A structure for slow switching of oil circuits

Abstract

This invention relates to the field of hydraulic valve technology, specifically a structure for slow-speed switching of oil circuits, including a valve body, valve stem, mounting base, stepper motor, connector, and circuit board. The valve body has an oil inlet, a first oil outlet, and a second oil outlet. The valve stem end is fitted to the connector via a T-connector. The connector is connected to the stepper motor output shaft via a ball screw pair, and a bearing is fitted to reduce motion friction. The circuit board integrates a controller and a Hall sensor, and the connector embeds a magnet. These two components work together to achieve closed-loop position feedback, while simultaneously dividing the 10mm total stroke of the valve stem into 10 precise speed control segments. For demanding scenarios, auxiliary structures such as a buffer chamber, double-layer ring sleeve, and buffer ring can be added to further reduce oil shock. This structure, through the synergistic effect of active speed control and passive buffering, solves the problems of large oil shock and vehicle vibration in traditional valve groups, ensuring reliable operation and suitability for various crane boom switching scenarios.

Description

Technical Field

[0001] This invention relates to the field of hydraulic valve technology, specifically a structure for slowly switching oil circuits. Background Technology

[0002] In crane operations, more and more scenarios require the independent control of boom section 1 from boom sections 2, 3, and 4, which places higher demands on the stability of the hydraulic switching valve group.

[0003] When switching booms, the hydraulic pressure changes abruptly, and the rapid movement of the valve stem causes a sharp change in the flow of the oil, resulting in a momentary high-pressure shock. This shock is directly transmitted to the entire vehicle, causing the vehicle to vibrate. This not only affects the accuracy and safety of operation, but also accelerates the wear of components and shortens the service life of the equipment. Traditional valve groups lack effective speed control and buffering mechanisms, and cannot alleviate this problem.

[0004] In addition, the connection between the valve stem and the drive motor must ensure transmission accuracy while reducing the difficulty of processing. Traditional connection methods have extremely high requirements for coaxiality, high processing costs, and large motion friction, which can easily lead to jamming. These problems restrict the performance and reliability of the switching valve group.

[0005] In view of this, the present invention proposes a structure for slow switching of oil circuits, which solves the above-mentioned technical problems. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention discloses a slow-speed switching oil circuit structure, which aims to solve the technical problems of large oil shock and vehicle vibration in traditional valve groups when switching between the first boom and the second, third and fourth boom of a crane.

[0007] The technical solution adopted by the present invention to solve its technical problem is a slow-speed switching oil circuit structure, including a valve body and a valve stem, wherein a stepper motor is fixed to the valve body by a mounting base; The stepper motor and the valve stem are connected by a connecting piece, and the connecting piece and the valve stem are connected by a T-type connection. The mounting base is equipped with a circuit board, the circuit board is configured with a sensor, the connector is equipped with a magnet that cooperates with the sensor, and the circuit board is used to control the rotation speed of the stepper motor to adjust the commutation speed of the valve stem.

[0008] Preferably, the connector is fitted with a bearing, which is used to convert the rotational motion of the stepper motor into linear motion between the connector and the valve stem, and to reduce motion friction.

[0009] Preferably, the total stroke of the valve stem is 10mm, and the circuit board divides the total stroke into 10 segments, each 1mm, through a program to precisely control the speed of the stepper motor in each segment.

[0010] Preferably, the output shaft of the stepper motor and the connecting component are connected by a ball screw pair.

[0011] Preferably, the connection between the valve body and the mounting base is provided with a waterproof sealing structure.

[0012] Preferably, the valve body is provided with an oil inlet, a first oil outlet, and a second oil outlet, and the valve stem controls the oil inlet to selectively connect to the first oil outlet or the second oil outlet when the valve is reversed.

[0013] The beneficial effects of this invention are: This structure, through the cooperation of a stepper motor and circuit board, achieves segmented and precise speed control of the valve stem, reducing oil shock at the source and effectively solving the problem of overall vehicle vibration during boom switching. The T-type connection relaxes the coaxiality requirements, reduces processing costs, and, in conjunction with bearings, reduces motion friction, ensuring smooth reversing. A combination of magnets and Hall sensors achieves closed-loop position feedback, improving positioning accuracy. An optional buffer structure further enhances stability, adapting to the high-demand scenarios of heavy-duty cranes. The overall structure balances low power consumption, high efficiency, and high reliability, significantly improving the performance and service life of the valve assembly. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 This is a schematic diagram of the overall connection structure of the present invention; Figure 2 This is a front view schematic diagram of the present invention; Figure 3 for Figure 2 A schematic cross-sectional view along the AA direction in Embodiment 1 of the present invention; Figure 4 for Figure 2 A cross-sectional view along the AA direction in Embodiment 2 of the present invention; Figure 5 for Figure 4 Enlarged diagram of point B in the image; Figure 6 This is a partial cross-sectional view of the valve body of the present invention in Embodiment 2; Figure 7 for Figure 6 Enlarged view of point C in the middle; Figure 8 for Figure 6 Enlarged diagram of point D in the diagram; In the picture: 1. Valve body; 2. Valve stem; 3. Mounting base; 4. Stepper motor; 5. Connector; 6. Circuit board; 11. Oil inlet; 12. First oil outlet; 13. Second oil outlet; 51. Magnet; 52. Bearing; 7. Buffer chamber; 71. Ring sleeve; 72. Compression spring; 73. Threaded sleeve; 111. Adjusting bolt; 112. Sealing ring; 113. Buffer ring; 131. Oil hole; 14. Transition chamber; 15. Through hole; 16. Sealing strip; 161. Stop hole; 162. Plug; 163. Transition spring; 91. Wall hole. Detailed Implementation

[0016] To make the technical means, creative features, objectives, and effects of this invention easier to understand, the following is a summary. The present invention will be further described in conjunction with specific embodiments.

[0017] The slow-speed switching hydraulic circuit structure disclosed in this invention aims to solve the technical problems of large hydraulic shock and vehicle vibration caused by traditional valve groups when switching between boom sections 1 and 2, 3, and 4 of a crane. It is suitable for conventional and heavy-duty crane scenarios with stringent stability requirements. Its overall structure, working principle, and technical effects are as follows:

[0018] Example 1:

[0019] like Figures 1 to 3 As shown, the present invention provides a structure for slowly switching oil circuits, which mainly includes a valve body 1, a valve stem 2, a mounting base 3, a stepper motor 4, a connector 5, and a circuit board 6.

[0020] like Figures 1 to 3 As shown, the valve body 1 is integrally die-cast from high-strength aluminum alloy. The inner cavity is a multi-level smooth cylindrical stepped channel. An oil inlet 11 is opened on one side, and a first oil outlet 12 and a second oil outlet 13 are opened at intervals along the axial direction on the other side. The oil outlets are connected to the inner cavity of the valve body 1 through stepped holes to ensure sealing. like Figures 1 to 3 As shown, the valve stem 2 is precision machined from 45# steel with a chrome-plated surface. Its diameter is fitted with the stepped surface of the valve body 1 (gap ≤ 0.02mm), and the total stroke is designed to be 10mm. A T-shaped groove is machined at the end for mating with the connector 5. The mounting base 3 is a frame structure, fixed to the end flange of the valve body 1 by four sets of internal hexagonal bolts. The inner side has a reserved moving cavity for the connector 5, and the outer side has a motor mounting shoulder to ensure the coaxiality of the stepper motor 4. At the same time, a fluororubber O-ring is fitted into the sealing groove of the end flange of the valve body 1 to form a waterproof sealing structure. The mounting area of ​​the circuit board 6 is supplemented with waterproof sealant, so that the overall protection level reaches IP65, which meets the waterproof requirements of crane outdoor operation.

[0021] like Figures 1 to 3As shown, the stepper motor 4 is fixed to the shoulder of the mounting base 3 via a motor flange. The output shaft passes through the center hole of the mounting base 3 and is connected to the connector 5 via a ball screw pair, realizing a backlash-free conversion from rotary motion to linear motion. One end of the connector 5 has an internal threaded hole adapted to the ball screw, and the other end has an integrally formed T-shaped protrusion. The T-shaped protrusion is embedded into the T-shaped groove of the valve stem 2 and fixed by a transverse pin, forming a detachable T-shaped connection structure. This reduces the coaxiality requirement between the stepper motor 4 and the valve stem 2 (the coaxiality tolerance can be relaxed to 0.1mm), reducing processing costs.

[0022] like Figures 1 to 3 As shown, a deep groove ball bearing 52 is installed in the middle of the connecting piece 5. The outer ring of the bearing 52 slides with the inner cavity of the mounting seat 3, which converts linear motion friction into rolling friction and reduces the friction coefficient to below 0.01 to ensure smooth motion. Neodymium iron boron permanent magnets 51 are also embedded in its side wall, with the magnetic poles arranged along the direction of motion.

[0023] like Figures 1 to 3 As shown, the circuit board 6 integrates an STM32F103 microcontroller, a Hall sensor (model A3144), and a power module. It is fixed to the inner wall of the mounting base 3 with screws. The distance between the detection surface of the Hall sensor and the magnet 51 is controlled at 2-3mm to realize the real-time detection of the position of the valve stem 2 with a detection accuracy of ≤0.1mm. It also has a pre-stored segmented control program that divides the total stroke of the valve stem 2 (10mm) into 10 segments (1mm each). The microcontroller outputs pulse signals to control the rotation speed of the stepper motor 4.

[0024] Working principle and control logic: Segmented speed control: Circuit board 6 pre-stores a segmented control program, dividing the total 210mm stroke of the valve stem into 10 equal segments (1mm each). The microcontroller outputs pulse signals to control the rotation speed of stepper motor 4. For example, during boom switching, the program is set as follows: the speed of segments 1-2 (starting segment) is 100r / min (corresponding to a valve stem movement speed of 1mm / s); the speed of segments 3-6 (effective stroke segment) decreases to 20r / min (corresponding to a valve stem movement speed of 0.2mm / s); and the speed of segments 7-10 (ending segment) increases back to 100r / min. This "slow-slower-slower" speed curve reduces the impact during oil switching. See the table below.

[0025] Position closed-loop feedback: When the stepper motor 4 drives the valve stem 2 to move, the magnet 51 moves synchronously with the connecting part 5. The Hall sensor detects the position signal of the magnet 51 in real time and feeds it back to the microcontroller. The microcontroller compares the preset stroke with the actual stroke, dynamically adjusts the output pulse frequency, corrects the speed of the stepper motor 4, avoids overtravel or positioning deviation of the valve stem 2, and ensures that the reversing position accuracy is ≤0.2mm.

[0026] Oil circuit switching process: In the initial state, valve stem 2 blocks the second oil outlet 13, and oil inlet 11 is connected to the first oil outlet 12, with crane boom section 1 operating. When switching to boom sections 2, 3, or 4 is required, the controller sends a switching signal, and circuit board 6 starts stepper motor 4 to rotate forward. Through the ball screw pair, it drives connecting piece 5 and valve stem 2 to move axially, gradually blocking the first oil outlet 12 and opening the second oil outlet 13. After the switching is completed, stepper motor 4 self-locks, valve stem 2 remains positioned, and oil inlet 11 stably supplies oil to the second oil outlet 13. The entire switching process is time-efficient, the oil impact pressure is lower than that of traditional valve groups, and the overall vehicle vibration amplitude is small, meeting usage requirements.

[0027] Example 2:

[0028] The difference between this embodiment and Embodiment 1 is that, based on Embodiment 1, this embodiment adds an active + passive coordinated buffer structure to further improve the smoothness of oil circuit switching. It is suitable for heavy-duty crane scenarios with higher requirements for oil shock control. The specific structure and working principle are as follows: like Figures 4 to 8 As shown, it includes an annular groove-shaped buffer cavity 7 surrounding the oil inlet 11 and opened on the inner wall of the valve body 1. The buffer cavity 7 is connected to the oil inlet 11 through two radially distributed wall holes 91 with a diameter of 2 mm to realize oil diversion buffering.

[0029] like Figure 5 , Figure 6 and Figure 8 As shown, a double-layer coaxial wear-resistant nylon ring 71 is slidably assembled inside the buffer chamber 7. The side wall of the upper ring 71 is sealed to the inner wall of the buffer chamber 7 by an O-ring. Four sets of evenly distributed compression springs 72 with an elastic coefficient of 5 N / mm are connected between the top of the lower ring 71 and the bottom of the upper ring 71. When the oil enters the buffer chamber 7 through the wall hole 91, it can push the upper ring 71 down and absorb the impact energy of the oil through spring compression. A threaded sleeve 73 is integrally formed at the bottom of the lower ring 71. A through hole is opened at the corresponding position on the side wall of the valve body 1. The adjusting bolt 111 passes through the through hole and is engaged with the threaded sleeve 73 through the thread. A slot is provided at the outer end to facilitate tool turning. A fluororubber sealing ring 112 is fitted on the mating surface of the valve body 1 and the adjusting bolt 111 to prevent oil leakage. The initial gap of the double-layer ring 71 can be adjusted by turning the adjusting bolt 111 (adjustment range 1-6 mm), thereby controlling the effective oil inlet capacity of the buffer chamber 7.

[0030] like Figure 7 As shown, a buffer ring 113 made of elastic rubber is fixedly installed at the step surface where the valve stem 2 is located. The side of the buffer ring 113 facing the valve stem 2 is an inclined surface with an inclination angle of 30°. An oil hole 131 with a diameter of 2mm is opened at the center of the inclined surface. The top of the inclined surface slides in contact with the outer wall of the valve stem 2 to form a secondary buffer surface. like Figures 5 to 8 As shown, a transverse transition cavity 14 is also provided inside the valve body 1. A set of through holes 15 are provided on the upper and lower sides of the transition cavity 14, respectively connecting the buffer cavity 7 and the inner cavity of the buffer ring 113. The sealing strip 16 with an "F" structure is slidably assembled in the transition cavity 14. A stop hole 161 adapted to the wall hole 91 is provided at its lower end. A plug 162 for sealing the through hole 15 is fixedly installed in the middle. A transition spring 163 is connected between the middle of the sealing strip 16 and the inner wall of the transition cavity 14. The top extends to the stepped surface and slides in contact with the outer wall of the valve stem 2.

[0031] Working principle and control logic: When the valve stem 2 is not moved, it is stationary at the stepped surface position. There is no oil flow in either of the two oil outlets. At this time, the valve stem 2 is in contact with the top of the sealing strip 16 and keeps it pressed down. The transition spring 163 is in the maximum compression state. The stop hole 161 and the wall hole 91 are completely overlapped. The plug 162 blocks the through hole 15 of the transition cavity 14. The oil enters the buffer cavity 7 from the oil inlet 11 through the wall hole 91 and the stop hole 161, pushing the upper ring 71 down to compress the spring 72 and initially absorbing the oil pressure fluctuation. Upon receiving the switching signal, the stepper motor 4 starts according to the segmented speed control program of the first embodiment. When the valve stem 2 moves, the valve stem 2 gradually moves away from the oil port position where oil needs to be discharged. At this time, the sealing strip 16 on the same side as the oil outlet gradually disengages from the valve stem 2 and is reset and moved upward under the elastic action of the transition spring 163 (at this time, the sealing strip 16 on the other side is still in the downward sealing state). As the sealing strip moves upward in the transition cavity 14, the stop hole 161 and the wall hole 91 partially overlap until they are completely misaligned (the oil flow rate is gradually adjusted). At the same time, the plug 162 moves upward to open the through hole 15. At this time, under the combined action of the compression spring 72 and the oil pressure, the oil in the buffer chamber 7 enters the inner cavity of the buffer ring 113 through the transition chamber 14 and the through hole 15, and is sprayed out at an angle through the inclined oil hole 131 of the buffer ring 113, forming a 30° angle with the main oil flow direction when the valve stem 2 reverses, further slowing down the main oil flow rate. If the buffer strength needs to be adjusted, the initial gap of the double-layer ring 71 can be changed by turning the adjusting bolt 111, and the oil capacity of the buffer chamber 7 can be adjusted to adapt to the impact control requirements under different working conditions.

[0032] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A structure for slowly switching oil circuits, comprising a valve body (1) and a valve stem (2), characterized in that: The valve body (1) is fixed with a stepper motor (4) via a mounting base (3); The stepper motor (4) and the valve stem (2) are connected by a connector (5), and the connector (5) and the valve stem (2) are connected by a T-type connection. The mounting base (3) is provided with a circuit board (6), the circuit board (6) is equipped with a sensor (61), the connector (5) is provided with a magnet (51) that cooperates with the sensor (61), and the circuit board (6) is used to control the rotation speed of the stepper motor (4) to adjust the commutation speed of the valve stem (2).

2. The structure for slowly switching oil circuits according to claim 1, characterized in that: The connector (5) is fitted with a bearing (52), which is used to convert the rotational motion of the stepper motor (4) into the linear motion of the connector (5) and the valve stem (2) and reduce motion friction.

3. The structure for slowly switching oil circuits according to claim 1, characterized in that: The total stroke of the valve stem (2) is 10mm. The circuit board (6) divides the total stroke into 10 segments (1mm each) through a program to precisely control the speed of the stepper motor (4) in each segment.

4. The structure for slowly switching oil circuits according to claim 1, characterized in that: The output shaft of the stepper motor (4) and the connector (5) are connected by a ball screw pair.

5. The structure for slowly switching oil circuits according to claim 1, characterized in that: The connection between the valve body (1) and the mounting base (3) is provided with a waterproof sealing structure.

6. The structure for slowly switching oil circuits according to claim 1, characterized in that: The valve body (1) is provided with an oil inlet (11), a first oil outlet (12) and a second oil outlet (13). When the valve stem (2) reverses, it controls the oil inlet (11) to selectively connect to the first oil outlet (12) or the second oil outlet (13).

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