Wide-angle steering full-hydraulic steering gear

Abstract

The invention relates to a wide-angle steering full-hydraulic steering gear, and belongs to the technical field of steering gears. The problems that when an existing full-hydraulic steering gear adopts a sheet-type elastic piece, the turning angle between a valve element and a valve sleeve is small in the steering process, the flow speed of hydraulic oil is high, vehicle steering is sensitive, and impact vibration of a steering mechanism is likely to be caused are solved. The device comprises a conversion valve and a cycloid motor, wherein the conversion valve and the cycloid motor are connected into a whole through a separation disc; the conversion valve comprises a valve body, a valve element and a valve sleeve. The valve element is rotationally installed on the valve body through a bearing, and the connecting end of the valve element is connected with the steering column. The valve element is rotationally arranged in the valve sleeve in a sleeved mode and connected with a rotor of the cycloid motor through a coupler. A torsion type elastic piece is arranged between the valve element and the valve sleeve so that relative rotation between the valve element and the valve sleeve can be achieved. The rotating angle between the valve element and the valve sleeve is large, so that the flow speed of hydraulic oil is reduced, hydraulic flow impact vibration is small, a steering system buffer valve, a shock absorber and an energy accumulator can be omitted, and cost is saved.

Description

Technical Field

[0001] The present invention relates to a wide-angle steering full hydraulic steering gear, belonging to the technical field of steering gears. Background Art

[0002] A full hydraulic steering gear is a steering device driven by a hydraulic system, which is widely used in scenarios that require efficient control, such as heavy machinery, agricultural machinery, engineering vehicles, and off-road vehicles. Its core feature is that it completely relies on hydraulic energy to transmit power. Through the coordinated work of a hydraulic pump, a hydraulic cylinder, and a control valve, precise and smooth steering operations can be achieved. Compared with traditional mechanical steering systems, full hydraulic steering gears have significant advantages, including light steering operation, fast response speed, strong durability, and the ability to operate stably under high loads and harsh environments. In addition, this system can achieve a flexible design layout, reduce the limitations of mechanical connectors, and provide a larger steering angle and higher control performance for the vehicle. However, due to system complexity and maintenance requirements, full hydraulic steering gears also pose higher requirements for the quality of hydraulic oil and system reliability.

[0003] The existing full hydraulic steering gears have at least the following technical problems: When an articulated vehicle steers, a chip-type elastic member has been used between the spool and the valve sleeve of the full hydraulic steering gear for a long time. According to market data statistics, the proportion of chip-type elastic members reaches 99.9% in the steering gear industry. The chip-type elastic member allows the spool to have a free rotation angle relative to the valve sleeve. However, due to the limitations of its own structure, the free rotation angle is small, resulting in small opening degrees of each link of the spool and the valve sleeve during steering of the steering gear, high flow rate of hydraulic oil, sudden supply of hydraulic oil, sensitive vehicle steering, and easy occurrence of impact vibration of the steering mechanism, making it easy for the driver to get fatigued during operation. Therefore, how to solve the problem that the existing full hydraulic steering gear uses a chip-type elastic member, resulting in a small rotation angle between the spool and the valve sleeve during steering, high flow rate of hydraulic oil, and easy occurrence of impact vibration of the steering mechanism has become a technical problem in the industry. Summary of the Invention

[0004] In view of the problems and deficiencies in the prior art, the present application provides a wide-angle steering full hydraulic steering gear to solve the above technical problems.

[0005] To achieve the above object, the present application provides the following technical solution: A wide-angle steering full hydraulic steering gear includes a steering valve and a cycloid motor. The steering valve and the cycloid motor are connected as a whole through a spacer disk. The steering valve includes a valve body, a spool, and a valve sleeve. The spool is rotatably installed in the valve body through a bearing, and its connecting end is connected to the steering column. The spool is rotatably sleeved in the valve sleeve and is connected to the rotor of the cycloid motor through a coupling. A torsional elastic member is provided between the spool and the valve sleeve to form relative rotation between the spool and the valve sleeve.

[0006] Specifically, the torsional elastic member is a cylindrical helical torsion spring; the cylindrical helical torsion spring is sleeved outside the valve core, and it has two abutting ends, one of which is installed on the valve core and the other is installed on the valve sleeve.

[0007] Specifically, the diameter dimension of the end of the valve core on the side away from the torsional elastic member is smaller than the diameter dimension of the valve core on the side of the torsional elastic member. Such a setting is to reduce the contact area between the valve core and the valve sleeve to ensure the rotational flexibility of the valve core.

[0008] Specifically, an oil distribution channel is axially opened on the valve body towards the cycloid motor; the oil distribution channel includes a main oil channel and two radial oil channels; one end of the main oil channel extends to the cycloid motor, and the other end is respectively connected to the two radial oil channels.

[0009] Specifically, the radial oil channels are six radial holes evenly spaced along the circumferential direction of the valve body, and one end of the radial hole communicates with the main oil channel; the two radial oil channels are parallel to each other.

[0010] Specifically, two rows of oil distribution holes are provided on the valve sleeve, and each row of oil distribution holes corresponds to each radial oil channel one by one; six oil distribution holes are evenly spaced along the circumferential direction of the valve sleeve in each row.

[0011] Specifically, an oil return distribution hole is provided at a position on the valve sleeve corresponding to the main oil channel of the valve body, and the oil return distribution holes are evenly spaced along the circumferential direction of the valve sleeve, and the number of oil return distribution holes is several. Such a setting is to effectively increase the oil return area, reduce the flow rate of the hydraulic oil, and reduce the hydraulic shock vibration.

[0012] Specifically, oil distribution grooves are provided at positions on the valve core corresponding to the two radial oil channels, and the number of oil distribution grooves is three, and the three oil distribution grooves are evenly distributed along the circumferential direction of the valve core. Such a setting is to realize that the valve core adopts a design of three oil distribution grooves to distribute oil to the rotor stator, and the oil distribution is more uniform and stable.

[0013] Specifically, a pressure equalizing groove is provided on the valve sleeve. Such a setting is to open a pressure equalizing groove on the valve sleeve to play a role in pressure equalization and impurity collection, so as to improve the rotational flexibility between the valve core and the valve sleeve.

[0014] Specifically, the oil distribution groove is an arc-shaped structure, and the groove depth dimension of the oil distribution groove is 14 / 75 of the arc diameter dimension, and the length dimension is 3 / 49 of the arc diameter dimension.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: 1. The wide-angle steering full-hydraulic steering gear of the present application includes a steering valve and a cycloidal motor. The steering valve and the cycloidal motor are connected as a whole through a spacer disc. The steering valve includes a valve body, a spool and a valve sleeve. The spool is rotatably installed in the valve body through a bearing, and its connecting end is connected to the steering column. The spool is rotatably sleeved in the valve sleeve and is connected to the rotor of the cycloidal motor through a coupling. A torsional elastic member is provided between the spool and the valve sleeve to form relative rotation between the spool and the valve sleeve. The free rotation angle between the spool and the valve sleeve is increased. The theoretical maximum free rotation angle of the present application can reach 60°. Actually, due to its own structural limitations, the maximum opening degree is 50°, which reduces the flow rate of hydraulic oil and greatly reduces the hydraulic flow impact vibration. By adopting this technology, the buffer valve, shock absorber and accumulator of the steering system can be cancelled, saving costs.

[0016] 2. On the basis described above, the theoretical free rotation angle of the spool and the valve sleeve of the wide-angle steering full-hydraulic steering gear of the present application can reach 60°. The spool is provided with oil distribution grooves for supplying oil to the cycloidal motor, and the number of oil distribution grooves is three, which are evenly distributed along the circumference of the spool. Compared with the traditional full-hydraulic steering gear spool with 6 oil distribution grooves, the spool structure of the present application is simple and the production cost is low. By providing oil distribution holes at corresponding positions of the valve body and the valve sleeve, uniform and stable oil supply to the cycloidal motor is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the wide-angle steering full-hydraulic steering gear of this embodiment; Figure 2 is a schematic structural diagram of the valve body of the wide-angle steering full-hydraulic steering gear of this embodiment; Figure 3 is a schematic structural diagram of the valve sleeve of the wide-angle steering full-hydraulic steering gear of this embodiment; Figure 4 is a schematic structural diagram of the spool of the wide-angle steering full-hydraulic steering gear of this embodiment; Figure 5 is Figure 4 the A-A cross-sectional view in Figure 6 is a schematic structural diagram of the cylindrical helical torsion spring of the wide-angle steering full-hydraulic steering gear of this embodiment; Figure 7 is a side view of the structure of the cylindrical helical torsion spring of the wide-angle steering full-hydraulic steering gear of this embodiment; Figure 8 is a schematic structural diagram of a traditional leaf spring in the prior art; Figure 9 is a combined comparison schematic diagram of the oil distribution grooves of the spool of this embodiment and the traditional right-angle type oil distribution grooves; Figure 10Schematic diagram of the oil passage area of the spool when the relative rotation angle between the spool and the valve sleeve of this embodiment is 15° (both the spool and the valve sleeve are in the unfolded state); Figure 11 Schematic diagram of the oil passage area of the spool when the relative rotation angle between the spool and the valve sleeve of this embodiment is 45° (both the spool and the valve sleeve are in the unfolded state); Figure 12 Hydraulic impact force curve diagram during the steering of the standard steering gear in the comparative example; Figure 13 Hydraulic impact force curve diagram during the steering of the full hydraulic steering gear with wide - angle steering of this embodiment. Specific Embodiments

[0018] In order to make the purpose and advantages of the present invention clearer, the present invention will be specifically described below in conjunction with embodiments. It should be understood that the following text only describes one or several specific implementation manners of the present invention, and does not strictly limit the scope of protection specifically claimed by the present invention.

[0019] Please refer to Figures 1-7 , this embodiment discloses a full hydraulic steering gear with wide - angle steering, which includes a steering valve and a cycloidal motor 5. The steering valve 15 and the cycloidal motor are connected into one body through a spacer 16; the steering valve includes a valve body 1, a spool 3 and a valve sleeve 2; the spool is rotatably installed in the valve body through a bearing, and its connecting end is connected to the steering column; the spool is rotatably sleeved in the valve sleeve and is connected to the rotor of the cycloidal motor through a coupling; a torsional elastic member 4 is provided between the spool and the valve sleeve to constitute the relative rotation between the spool and the valve sleeve. And the torsional elastic member 4 of this embodiment is a cylindrical helical torsion spring. And the diameter dimension of the end of the spool 3 on the side far from the torsional elastic member is smaller than the diameter dimension of the spool on the side of the torsional elastic member. In addition, pressure equalizing grooves 12 are provided on the valve sleeve of this embodiment.

[0020] Further, the cylindrical helical torsion spring of this embodiment is sleeved outside the spool 3 and has two abutting ends, one of which is installed on the spool 3 and the other is installed on the valve sleeve 2.

[0021] An oil distribution passage is axially opened on the valve body 1 of this embodiment towards the cycloidal motor; the oil distribution passage includes a main oil passage 6 and two radial oil passages 7; one end of the main oil passage extends to the cycloidal motor, and the other end is respectively communicated with the two radial oil passages.

[0022] Further, six radial holes 8 are evenly spaced along the circumferential direction of the valve body in the radial oil passage 7 of this embodiment, and one end of the radial hole is communicated with the main oil passage; the two radial oil passages are parallel to each other.

[0023] There are two rows of oil distribution holes 9 provided on the valve sleeve of this embodiment, and each row of oil distribution holes is arranged in one-to-one correspondence with each radial oil passage; six oil distribution holes are evenly spaced along the circumference of the valve sleeve in each row. And at the position corresponding to the main oil passage of the valve body on the valve sleeve of this embodiment, there is an oil return distribution hole 11, and the oil return distribution holes are evenly spaced along the circumferential direction of the valve sleeve, and the number of oil return distribution holes is four.

[0024] In addition, at the positions corresponding to the two radial oil passages on the spool of this embodiment, there are oil distribution grooves 10 provided. The number of oil distribution grooves on the spool is three, and the three oil distribution grooves are evenly distributed along the circumference of the spool. The oil distribution groove of this embodiment is of an arc-shaped structure, which is machined by a grinding wheel with a diameter of 15 mm, its groove depth dimension is 2.8 mm, and its length dimension is 24.5 mm, which can effectively reduce the working noise of the steering gear. As Figure 9 shown, the dotted line in the figure is the right-angle oil distribution groove opened on the existing conventional spool, and the gray area in the figure is the arc-shaped oil distribution groove opened in this embodiment. Such a setting is to achieve that when using the right-angle oil distribution groove, when the hydraulic oil fluid impacts the right-angle edge, it will cause high-frequency vibration of the spool or valve sleeve, such as chatter. When using the arc-shaped oil distribution groove of this embodiment, the radian design can disperse the impact force of the hydraulic oil fluid, reduce local stress concentration, and at the same time improve the dynamic stability of fluid mechanics and reduce the noise of structural vibration transmission.

[0025] Working principle: When the wide-angle steering full-hydraulic steering gear of this embodiment is in use, when the steering column is in the middle position, the spool and the valve sleeve are in the middle position under the action of the cylindrical spiral torsion spring. The oil coming from the oil pump enters the inside of the spool through the oil holes on the end of the valve sleeve and the spool, and then returns to the fuel tank through the oil port. When the steering wheel drives the steering column to turn right (or left), it drives the spool to turn right (or left). Because there is a maximum rotation amount of 50° between the spool and the valve sleeve, the spool will overcome the elastic force of the cylindrical spiral torsion spring between the spool sleeves. Therefore, the spool rotates relative to the valve sleeve. At this time, the oil distribution groove on the spool is connected to the oil inlet passage of the valve sleeve. The oil coming from the pump passes through the valve sleeve and the spool oil groove, and then flows from the valve sleeve to the cycloid motor, pushing the rotor to rotate relative to the stator. At the same time, the oil discharged from the rotor and the stator enters one chamber of the steering cylinder through the oil return distribution hole 11 on the valve sleeve, that is, the oil outlet A (or B) on the steering gear, causing the piston rod of the cylinder to extend (contract), pushing the steering wheel to turn right (or left). The oil in the other chamber of the cylinder enters the valve sleeve from the oil port B (or A), and then returns to the fuel tank through the oil return hole of the spool, thus realizing the steering function.

[0026] When the wide-angle steering full-hydraulic steering gear of this embodiment is steering, compared with the traditional leaf spring, such as Figure 8As shown in the figure, it consists of a straight piece 13 and a bent piece 14. The straight piece limits the torsion range, and the maximum opening degree is 10°. The main reasons are as follows: 1. From a mechanical perspective, the straight piece spring relies on axial compression or bending deformation to provide elastic force, and the rotation of the valve core requires converting this axial force into a rotational torque through a lever arm. When the rotation angle increases, the compression amount required by the spring will increase sharply in a non-linear manner, quickly exceeding the elastic limit of the spring material. For example, existing leaf springs are mostly made of 65Mn steel, and when the rotation angle of 65Mn steel exceeds 10°, the edge stress will exceed 800 Mpa, resulting in permanent deformation or fracture of the spring. 2. From the perspective of space constraints, the installation gap between the valve core and the valve sleeve is usually only 2-3 mm. The straight piece spring must ensure sufficient stiffness, that is, the single-piece thickness ≥ 0.5 mm, and also reserve a deformation space. Through testing, it is known that when the spring rotates at an angle of 10°, at least 1.2 mm of axial space is required. This makes it inevitable that when using a traditional leaf spring and increasing the rotation angle, the spring will inevitably have a space conflict with the valve body. Therefore, the torsion spring itself has a relatively large rotation angle, generally between 180° and 360°. Therefore, using a traditional leaf spring will cause the maximum opening degree of the rotation angle to be 10° due to its own limitations. Using a torsion spring can increase the free rotation angle of the valve core and the valve sleeve. An increase in the free rotation angle between the valve core and the valve sleeve, that is, an increase in the opening degree of the valve core and the valve sleeve, usually means an increase in the oil passage area of the hydraulic system. This will directly affect the flow rate and flow of the hydraulic oil, and further affect the pressure fluctuation and shock vibration of the system.

[0027] According to the relationship between the flow rate and flow of the hydraulic oil and the flow area (i.e., the oil port opening degree between the valve core and the valve sleeve), it is determined by the continuity equation: Q = A·V; Where: Q is the flow rate (m³ / s), A is the flow area (m²), and V is the flow velocity (m / s).

[0028] In this embodiment, through testing, such as Figures 10-11 , when the relative rotation angle of the steering gear increases, the flow area A increases. For example, when the rotation angle of the steering gear increases from 15° to 45°, the oil passage area of its unloading circuit increases from 11.1 mm² to 15.9 mm², the enlarged oil return increases from 2.39 mm² to 6.97 mm², the oil inlet return increases from 1.94 mm² to 29.89 mm², and the oil return increases from 5.5 mm² to 32.34 mm². According to the above formula, it can be concluded that when the flow rate Q remains unchanged, an increase in the flow area A will cause the flow velocity V of the hydraulic oil to decrease.

[0029] A decrease in the flow rate Q means that the volume of hydraulic oil passing through the system per unit time decreases, and the pressure fluctuation amplitude of the system decreases. Pressure fluctuation is one of the main sources of shock vibration. Therefore, a decrease in the flow rate will directly reduce the vibration.

[0030] According to the pressure shock (water hammer effect) in the hydraulic system is proportional to the square of the flow velocity V: ΔP ∝ ρ·v 2 Where: ΔP is the pressure shock, and ρ is the density of the hydraulic oil. When the flow velocity V decreases, the pressure shock ΔP decreases significantly.

[0031] When the relative rotation angle of the steering gear increases, the flow path of the hydraulic oil may become more complex. This will increase the damping effect of the system, further suppressing the sudden changes in flow rate and pressure, thereby reducing shock vibration.

[0032] In order to further test that the wide-angle steering full hydraulic steering gear of this embodiment can effectively reduce shock vibration, through experimental comparison, the comparative example is an existing conventional standard steering gear, which uses a plate-type elastic member, and a right-angled oil distribution groove is opened on the spool. By testing the steering gear under the same test actions and test time, the hydraulic impact force of the steering gear is measured, such as Figures 12-13 , the test condition is to first operate the steering gear to turn clockwise and hold for a period of time, then immediately reverse to turn counterclockwise and hold for a period of time, and record the numerical change curve of the hydraulic impact force of the steering gear. It can be seen from the figure that the impact force of this embodiment is relatively stable. Therefore, increasing the relative rotation angle of the steering gear can effectively reduce the flow velocity and flow shock vibration of the hydraulic oil, thereby improving the stability and reliability of the system and the operation comfort of the driver.

[0033] The above has described the implementation mode of the present application in detail in combination with the embodiments. However, the present application is not limited to the above implementation mode. For those of ordinary skill in the art of this technology, after learning the content recorded in the present application, without departing from the principle of the present application, several equivalent transformations and substitutions can still be made to it, and these equivalent transformations and substitutions should also be regarded as belonging to the protection scope of the present application.

Claims

1. A wide-angle steering fully hydraulic steering gear, comprising a steering valve and a cycloidal motor, characterized in that: The steering valve and the gerotor motor are connected as a whole via a spacer; the steering valve comprises a valve body, a valve core and a valve sleeve; the valve core is rotatably mounted on the valve body via a bearing, and its connecting end is connected to the steering column; the valve core is rotatably sleeved in the valve sleeve, and is connected to the rotor of the gerotor motor via a coupling; a torsional elastic member is provided between the valve core and the valve sleeve to constitute relative rotation between the valve core and the valve sleeve.

2. A wide-angle steering fully hydraulic steering gear according to claim 1, characterized in that: The torsion elastic member is a cylindrical helical torsion spring; the cylindrical helical torsion spring is sleeved on the outside of the valve core and is provided with two stop ends, one of which is installed on the valve core and the other is installed on the valve sleeve.

3. A wide-angle steering fully hydraulic steering gear according to claim 2, characterized in that: The diameter of the valve core end at the side of the valve core away from the torsion elastic member is smaller than the diameter of the valve core at the side of the torsion elastic member.

4. The wide-angle steering fully hydraulic steering gear according to claim 1, characterized in that: An oil distribution channel is opened on the valve body axially toward the cycloidal motor; the oil distribution channel includes a main oil channel and two radial oil channels; one end of the main oil channel extends to the cycloidal motor, and the other end is respectively connected to the two radial oil channels.

5. A wide-angle steering fully hydraulic steering gear according to claim 4, characterized in that: The radial oil passage comprises six radial holes evenly spaced apart in the circumferential direction of the valve body, one end of each radial hole is communicated with the main oil passage; and two radial oil passages are parallel to each other.

6. A wide-angle steering fully hydraulic steering gear according to claim 4, characterized in that: The valve sleeve is provided with two rows of oil distribution holes, and each row of oil distribution holes is arranged in one-to-one correspondence with each radial oil passage; each row of oil distribution holes is provided with six oil distribution holes evenly spaced along the circumference of the valve sleeve.

7. The wide-angle steering fully hydraulic steering gear according to claim 1, characterized in that: An oil return distribution hole is arranged on the valve sleeve at a position corresponding to the main oil passage of the valve body, and the oil return distribution holes are evenly spaced along the circumferential direction of the valve sleeve, and the number of the oil return distribution holes is several.

8. The wide-angle steering fully hydraulic steering gear according to claim 4, characterized in that: The valve core is provided with oil distribution grooves at positions corresponding to the two radial oil passages, and the number of the oil distribution grooves is three, and the three oil distribution grooves are evenly distributed and spaced along the circumferential direction of the valve core.

9. The wide-angle steering fully hydraulic steering gear according to claim 1, characterized in that: The valve sleeve is provided with a pressure equalizing groove.

10. The wide-angle steering fully hydraulic steering gear according to claim 8, characterized in that: The oil distribution groove is an arc-shaped structure, and the groove depth dimension of the oil distribution groove is 14 / 75 of the arc diameter dimension, and the length dimension is 3 / 49 of the arc diameter dimension.

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