A type of electrically assisted two-stage hydraulic cylinder

Abstract

This application provides an electrically assisted two-stage hydraulic cylinder, relating to the technical field of hydraulic cylinders. It includes a first cylinder and a second cylinder. The piston rod end of the first cylinder is fixed to the outer wall of the second cylinder via a connecting block. Racks are fixed to opposite sides of the cylinder bodies of both cylinders, and a gear meshes between the two racks. A slide block is slidably connected to the outer wall of the first cylinder, and the gear is rotatably connected to the slide block. A motor is fixed to the slide block, and the output end of the motor is connected to the gear transmission via a reducer. The reducer includes a meshing worm gear and a worm shaft. The worm shaft serves as the input shaft and is fixed to the output end of the motor. An output sleeve is coaxially fixed to the worm gear. This application transmits the power output from the motor to the second cylinder through the meshing of the gear and rack, working in conjunction with hydraulic pressure to increase the total extension force of the two-stage hydraulic cylinder without increasing the burden on the hydraulic system and sealing components. It also allows for free switching between using electric assistance and other methods.

Description

Technical Field

[0001] This application relates to the field of hydraulic cylinder technology, and in particular to an electrically assisted two-stage hydraulic cylinder. Background Technology

[0002] The hydraulic cylinder is driven by a hydraulic pump. Utilizing the reliable sealing of the hydraulic system and the extremely low compressibility of hydraulic oil, the cylinder extends and retracts through hydraulic pressure, generating significant thrust. It is widely used in engineering machinery, industrial production, and construction.

[0003] Patent application CN121800078A discloses a six-section crane boom system with dual cylinders and external ropes for controllable telescopic extension and retraction. The system includes: a basic boom, a second boom, a third boom, a fourth boom, a fifth boom, a sixth boom, a first telescopic cylinder, a second telescopic cylinder, and a control rope assembly. The basic boom, second boom, third boom, fourth boom, fifth boom, and sixth boom are connected sequentially from the outside in via nested nylon sliders. The piston rod head of the first telescopic cylinder is hinged to the tail of the basic boom, and the cylinder barrel is hinged to the tail of the second boom to achieve the extension and retraction of the second boom. The piston rod head of the second telescopic cylinder is hinged to the cylinder barrel of the first telescopic cylinder, and the cylinder barrel is hinged to the tail of the third boom, used to drive the synchronous extension and retraction of the third, fourth, fifth, and sixth booms via the control rope assembly.

[0004] The aforementioned technologies form a two-stage telescopic system by connecting two independent hydraulic cylinders. As technology advances, the performance requirements for hydraulic cylinders are becoming increasingly stringent. To further increase the thrust of the hydraulic cylinder, increasing the oil pressure is one approach, but this would increase the burden on the hydraulic system, increase the pressure on the sealing components, and pose risks of leakage and explosion. Summary of the Invention

[0005] This application provides an electrically assisted two-stage hydraulic cylinder that increases the total thrust of the two-stage cylinder through electric assistance without increasing the burden on the hydraulic system and sealing components.

[0006] This application provides an electrically assisted two-stage hydraulic cylinder, which adopts the following technical solution: An electrically assisted two-stage hydraulic cylinder includes a first cylinder and a second cylinder. The piston rod end of the first cylinder is fixed to the outer wall of the cylinder body of the second cylinder via a connecting block. Racks are fixed on opposite sides of the cylinder bodies of the first and second cylinders, and a gear meshes between the two racks. A slide block is slidably connected to the outer wall of the first cylinder, and the gear is rotatably connected to the slide block. A motor is fixed on the slide block, and the output end of the motor is connected to the gear transmission via a reducer.

[0007] By adopting the above technical solution, when the motor is started, the motor drives the gear to rotate through the reducer. The gear meshes with the upper and lower racks, and the rotation of the gear moves the cylinder body of the second cylinder forward. At the same time, the gear rolls forward along the outer wall of the first cylinder, causing the slide to move axially along the first cylinder. In this way, the power output by the motor is transmitted to the second cylinder, which, together with the hydraulic pressure, increases the total force of the two-stage cylinder extension.

[0008] Optionally, the reducer includes a meshing worm gear and a worm, the worm being fixed to the output end of the motor as an input shaft, an output sleeve being fixed coaxially to the worm gear, a spline shaft being fixed to the end of the gear, and a spline sleeve being slidably connected inside the output sleeve via a keyway, the structure of the spline sleeve being adapted to the spline shaft.

[0009] By adopting the above technical solution, the reduction mechanism formed by the worm gear and worm has a large reduction ratio, allowing the motor to output greater torque at the same power. Reverse transmission is avoided by sliding the spline sleeve away from the spline shaft.

[0010] Optionally, a telescopic cylinder is installed inside the output sleeve. The piston rod end of the telescopic cylinder is rotatably connected to the spline sleeve through a bearing. A spring is provided between the spline sleeve and the output sleeve. The elastic force of the spring drives the spline sleeve to separate from the spline shaft.

[0011] By adopting the above technical solution, when the telescopic cylinder extends, it drives the spline sleeve to engage with the spline shaft, thereby realizing transmission. When the telescopic cylinder shortens or depressurizes, the spring force drives the spline sleeve to separate from the spline shaft, serving as the restoring force for the spline sleeve to retract.

[0012] Optionally, the telescopic cylinder is a hydraulic cylinder, and an oil pipe joint is rotatably connected to the end of the output sleeve. The inner end of the oil pipe joint is connected to the inside of the telescopic cylinder, and the outer end of the oil pipe joint is connected to a bypass pipe. The other end of the bypass pipe is connected to the oil inlet pipe of the first cylinder.

[0013] By adopting the above technical solution, the extension and retraction of the telescopic cylinder are linked to the pressure in the oil inlet pipe of cylinder one, thereby realizing the automatic operation of the telescopic cylinder.

[0014] Optionally, an electrically controlled valve is installed on the bypass pipe.

[0015] By adopting the above technical solution, the oil can be controlled to enter and exit the telescopic cylinder through an electronically controlled valve.

[0016] Optionally, the spline end of the spline shaft is chamfered, so that the width of the spline end is gradually narrowed.

[0017] By adopting the above technical solution, the splined shaft and splined sleeve are easier to insert when they are connected by chamfering.

[0018] Optionally, the bottom surface of the slide block is rotatably connected to multiple ball bearings via multiple ball grooves, and the ball bearings make rolling contact with the outer wall of the hydraulic cylinder.

[0019] By adopting the above technical solution, the wear and frictional resistance of the slide block are reduced by using ball bearings.

[0020] Optionally, two baffles are symmetrically fixed at the tail end of the second hydraulic cylinder, and the two baffles are respectively set close to the opposite side walls of the first hydraulic cylinder.

[0021] By adopting the above technical solution, two baffles are used to limit the left and right sides of the first cylinder, thus preventing the first and second cylinders from tilting.

[0022] Optionally, a stop wheel is rotatably connected to the side of the second hydraulic cylinder opposite to the first hydraulic cylinder.

[0023] By adopting the above technical solution, the abutment wheel is used to form a guiding effect by rolling contact with the external structure, so that the axes of cylinder 2 and cylinder 1 always remain parallel and the distance between them remains unchanged.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. Through the meshing of gears and racks, the power output from the motor is transmitted to the second hydraulic cylinder, which works together with hydraulic pressure to increase the total force of the two-stage hydraulic cylinder extension; 2. It will not increase the burden on the hydraulic system and sealing components; 3. The electric assist function can be freely switched on and off. Switching to electric assist is simple and easy to control. Attached Figure Description

[0025] Figure 1 This is a perspective view of an electrically assisted two-stage hydraulic cylinder according to an embodiment; Figure 2 This is a partial enlarged view of the front of the embodiment; Figure 3 This is a schematic diagram of the left side of an embodiment; Figure 4 This is a partial three-dimensional view of the embodiment.

[0026] Explanation of reference numerals in the attached drawings: 1. Hydraulic cylinder one; 10. Rack; 11. Connecting block; 2. Hydraulic cylinder two; 21. Baffle; 22. Abutment wheel; 3. Gear; 31. Splined shaft; 4. Slide; 41. Motor; 42. Reducer; 43. Ball bearing; 44. Worm gear; 45. Worm; 5. Output sleeve; 51. Splined sleeve; 52. Telescopic cylinder; 53. Spring; 54. Oil pipe joint; 6. Bypass pipe; 61. Electrically controlled valve. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the accompanying drawings.

[0028] Reference Figure 1 This embodiment discloses an electrically assisted two-stage hydraulic cylinder, including a first cylinder 1 and a second cylinder 2. The second cylinder 2 is located above the first cylinder 1. The first cylinder 1 and the second cylinder 2 are close to each other and arranged in parallel. The piston rod end of the first cylinder 1 is fixed to the outer wall of the cylinder body of the second cylinder 2 through a connecting block 11.

[0029] Two baffles 21 are symmetrically fixed to the tail end of cylinder 2. These baffles 21 are positioned close to the opposite side walls of cylinder 1, limiting the left and right sides of cylinder 1 and preventing misalignment between cylinder 1 and cylinder 2. A stop wheel 22 is rotatably connected to the side of cylinder 2 away from cylinder 1. The stop wheel 22 provides a guiding effect through rolling contact with the external structure, ensuring that the axes of cylinder 2 and cylinder 1 remain parallel and the distance between them remains constant. If this double-stage cylinder is built into the boom, the stop wheel 22 contacts one of the inner walls of the boom stage; if it is externally mounted, the stop wheel 22 contacts the frame or track. During use, considering the weight of cylinder 2, the distance between cylinder 1 and cylinder 2 will not increase.

[0030] Reference Figure 1 and Figure 2 Both hydraulic cylinders 1 and 2 have racks 10 fixed to opposite sides of their cylinder bodies. A gear 3 meshes between the two racks 10, keeping the gear 3 clamped and always engaged with the racks 10. During installation, ensure that hydraulic cylinder 2 is positioned above hydraulic cylinder 1; the weight of hydraulic cylinder 2 also helps to clamp the gear 3. A slide block 4 is slidably connected to the outer wall of hydraulic cylinder 1. The gear 3 is rotatably connected to the slide block 4, and a motor 41 is fixed to the slide block 4. The output of the motor 41 is connected to the gear 3 via a reducer 42. The motor 41 has a built-in protection function, automatically cutting off the power when the resistance is too high.

[0031] Reference Figure 3 and Figure 4 The bottom surface of the slide block 4 is rotatably connected to multiple ball bearings 43 via multiple ball grooves. The ball bearings 43 roll in contact with the outer wall of the first cylinder 1, reducing wear and frictional resistance. The upper part of the slide block 4 extends to both sides of the outer wall of the second cylinder 2, where the ball bearings 43 also roll in contact with the outer wall of the second cylinder 2, thereby stabilizing the slide block 4 in the corresponding position and improving the sliding stability of the slide block 4.

[0032] The reducer 42 includes a meshing worm gear 44 and a worm 45. The worm 45 serves as the input shaft and is fixed to the output end of the motor 41. An output sleeve 5 is coaxially fixed to the worm gear 44, serving as the output end of the reducer 42. A splined shaft 31 is fixed to the end of the gear 3. A splined sleeve 51 is slidably connected to the output sleeve 5 via a keyway. The splined sleeve 51 faces the splined shaft 31, and its structure is adapted to the splined shaft 31. The splined sleeve 51 can switch between two states—engaged and disengaged—by sliding with the splined shaft 31. Through the reduction mechanism formed by the worm gear 44 and the worm 45, the reduction ratio is large, allowing the motor 41 to output greater torque at the same power. The splined end of the splined shaft 31 has a chamfer, making the splined end width gradually narrow, making it easier to insert the splined shaft 31 into the splined sleeve 51.

[0033] To achieve automatic movement of the spline sleeve 51, a telescopic cylinder 52 is installed inside the output sleeve 5. The telescopic cylinder 52 does not rotate with the output sleeve 5. The piston rod end of the telescopic cylinder 52 is rotatably connected to the spline sleeve 51 via a bearing. Both the inner and outer walls of the bearing are interference fits, so there is no axial relative movement between the piston rod end of the telescopic cylinder 52 and the spline sleeve 51. A spring 53 is provided between the spline sleeve 51 and the output sleeve 5. The two ends of the spring 53 are fixed to the spline sleeve 51 and the output sleeve 5, respectively. The spring 53 is always in a stretched state. The elastic force of the spring 53 drives the spline sleeve 51 to separate from the spline shaft 31, serving as the restoring force for the retraction of the spline sleeve 51.

[0034] The telescopic cylinder 52 can be any automatic cylinder, such as a hydraulic cylinder, electric cylinder or pneumatic cylinder. When the telescopic cylinder 52 is extended in a controlled manner, it can push the spline sleeve 51 to move and engage with the spline shaft 31, thereby realizing transmission. At this time, the motor 41 is started, and torque is output to the gear 3. The gear 3, through meshing with the two racks 10, pushes the second oil cylinder 2 to move forward.

[0035] In this embodiment, the telescopic cylinder 52 is a hydraulic cylinder, and it is the simplest hydraulic cylinder structure with a single-channel inlet and outlet. An oil pipe connector 54 is rotatably connected to the end of the output sleeve 5. The inner end of the oil pipe connector 54 is connected to the inside of the telescopic cylinder 52, and the outer end of the oil pipe connector 54 is connected to a bypass pipe 6. The other end of the bypass pipe 6 is connected to the oil inlet pipe of the cylinder 1. An electric control valve 61 is installed on the bypass pipe 6, which controls whether oil can enter and exit the telescopic cylinder 52.

[0036] The implementation principle of an electrically assisted two-stage hydraulic cylinder according to an embodiment of this application is as follows: when electric assistance is not required, the electric control valve 61 is in the closed state, at which time the telescopic cylinder 52 is in the shortened state, the spline sleeve 51 is separated from the spline shaft 31, and the extension and retraction of cylinder 1 and cylinder 2 are controlled by a conventional hydraulic system.

[0037] When electric assistance is required, the electric control valve 61 and motor 41 are activated, causing the spline sleeve 51 to rotate. Oil in the inlet pipe enters the telescopic cylinder 52 through the bypass pipe 6. Since electric assistance is only required during the extension phase of cylinder 1, the oil pressure in the inlet pipe is relatively high, ensuring reliable extension of the telescopic cylinder 52. This allows the spline sleeve 51 to engage with the spline shaft 31. The rotation of the spline sleeve 51 is transmitted to the gear 3 via the spline shaft 31. The gear 3 meshes with the upper and lower racks 10, causing the cylinder body of cylinder 2 to move forward. Simultaneously, the gear 3 rolls forward along the outer wall of cylinder 1, driving the slide 4 to move axially along cylinder 1. This transmits the power output from motor 41 to cylinder 2, working in conjunction with hydraulic pressure to increase the total extension force of the two-stage cylinder.

[0038] When it is necessary to shorten cylinder 1, motor 41 is turned off. When cylinder 1 is in the retraction phase, the oil pressure in the inlet pipe drops significantly. Therefore, under the action of spring 53, telescopic cylinder 52 shortens, and the hydraulic oil in telescopic cylinder 52 flows back to bypass pipe 6. Spline sleeve 51 separates from spline shaft 31, thereby avoiding reverse transmission. This realizes the automatic operation of telescopic cylinder 52 and the automatic engagement and disengagement of spline sleeve 51 and spline shaft 31.

[0039] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An electrically assisted two-stage hydraulic cylinder, comprising a first cylinder (1) and a second cylinder (2), wherein the piston rod end of the first cylinder (1) is fixed to the outer wall of the cylinder body of the second cylinder (2) by a connecting block (11), characterized in that: The cylinder bodies of the first cylinder (1) and the second cylinder (2) are respectively fixed with racks (10) on opposite sides. The two racks (10) are meshed with a gear (3). The outer wall of the first cylinder (1) is slidably connected to a slide block (4). The gear (3) is rotatably connected to the slide block (4). The slide block (4) is fixed with a motor (41). The output end of the motor (41) is connected to the gear (3) through a reducer (42).

2. The electrically assisted two-stage hydraulic cylinder according to claim 1, characterized in that: The reducer (42) includes a worm gear (44) and a worm (45) meshing together. The worm (45) is fixed to the output end of the motor (41) as an input shaft. The worm gear (44) is coaxially fixed with an output sleeve (5). The end of the gear (3) is fixed with a spline shaft (31). A spline sleeve (51) is slidably connected inside the output sleeve (5) through a keyway. The structure of the spline sleeve (51) is adapted to the spline shaft (31).

3. The electrically assisted two-stage hydraulic cylinder according to claim 2, characterized in that: A telescopic cylinder (52) is installed inside the output sleeve (5). The piston rod end of the telescopic cylinder (52) is rotatably connected to the spline sleeve (51) through a bearing. A spring (53) is provided between the spline sleeve (51) and the output sleeve (5). The elastic force of the spring (53) drives the spline sleeve (51) to separate from the spline shaft (31).

4. The electrically assisted two-stage hydraulic cylinder according to claim 3, characterized in that: The telescopic cylinder (52) is a hydraulic cylinder. The end of the output sleeve (5) is rotatably connected to an oil pipe joint (54). The inner end of the oil pipe joint (54) is connected to the inside of the telescopic cylinder (52). The outer end of the oil pipe joint (54) is connected to a bypass pipe (6). The other end of the bypass pipe (6) is connected to the oil inlet pipe of the first oil cylinder (1).

5. The electrically assisted two-stage hydraulic cylinder according to claim 4, characterized in that: An electrically controlled valve (61) is installed on the bypass pipe (6).

6. The electrically assisted two-stage hydraulic cylinder according to claim 2, characterized in that: The spline end of the spline shaft (31) is chamfered, so that the width of the spline end is gradually reduced.

7. The electrically assisted two-stage hydraulic cylinder according to claim 1, characterized in that: The bottom surface of the slide (4) is rotatably connected to multiple balls (43) through multiple ball grooves, and the balls (43) roll in contact with the outer wall of the oil cylinder (1).

8. The electrically assisted two-stage hydraulic cylinder according to claim 1, characterized in that: The tail end of the second oil cylinder (2) has two baffles (21) fixed symmetrically, and the two baffles (21) are respectively set close to the opposite side walls of the first oil cylinder (1).

9. The electrically assisted two-stage hydraulic cylinder according to claim 1, characterized in that: The oil cylinder 2 (2) is rotatably connected to a stop wheel (22) on the side opposite to the oil cylinder 1 (1).

Images