuitable for terrains such as woodlands or mountains where the load frame needs to be raised. Utility Model Content

[0004] In view of this, this application provides a chassis and engineering machinery to solve the problem that the height of the load-bearing frame cannot be adjusted in existing chassis.

[0005] In a first aspect, this application provides a lower frame, comprising: a first side beam, a load-bearing frame, a second side beam, and a lifting device, wherein...

[0006] The first and second sides of the load-bearing frame are each provided with a slider, and the first and second side beams are each provided with a sliding joint structure. The slider on the first side of the load-bearing frame is slidably connected to the sliding joint structure on the first side beam and can slide up and down. The slider on the second side of the load-bearing frame is slidably connected to the sliding joint structure on the second side beam and can slide up and down.

[0007] The lifting device is provided on both the first side beam and the second side beam, and the lifting device is adapted to lift or lower the load frame.

[0008] Beneficial effects: When the load-bearing frame needs to be raised, the lifting device extends upwards to lift it, causing it to move upwards. At this time, the slider on the first side of the load-bearing frame slides upwards relative to the sliding structure on the first side beam, and the slider on the second side slides upwards relative to the sliding structure on the second side beam, guiding the frame's ascent. When the load-bearing frame needs to be lowered, the lifting device retracts downwards, and the load-bearing frame moves downwards under its own weight. At this time, the slider on the first side of the load-bearing frame slides upwards relative to the sliding structure on the first side beam, and the slider on the second side slides upwards relative to the sliding structure on the second side beam, guiding the frame's ascent. Guided by the relative up-and-down sliding between the sliders and the sliding structures, the lifting device can drive the load-bearing frame to move up and down relative to the first and second side beams. For terrains such as woodlands or mountains where the load-bearing frame needs to be raised, the lifting device can be used to drive the load-bearing frame up and down as needed, adjusting its height to adapt to the terrain.

[0009] Optionally, the sliding structure includes:

[0010] The sliding joint is connected to both the first side beam and the second side beam. The sliding joint has a groove from top to bottom. The slider is slidably disposed in the groove and can slide up and down along the groove.

[0011] Beneficial effects: The sliders on both sides of the load-bearing frame are slidably inserted into the grooves on the sliding joints of the first and second side beams, respectively. With a relatively simple structure, the sliders on both sides of the load-bearing frame can slide in the grooves to provide effective guidance for the lifting and lowering of the load-bearing frame.

[0012] Optionally, the slider is connected to the load-bearing frame via a connecting block, and the sliding joint is provided with a through groove communicating with the slide groove, and the connecting block is slidably disposed in the through groove.

[0013] Beneficial effects: The slider is slidably inserted into the slide groove, while the connecting block is slidably inserted into the through groove. When the slider slides up and down along the extension direction of the slide groove, the connecting block slides synchronously along the extension direction of the through groove. Thus, the slider and the connecting block together provide guidance for the lifting and lowering of the load-bearing frame, making the guidance more reliable.

[0014] Optionally, the width of the slider is greater than the width of the through slot.

[0015] Beneficial effect: After the slider is slidably inserted into the groove, since the width of the slider is greater than the width of the groove, the slider cannot detach from the groove laterally, thus preventing the slider from sliding out of the groove and losing its guiding effect.

[0016] Optionally, the sliding structure further includes:

[0017] A housing, which is sleeved around the sliding joint;

[0018] A connector is used to connect the inner wall of the housing and the outer wall of the sliding joint.

[0019] Beneficial effects: The connector is connected between the inner wall of the housing and the outer wall of the sliding joint. The housing reinforces the sliding joint through the connector, increasing the bending resistance of the sliding joint.

[0020] Optionally, at least two connectors are provided along the circumference of the sliding joint, and the two connectors are arranged opposite each other and respectively on both sides of the sliding joint.

[0021] Beneficial effect: The two connectors abut against the sliding joint in opposite directions on the same straight line, which further increases the bending resistance of the sliding joint.

[0022] Optionally, the connector includes:

[0023] An elastic element is connected to one of the inner wall of the housing and the outer wall of the sliding joint.

[0024] The abutting part is connected to the elastic member, and the abutting part is connected to one of the inner wall of the housing and the outer wall of the sliding part.

[0025] Beneficial effects: Under the elastic force of the elastic element, the abutting part presses against the outer wall of the sliding part to resist the lateral force on the sliding part, preventing large deformation of the sliding part and increasing its bending resistance. At the same time, under the deformation of the elastic element, the lateral force is eliminated, avoiding damage to the sliding part caused by rigid confrontation.

[0026] Optionally, the sliding joint is provided with a through hole communicating with the sliding groove, and the abutting part is provided with a spherical surface suitable for passing through the through hole.

[0027] Beneficial effects: When the slider slides up and down along the groove, when it reaches the through hole, it pushes the spherical portion that has entered the groove back into the through hole, at which point the elastic element is compressed. When the slider leaves the through hole, the spherical portion re-enters the groove from the through hole due to the rebound action of the elastic element. The lateral force generated by inertia during slider movement can be partially offset by the elastic element, reducing the lateral force on the sliding joint and preventing damage to the sliding joint.

[0028] Optionally, the lifting device includes a piston cylinder, and the piston cylinder is provided on both the first side beam and the second side beam. A support part is provided on both the first side and the second side of the load frame. The movable part of the piston cylinder is connected to the bottom of the support part. The movable part of the piston cylinder can lift or lower the support part by moving.

[0029] Beneficial effects: Using a piston cylinder as a lifting device, the piston rod extends to lift the load frame, and retracts to lower the load frame. The structure is simple and reliable.

[0030] Secondly, this application also provides an engineering machine, including any of the aforementioned underframes. The beneficial effects of this engineering machine are the same as those of the underframe, and therefore will not be described in detail. Attached Figure Description

[0031] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 This is a schematic diagram of the structure of a lower frame according to an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the structure of the first side beam of a lower frame according to an embodiment of this application;

[0034] Figure 3 This is a schematic diagram of the structure of the second side beam of a lower frame according to an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of a sliding structure of a lower frame according to an embodiment of this application;

[0036] Figure 5 This is a schematic diagram of the sliding joint structure of a lower frame according to an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of the shell structure of a sliding structure of a lower frame according to an embodiment of this application;

[0038] Figure 7 This is a schematic diagram of the connecting component structure of a sliding joint structure of a lower frame according to an embodiment of this application;

[0039] Figure 8 This is a schematic diagram illustrating the connection between an extension plate of the underframe and a piston cylinder according to an embodiment of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. First side beam; 2. Second side beam; 3. Load-bearing frame; 4. Sliding block; 5. Connecting block; 6. Sliding joint structure; 61. Sliding joint part; 62. Housing; 63. Connecting piece; 631. Elastic element; 632. Abutment part; 64. Cover; 7. Slide groove; 8. Through groove; 9. Extension plate; 10. Sleeve; 11. Spherical part; 12. Through hole; 13. Piston cylinder. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] The following is combined Figures 1 to 7 This describes an embodiment of the present application.

[0044] According to embodiments of this application, in one aspect, a lower frame is provided, such as... Figures 1 to 3 As shown, the system includes: a first side beam 1, a load-bearing frame 3, a second side beam 2, and a lifting device. Sliding blocks 4 are connected to both the first and second sides of the load-bearing frame 3, allowing the load-bearing frame 3 to move synchronously with the sliding blocks 4 on both sides. Sliding structures 6 are connected to both the first side beam 1 and the second side beam 2. The sliding block 4 on the first side of the load-bearing frame 3 is slidably connected to the sliding structure 6 on the first side beam 1, allowing the sliding block 4 on the first side of the load-bearing frame 3 to slide up and down relative to the sliding structure 6 on the first side beam 1. The sliding block 4 on the second side of the load-bearing frame 3 is slidably connected to the sliding structure 6 on the second side beam 2, allowing the sliding block 4 on the second side of the load-bearing frame 3 to slide up and down relative to the sliding structure 6 on the second side beam 2. When the sliding blocks 4 on both sides of the load-bearing frame 3 slide up and down, the load-bearing frame 3 moves up and down relative to the first side beam 1 and the second side beam 2.

[0045] Lifting devices are provided on both the first side beam 1 and the second side beam 2. The lifting devices are connected to the load frame 3 and can extend to lift the load frame 3 to move upward and retract to lower the load frame 3 to move downward.

[0046] The first side beam 1 and the second side beam 2 are respectively connected to the traveling mechanisms on both sides, while the working mechanism for construction is connected to the load-bearing frame 3. When it is necessary to raise the load-bearing frame 3, the lifting device extends upward to lift the load-bearing frame 3, causing it to move upward. At this time, the slider 4 on the first side of the load-bearing frame 3 slides upward relative to the sliding structure 6 on the first side beam 1, and the slider 4 on the second side of the load-bearing frame 3 slides upward relative to the sliding structure 6 on the second side beam 2, guiding the rise of the load-bearing frame 3. When the load-bearing frame 3 rises to the required position, the lifting device stops extending, at which point the lifting device serves to support the load-bearing frame 3.

[0047] When it is necessary to lower the load frame 3, the lifting device is retracted downwards. Under its own weight, the load frame 3 moves downwards as the lifting device retracts. At this time, the slider 4 on the first side of the load frame 3 slides upwards relative to the sliding structure 6 on the first side beam 1, and the slider 4 on the second side of the load frame 3 slides upwards relative to the sliding structure 6 on the second side beam 2, guiding the load frame 3 as it rises. When the load frame 3 has descended to the required lowering position, the lifting device stops retracting, at which point the lifting device serves to support the load frame 3.

[0048] With this configuration, guided by the relative up-and-down sliding between the slider 4 and the sliding joint structure 6, the lifting device can drive the load-bearing frame 3 to move up and down relative to the first side beam 1 and the second side beam 2. For terrains such as woodlands or mountains where the height of the load-bearing frame 3 needs to be raised, the lifting device can be used to drive the load-bearing frame 3 up and down as needed to adjust its height to adapt to the terrain.

[0049] The lifting device can be a piston cylinder structure such as a pneumatic cylinder or a hydraulic cylinder, or it can be a common displacement device such as an electric rod or a lead screw device.

[0050] Regarding the arrangement of the sliders 4, at least two sliders 4 are respectively provided on the first and second sides of the load-bearing frame 3. When two sliders 4 are provided on each side, the four sliders 4 are located at the four corners of the load-bearing frame 3. Correspondingly, at least two sliding structures 6 are respectively provided on the first side beam 1 and the second side beam 2, and the sliding structures 6 correspond one-to-one with the sliders 4.

[0051] For the setting of the lifting device, at least two lifting devices are respectively set on the first side beam 1 and the second side beam 2. The lifting device can correspond one-to-one with the sliding structure 6 and be set on one side of the corresponding sliding structure 6.

[0052] In other embodiments, two sliders 4 are provided on the first side of the load-bearing frame 3, with the two sliders 4 located at two corners respectively. Two sliding structures 6 are provided on the first side beam 1, with each sliding structure 6 corresponding to one of the sliders 4. Two lifting devices are provided on the first side beam 1, with each lifting device corresponding to one of the sliding structures 6.

[0053] A slider 4 is installed on the second side of the load-bearing frame 3, and a sliding structure 6 is installed on the second side beam 2, corresponding to the slider 4. A lifting device is installed on the second side beam 2, corresponding to the sliding structure 6.

[0054] Alternatively, two sliders 4 are provided on the second side of the load-bearing frame 3, with the two sliders 4 located at two corners respectively. Two sliding joint structures 6 are provided on the second side beam 2, with each sliding joint structure 6 corresponding to one of the sliders 4. Two lifting devices are provided on the second side beam 2, with each lifting device corresponding to one of the sliding joint structures 6.

[0055] A slider 4 is provided on the first side of the load-bearing frame 3, and a sliding structure 6 is provided on the first side beam 1, corresponding to the slider 4. A lifting device is provided on the first side beam 1, corresponding to the sliding structure 6.

[0056] In one embodiment, such as Figure 4 As shown, the sliding structure 6 includes a sliding part 61. Sliding parts 61 are connected to both the first side beam 1 and the second side beam 2. The bottom of the sliding part 61 is fixedly connected to the top surface of either the first side beam 1 or the second side beam 2; it can be welded or integrally connected. A groove 7 is formed from top to bottom on the top surface of the sliding part 61. The slider 4 on the first side of the load-bearing frame 3 is inserted into the groove 7 on the sliding part 61 of the first side beam 1, allowing it to slide up and down along the groove 7. The slider 4 on the second side of the load-bearing frame 3 is inserted into the groove 7 on the sliding part 61 of the second side beam 2, allowing it to slide up and down along the groove 7. This relatively simple structure provides effective guidance for the lifting and lowering of the load-bearing frame 3 when the sliders 4 on both sides of the load-bearing frame 3 slide within their respective grooves 7.

[0057] In a further embodiment, Figures 1 to 4 As shown, the lower frame also includes a connecting block 5. The first end of the connecting block 5 is connected to the load frame 3, and the second end is connected to the slider 4, thus connecting the slider 4 to the load frame 3 via the connecting block 5. A through groove 8 is formed from top to bottom on the top surface of the sliding joint 61, communicating with the slide groove 7. While the slider 4 is slidably inserted into the slide groove 7, the connecting block 5 is slidably inserted into the through groove 8. When the slider 4 slides up and down along the extension direction of the slide groove 7, the connecting block 5 simultaneously slides along the extension direction of the through groove 8. Thus, the synchronous sliding of the slider 4 and the connecting block 5 provides guidance for the lifting and lowering of the load frame 3, making the guidance more reliable.

[0058] After the slider 4 and the connecting block 5 are respectively inserted into the slide groove 7 and the through groove 8, a cover 64 is provided on the top of the sliding joint 61. The cover 64 can close the top openings of the through groove 8 and the slide groove 7, preventing the slider 4 from sliding out of the top opening of the slide groove 7 and preventing the connecting block 5 from sliding out of the top opening of the through groove 8.

[0059] In a further embodiment, such as Figure 4 As shown, the width of slider 4 is greater than the width of through groove 8. With this setting, after slider 4 is slidably inserted into through groove 7, since the width of slider 4 is greater than the width of through groove 8, slider 4 cannot detach laterally from through groove 7, thus preventing slider 4 from sliding out of through groove 7 and losing its guiding effect.

[0060] In one embodiment, such as Figures 4 to 6 As shown, the sliding joint structure 6 also includes a housing 62 and a connector 63. The housing 62 is fitted around the sliding joint portion 61, and its bottom is fixedly connected to the top surface of the first side beam 1 or the second side beam 2; it can be welded or integrally joined. The first end of the connector 63 is connected to the inner wall of the housing 62, and the second end is connected to the outer wall of the sliding joint portion 61. Thus, the connector 63 connects the inner wall of the housing 62 and the outer wall of the sliding joint portion 61, providing reinforcement to the sliding joint portion 61 through the connector 63 and increasing its bending resistance.

[0061] The connector 63 can be configured as a connecting rod or connecting arm with a certain rigidity, connecting the outer wall of the sliding part 61 and the inner wall of the housing 62, so as to support the sliding part 61 between the outer wall of the sliding part 61 and the inner wall of the housing 62 and increase the bending resistance of the sliding part 61.

[0062] In optional embodiments, such as Figure 4 As shown, at least two connectors 63 are provided along the circumference of the sliding joint 61, with the two connectors 63 arranged opposite each other. The two connectors 63 are respectively arranged on both sides of the sliding joint 61, that is, the two connectors 63 abut against the sliding joint 61 in opposite directions on the same straight line, which further increases the bending resistance of the sliding joint 61.

[0063] Three connectors 63 can also be provided along the circumference of the sliding joint 61. In addition to the two connectors 63 arranged opposite to each other, the direction of action of the other connector 63 on the sliding joint 61 is perpendicular to the direction of action of the two opposite connectors 63 on the sliding joint 61, further increasing the bending resistance of the sliding joint 61.

[0064] Furthermore, multiple connectors 63 can be provided on the same side of the sliding joint 61, with the multiple connectors 63 arranged sequentially from top to bottom, so that the multiple connectors 63 provide support for the sliding joint 61 on the same side.

[0065] In optional embodiments, such as Figures 4 to 7As shown, the connector 63 includes an elastic element 631 and an abutment portion 632 connected to each other. The elastic element 631 is connected to the inner wall of the housing 62, and the elastic element 631 can be a spring. When the elastic element 631 is compressed, the abutment portion 632 abuts against the outer wall of the sliding joint 61 under the elastic force of the elastic element 631. When the working mechanism on the load-bearing frame 3 is performing construction work, the load-bearing frame 3 is subjected to a certain lateral force due to inertia. This lateral force is transmitted to the sliding joint 61 through the slider 4, causing the sliding joint 61 to tend to deform. At this time, under the elastic force of the elastic element 631, the abutment portion 632 abuts against the outer wall of the sliding joint 61 to resist this lateral force, preventing the sliding joint 61 from undergoing large deformation and increasing the bending resistance of the sliding joint 61. Simultaneously, under the deformation of the elastic element 631, the lateral force is eliminated, preventing damage to the sliding joint 61 due to rigid resistance.

[0066] In another embodiment, the elastic member 631 can be connected to the outer wall of the sliding part 61, and correspondingly, the abutting part 632 abuts against the inner wall of the housing 62.

[0067] In optional embodiments, such as Figures 4 to 7 As shown, the elastic element 631 is connected to the inner wall of the housing 62. Under the elastic force of the elastic element 631, the abutting part 632 abuts against the outer wall of the sliding part 61. The sliding part 61 is provided with a circular through hole 12, which communicates with the sliding groove 7. A spherical part 11 is provided on the side of the abutting part 632 away from the elastic element 631. When the abutting part 632 abuts against the outer wall of the sliding part 61, a portion of the spherical part 11 on the abutting part 632 passes through the through hole 12 and enters the sliding groove 7.

[0068] With this configuration, when the slider 4 slides up and down along the groove 7, when it reaches the through hole 12, it can push the portion of the spherical part 11 that has entered the groove 7 through the through hole 12 back into the through hole 12, at which point the elastic element 631 is compressed. When the slider 4 leaves the through hole 12, under the rebound action of the elastic element 631, the portion of the spherical part 11 enters the groove 7 from the through hole 12. This allows the elastic element 631 to partially offset the lateral force generated by inertia when the slider 4 slides, reducing the lateral force on the sliding joint 61, preventing damage to the sliding joint 61, and reducing the wobbling of the slider 4, thus increasing the stability of the slider 4 during its up and down movement.

[0069] In one embodiment, Figures 2 to 4As shown, the lifting device includes a piston cylinder 13, which is a hydraulic cylinder. Piston cylinders 13 are installed on both the first side beam 1 and the second side beam 2. The cylinder body of the piston cylinder 13 is a fixed part and is fixedly installed on the first side beam 1 or the second side beam 2. The piston cylinder 13 is vertically arranged, and the piston rod of the piston cylinder 13 is a movable part that moves up and down during extension and retraction. Support parts are provided on both the first and second sides of the load-bearing frame 3, wherein the support parts can be extension plates 9 connected to the first or second side of the load-bearing frame 3.

[0070] The extension plate 9 on the first side of the load frame 3 is placed on the top of the piston rod of the piston cylinder 13 on the first side beam 1, and the extension plate 9 on the second side of the load frame 3 is placed on the top of the piston rod of the piston cylinder 13 on the second side beam 2.

[0071] In this way, when the piston rods of the piston cylinders 13 on the first side beam 1 and the second side beam 2 extend synchronously and move upward, they push the support parts on the first and second sides of the load frame 3 upward, causing the load frame 3 to rise. When the load frame 3 rises to the required position, the piston rod of the piston cylinder 13 stops extending, and at this time, the piston cylinder 13 plays the role of supporting the load frame 3.

[0072] When the piston rods of the piston cylinders 13 on the first side beam 1 and the second side beam 2 retract synchronously and move downward, the support parts on the first and second sides of the load frame 3 descend with the piston rods under their own weight, and the load frame 3 descends. When the load frame 3 descends to the required lowering position, the piston rod of the piston cylinder 13 stops retracting, and at this time the piston cylinder 13 plays the role of supporting the load frame 3.

[0073] With this configuration, using piston cylinder 13 as a lifting device, the extension of the piston rod lifts the load frame 3, and the retraction of the piston rod lowers the load frame 3. The structure is simple and reliable.

[0074] In optional embodiments, such as Figure 8 As shown, a sleeve 10 is provided at the bottom of the extension plate 9. When the extension plate 9 is placed on top of the piston rod of the piston cylinder 13, the piston rod is inserted into the sleeve 10 and abuts against the bottom of the extension plate 9. With this arrangement, when the piston rod of the piston cylinder 13 extends or retracts, the piston rod remains in the sleeve 10 and abuts against the bottom of the extension plate 9, preventing the piston rod from disengaging from the bottom of the extension plate 9.

[0075] According to an embodiment of this application, another aspect provides an engineering machine including any of the aforementioned underframes. The beneficial effects of this engineering machine are the same as those of the underframe, and therefore will not be described in detail.

[0076] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by this application.

Claims

1. A chassis frame, characterized in that, include: The first side beam (1), the load-bearing frame (3), the second side beam (2), and the lifting device, wherein, The load-bearing frame (3) is provided with sliders (4) on both the first and second sides. The first side beam (1) and the second side beam (2) are provided with sliding structures (6). The slider (4) on the first side of the load-bearing frame (3) is slidably connected to the sliding structure (6) on the first side beam (1) and can slide up and down. The slider (4) on the second side of the load-bearing frame (3) is slidably connected to the sliding structure (6) on the second side beam (2) and can slide up and down. The lifting device is provided on both the first side beam (1) and the second side beam (2), and the lifting device is adapted to lift or lower the load frame (3).

2. The underframe according to claim 1, characterized in that, The sliding structure (6) includes: The sliding joint (61) is connected to both the first side beam (1) and the second side beam (2). The sliding joint (61) is provided with a sliding groove (7) from top to bottom. The slider (4) is slidably disposed in the sliding groove (7) and can slide up and down along the sliding groove (7).

3. The underframe according to claim 2, characterized in that, The slider (4) is connected to the load frame (3) via the connecting block (5). The sliding joint (61) is provided with a through groove (8) that communicates with the sliding groove (7). The connecting block (5) is slidably disposed in the through groove (8).

4. The underframe according to claim 3, characterized in that, The width of the slider (4) is greater than the width of the through groove (8).

5. The underframe according to claim 2, characterized in that, The sliding structure (6) also includes: A housing (62) is fitted around the sliding joint (61); A connector (63) is connected between the inner wall of the housing (62) and the outer wall of the sliding part (61).

6. The underframe according to claim 5, characterized in that, At least two connectors (63) are provided along the circumference of the sliding part (61), and the two connectors (63) are arranged opposite each other and respectively on both sides of the sliding part (61).

7. The underframe according to claim 5, characterized in that, The connector (63) includes: The elastic element (631) is connected to one of the inner wall of the housing (62) and the outer wall of the sliding part (61); The abutting part (632) is connected to the elastic member (631), and the abutting part (632) is connected to one of the inner wall of the housing (62) and the outer wall of the sliding part (61).

8. The underframe according to claim 7, characterized in that, The sliding part (61) is provided with a through hole (12) communicating with the sliding groove (7), and the abutting part (632) is provided with a spherical part (11) suitable for passing through the through hole (12).

9. The underframe according to claim 1, characterized in that, The lifting device includes a piston cylinder (13), and the piston cylinder (13) is provided on both the first side beam (1) and the second side beam (2). The first and second sides of the load frame (3) are provided with support parts. The movable part of the piston cylinder (13) is connected to the bottom of the support part. The movable part of the piston cylinder (13) can lift or lower the support part by moving.

10. An engineering machinery, characterized in that, include: The underframe as described in any one of claims 1-9.

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