Hydraulic control system for suspension front axle

Abstract

The utility model provides a suspension front axle hydraulic control system which comprises a front axle oil cylinder, a first energy accumulator, a second energy accumulator, a first proportional valve, a second proportional valve and an oil supplementing unit, the first energy accumulator is connected with the first proportional valve, and the first proportional valve is connected with the piston rod side of the front axle oil cylinder; the second energy accumulator is connected with a second proportional valve; the second proportional valve is connected with the cylinder body side of the front axle oil cylinder; one end of the oil supplementing unit is connected with the piston rod side of the front axle oil cylinder, and the other end of the oil supplementing unit is connected with the cylinder body side of the front axle oil cylinder. According to the utility model, kinetic energy is absorbed through the first energy accumulator, the second energy accumulator and the front axle oil cylinder, so that bumping and vibration of the front axle are relieved; the oil pressure exchange resistance of the front axle oil cylinder is adjusted through the first proportional valve and the second proportional valve, so that the vibration frequency and amplitude of the front axle are adjusted, it is guaranteed that the front axle is suspended within the proper frequency and amplitude, and the comfort level of a driver and passengers is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of tractor suspended front axles, in particular to a suspended front axle hydraulic control system. Background Art

[0002] Tractors have complex operating conditions, with various implements often attached to the front and rear, and work on uneven terrain. Traditional rigid front axle suspension systems cannot effectively reduce the bumps and vibrations at the front of the vehicle, causing discomfort and increased fatigue for drivers and passengers.

[0003] In the existing front axle suspension system, one end of the oil cylinder is connected to the bracket of the vehicle body, and the other end of the oil cylinder is connected to the rocker arm. The front axle is set on the rocker arm, and the oil cylinder is controlled to be in the middle position (i.e., the extension is about 50%) to absorb vibration, thereby reducing the bumps and vibrations of the front of the vehicle. However, due to the complex working terrain of the tractor, when the terrain changes, the vibration frequency and amplitude of the front axle change accordingly, and the resistance of the hydraulic cylinder cannot be adaptively adjusted according to the vibration amplitude of the front axle, making the vibration frequency and amplitude of the front axle changeable, and cannot effectively improve the comfort of the driver and passengers. Utility Model Content

[0004] The technical problem to be solved by the utility model is: how to adjust the vibration frequency and amplitude of the front axle of a tractor.

[0005] The technical solution of the utility model to solve the above technical problems is as follows:

[0006] The utility model provides a suspended front axle hydraulic control system, comprising a front axle oil cylinder, a first accumulator, a second accumulator, a first proportional valve, a second proportional valve, and an oil replenishing unit, wherein the first accumulator is connected to the first proportional valve, and the first proportional valve is connected to the piston rod side of the front axle oil cylinder; the second accumulator is connected to the second proportional valve, and the second proportional valve is connected to the cylinder body side of the front axle oil cylinder; one end of the oil replenishing unit is connected to the piston rod side of the front axle oil cylinder, and the other end of the oil replenishing unit is connected to the cylinder body side of the front axle oil cylinder.

[0007] The beneficial effects of the utility model are:

[0008] With the utility model, the first accumulator and the second accumulator exchange oil with the cylinder body side and the piston rod side of the front axle oil cylinder respectively to absorb kinetic energy, thereby alleviating the bumps and vibrations of the front of the vehicle; the first proportional valve and the second proportional valve adjust the oil pressure exchange resistance of the front axle oil cylinder, so that when the change amplitude of the front axle has an upward or downward trend, the resistance of the front axle oil cylinder can be adjusted in time, thereby adjusting the vibration frequency and amplitude of the front axle, ensuring that the front axle is suspended within a suitable frequency and amplitude, and improving the comfort of the driver and passengers. In addition, the oil replenishment unit facilitates the charging or depressurization of the front axle oil cylinder, thereby preventing the vibration amplitude of the front axle from exceeding the permitted range.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, the oil replenishing unit includes a first control valve, a second control valve and a third control valve, one end of the third control valve is provided with a pressure oil port, and the other end of the third control valve is connected to the first control valve and the second control valve through branches respectively; the first control valve is connected to the piston rod side of the front axle cylinder, and the second control valve is connected to the cylinder body side of the front axle cylinder.

[0011] The pressure oil port of the third control valve can be used to connect a hydraulic oil source such as a hydraulic pump. When the third control valve is opened, it can provide pressure oil to the first control valve and the second control valve. At this time, opening the first control valve can pressurize the piston rod side of the front axle cylinder, and opening the second control valve can pressurize the cylinder body side of the front axle cylinder. At the same time, the control valve can adopt an electromagnetic reversing valve. When the third control valve does not provide pressure oil, it is convenient to relieve pressure on the piston rod side or cylinder body side of the front axle cylinder. It is easy to operate.

[0012] Furthermore, the third control valve is an electromagnetic reversing valve, and an oil return port is provided on the third control valve; the first control valve and the second control valve are both electromagnetic switch valves.

[0013] When the third control valve is closed, it is in the oil return state. At this time, opening the first control valve can relieve pressure on the piston rod side of the front axle cylinder, and opening the second control valve can relieve pressure on the cylinder body side of the front axle cylinder. It is convenient to control the charging and depressurization process of the front axle cylinder and is easy to operate.

[0014] Furthermore, a first throttle port is provided on the oil circuit from the first control valve to the front axle oil cylinder.

[0015] It is convenient to reduce the pressure relief speed on the piston rod side of the front axle oil cylinder, to adjust the oil pressure and to reduce pressure fluctuations.

[0016] Furthermore, the first throttle port is also connected in parallel with a first one-way valve, and the first one-way valve can allow the hydraulic oil to flow from the first control valve to the piston rod side of the front axle cylinder in one direction.

[0017] It is convenient to quickly replenish oil to the piston rod side of the front axle cylinder. At the same time, the pressure relief on the piston rod side is not affected by the first one-way valve, so fast filling and slow discharge are achieved, which is convenient for adjusting the oil pressure and reducing pressure fluctuations.

[0018] Furthermore, a first pressure gauge is provided on the oil circuit from the first throttle port to the front axle oil cylinder.

[0019] It is convenient to measure the oil pressure on the piston rod side of the front axle oil cylinder, so as to control the pressure charging or pressure relief on the piston rod side of the front axle oil cylinder to avoid excessively high or low pressure, and has good reliability.

[0020] Furthermore, a second throttle port is provided on the oil path from the second control valve to the front axle oil cylinder.

[0021] It is convenient to reduce the pressure relief speed on the cylinder body side of the front axle oil cylinder, adjust the oil pressure and reduce pressure fluctuations.

[0022] Furthermore, the second throttle port is also connected in parallel with a second one-way valve, and the second one-way valve can allow the hydraulic oil to flow from the second control valve to the cylinder body side of the front axle cylinder in one direction.

[0023] It is convenient to quickly replenish oil to the cylinder body side of the front axle cylinder. At the same time, the pressure relief on the cylinder body side is not affected by the second one-way valve, so fast filling and slow discharge are achieved, which is convenient for adjusting the oil pressure and reducing pressure fluctuations.

[0024] Furthermore, a second pressure gauge is provided on the oil circuit from the second throttle port to the front axle oil cylinder.

[0025] It is convenient to measure the oil pressure on the cylinder body side of the front axle oil cylinder, so as to control the pressure charging or pressure relief on the cylinder body side of the front axle oil cylinder to avoid excessively high or low pressure, and the reliability is good.

[0026] Furthermore, a pressure relief branch is provided on the oil circuit from the second throttle port to the front axle oil cylinder, the pressure relief branch is connected to the oil return port, and a pressure relief valve is provided on the pressure relief branch.

[0027] When the load on the front axle cylinder is too large, the overpressure on the cylinder side of the front axle cylinder is relieved through the pressure relief valve, avoiding damage to the front axle cylinder due to excessive bumps and increasing the service life of the entire vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the utility model.

[0029] In the accompanying drawings, the technical features represented by the reference numerals are as follows:

[0030] 1-front axle oil cylinder; 2-first accumulator; 3-second accumulator; 4-first proportional valve; 5-second proportional valve; 6-first control valve; 7-second control valve; 8-third control valve; 9-pressure relief valve; 10-first throttle; 11-first check valve; 12-second throttle; 13-second check valve; 14-first pressure gauge; 15-second pressure gauge;

[0031] P-pressure oil port; T-return oil port. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] This utility model refers to Figure 1 .

[0034] The utility model provides a suspended front axle hydraulic control system, comprising a front axle oil cylinder 1, a first accumulator 2, a second accumulator 3, a first proportional valve 4, a second proportional valve 5, and an oil replenishing unit, wherein the first accumulator 2 is connected to the first proportional valve 4, and the first proportional valve 4 is connected to the piston rod side of the front axle oil cylinder 1; the second accumulator 3 is connected to the second proportional valve 5, and the second proportional valve 5 is connected to the cylinder body side of the front axle oil cylinder 1; one end of the oil replenishing unit is connected to the piston rod side of the front axle oil cylinder 1, and the other end of the oil replenishing unit is connected to the cylinder body side of the front axle oil cylinder 1.

[0035] principle:

[0036] The front axle oil cylinder 1 is a bidirectional oil cylinder, having two interfaces on the cylinder body side and the piston rod side; the interface on the cylinder body side is used to control the extension of the oil cylinder, and the interface on the piston rod side is used to control the shortening of the oil cylinder, which belongs to the prior art. Connect the piston rod side of the front axle oil cylinder 1, that is, connect the first proportional valve 4 to the oil circuit on the piston rod side of the front axle oil cylinder 1; connect the cylinder body side of the front axle oil cylinder 1, that is, connect the second proportional valve 5 to the oil circuit on the cylinder body side of the front axle oil cylinder 1. During installation, the cylinder body of the front axle oil cylinder 1 is connected to the bracket of the vehicle body, the piston rod of the front axle oil cylinder 1 is connected to the rocker arm, the front axle is set on the rocker arm, and the control cylinder is in the middle position (that is, the extension is about 50%).

[0037] When the front axle is subjected to load, the pressure is transmitted to the front axle cylinder 1, increasing the pressure on the cylinder body side or the piston rod side; at the same time, the first accumulator 2 and the second accumulator 3 exchange oil with the cylinder body side and the piston rod side of the front axle cylinder 1 respectively to absorb the load energy, so that the front axle cylinder 1 returns to the middle position, that is, the front axle returns to its original position, thereby alleviating the bumps and vibrations of the front of the vehicle.

[0038] The first proportional valve 4 and the second proportional valve 5 can adjust the opening, and the opening is negatively correlated with the resistance, so as to adjust the oil pressure exchange resistance between the accumulator and the front axle cylinder 1. Initially, the first proportional valve 4 and the second proportional valve 5 are both at the maximum opening. When the front axle change amplitude has an upward trend (that is, the elongation of the front axle cylinder 1 has an increasing trend, or always fluctuates in the direction of elongation), the opening of the second proportional valve 5 is reduced, and the oil pressure exchange resistance on the cylinder body side of the front axle cylinder 1 is increased, thereby reducing the fluctuation amplitude in the elongation direction of the front axle cylinder 1 and increasing the fluctuation frequency in the elongation direction of the front axle cylinder 1. When the front axle change amplitude has a downward trend (that is, the elongation of the front axle cylinder 1 has a decreasing trend, or always fluctuates in the direction of shortening), the opening of the first proportional valve 4 is reduced, and the oil pressure exchange resistance on the piston rod side of the front axle cylinder 1 is increased, thereby reducing the fluctuation amplitude in the shortening direction of the front axle cylinder 1 and increasing the fluctuation frequency in the shortening direction of the front axle cylinder 1.

[0039] The elongation of the front axle cylinder 1 needs to fluctuate within the permitted range (generally within the range of 50% ± 5%). When used for a long time, the oil pressure of the front axle cylinder 1 and the accumulator will inevitably decrease, which will increase the fluctuation range and require the replenishment unit to replenish oil. When the fluctuation amplitude of the front axle cylinder 1 exceeds +5% (+ indicates the extension direction), the replenishment unit will release pressure on the cylinder body side of the front axle cylinder 1 or charge pressure on the piston rod side; when the fluctuation amplitude of the front axle cylinder 1 exceeds -5% (- indicates the shortening direction), the replenishment unit will release pressure on the piston rod side of the front axle cylinder 1 or charge pressure on the cylinder body side; thereby returning the elongation of the front axle cylinder 1 to the preset range.

[0040] In summary, the utility model uses the first accumulator 2 and the second accumulator 3 to exchange oil with the cylinder body side and the piston rod side of the front axle oil cylinder 1 respectively to absorb kinetic energy and alleviate the bumps and vibrations of the front of the vehicle; the first proportional valve 4 and the second proportional valve 5 adjust the oil pressure exchange resistance of the front axle oil cylinder 1, so that when the change amplitude of the front axle has an upward or downward trend, the resistance of the front axle oil cylinder 1 can be adjusted in time, thereby adjusting the vibration frequency and amplitude of the front axle, ensuring that the front axle is suspended within a suitable frequency and amplitude, and improving the comfort of the driver and passengers. In addition, the oil replenishment unit facilitates the charging or depressurization of the front axle oil cylinder 1, avoiding the vibration amplitude of the front axle from exceeding the permitted range.

[0041] Furthermore, the oil replenishing unit includes a first control valve 6, a second control valve 7 and a third control valve 8, one end of the third control valve 8 is provided with a pressure oil port P, and the other end of the third control valve 8 is connected to the first control valve 6 and the second control valve 7 through branches respectively; the first control valve 6 is connected to the piston rod side of the front axle cylinder 1, and the second control valve 7 is connected to the cylinder body side of the front axle cylinder 1.

[0042] The pressure oil port P of the third control valve 8 can be used to connect a hydraulic oil source such as a hydraulic pump. When the third control valve 8 is opened, it can provide pressure oil to the first control valve 6 and the second control valve 7. At this time, opening the first control valve 6 can pressurize the piston rod side of the front axle cylinder 1, and opening the second control valve 7 can pressurize the cylinder body side of the front axle cylinder 1. At the same time, the control valve can adopt an electromagnetic reversing valve. When the third control valve 8 does not provide pressure oil, it is convenient to relieve pressure on the piston rod side or cylinder body side of the front axle cylinder 1. The operation is convenient.

[0043] Furthermore, the third control valve 8 is an electromagnetic reversing valve, and an oil return port T is provided on the third control valve 8; the first control valve 6 and the second control valve 7 are both electromagnetic switch valves.

[0044] An example of operation method: when the fluctuation amplitude of the front axle cylinder 1 exceeds +5%, only the second control valve 7 is opened, and the cylinder side of the front axle cylinder 1 enters the return oil port T of the third control valve 8 through the second control valve 7 to relieve pressure, until the fluctuation amplitude of the front axle cylinder 1 returns to within +5%; when the fluctuation amplitude of the front axle cylinder 1 exceeds -5%, the second control valve 7 and the third control valve 8 are opened, and the hydraulic oil enters the third control valve 8 from the pressure oil port P, and the cylinder side of the front axle cylinder 1 is pressurized through the second control valve 7, until the fluctuation amplitude of the front axle cylinder 1 returns to within -5%.

[0045] When the third control valve 8 is closed, it is in the oil return state. At this time, opening the first control valve 6 can relieve pressure on the piston rod side of the front axle cylinder 1, and opening the second control valve 7 can relieve pressure on the cylinder body side of the front axle cylinder 1. This is convenient for controlling the charging and depressurization process of the front axle cylinder 1 and is easy to operate.

[0046] Furthermore, a first throttle port 10 is provided on the oil path from the first control valve 6 to the front axle oil cylinder 1 .

[0047] It is convenient to reduce the pressure relief speed on the piston rod side of the front axle oil cylinder 1, to adjust the oil pressure and to reduce pressure fluctuations.

[0048] Furthermore, the first throttle port 10 is also connected in parallel with a first one-way valve 11 , and the first one-way valve 11 can allow the hydraulic oil to flow from the first control valve 6 to the piston rod side of the front axle cylinder 1 in one direction.

[0049] It is convenient to quickly replenish oil to the piston rod side of the front axle oil cylinder 1. At the same time, the pressure relief on the piston rod side is not affected by the first one-way valve 11, so that fast filling and slow discharge are achieved, which is convenient for adjusting the oil pressure and reducing pressure fluctuations.

[0050] Furthermore, a first pressure gauge 14 is provided on the oil circuit from the first throttle port 10 to the front axle oil cylinder 1 .

[0051] It is convenient to measure the oil pressure on the piston rod side of the front axle oil cylinder 1, so as to control the pressure charging or pressure relief on the piston rod side of the front axle oil cylinder 1, avoid excessively high or low pressure, and have good reliability.

[0052] Furthermore, a second throttle port 12 is provided on the oil path from the second control valve 7 to the front axle oil cylinder 1 .

[0053] It is convenient to reduce the pressure relief speed on the cylinder body side of the front axle oil cylinder 1, to adjust the oil pressure and to reduce pressure fluctuations.

[0054] Furthermore, the second throttle port 12 is also connected in parallel with a second one-way valve 13 , and the second one-way valve 13 can allow the hydraulic oil to flow from the second control valve 7 to the cylinder body side of the front axle cylinder 1 in one direction.

[0055] It is convenient to quickly replenish oil to the cylinder body side of the front axle oil cylinder 1. At the same time, the pressure relief on the cylinder body side is not affected by the second one-way valve 13, so fast filling and slow discharge are achieved, which is convenient for adjusting the oil pressure and reducing pressure fluctuations.

[0056] Furthermore, a second pressure gauge 15 is provided on the oil circuit from the second throttle port 12 to the front axle oil cylinder 1 .

[0057] It is convenient to measure the oil pressure on the cylinder body side of the front axle oil cylinder 1, so as to control the pressure charging or pressure relief on the cylinder body side of the front axle oil cylinder 1, avoid excessively high or low pressure, and have good reliability.

[0058] Furthermore, a pressure relief branch is provided on the oil circuit from the second throttle port 12 to the front axle oil cylinder 1 , the pressure relief branch is connected to the oil return port T, and a pressure relief valve 9 is provided on the pressure relief branch.

[0059] When the load on the front axle cylinder 1 is too large, the overpressure on the cylinder body side of the front axle cylinder 1 is relieved through the pressure relief valve 9, thereby avoiding damage to the front axle cylinder 1 due to excessive bumps and increasing the service life of the entire vehicle.

[0060] In the description of the present invention, it should be understood that if there are descriptive terms indicating orientation, direction or positional relationship, such as: "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated in this specification is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of understanding the present invention and simplifying the description, and does not indicate or imply that the referred part, element or whole must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0061] In addition, if there are order description terms, such as "first", "second", etc., their purpose in this specification is to facilitate understanding or simplify description. For example, in order to distinguish multiple technical features of the same type or function, but they have to be mentioned separately, this specification may use prefix or suffix order description terms to distinguish them. Therefore, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0062] In the present utility model, if the terms describing the relative functional relationship of the structures are used, such as "install", "connect", "connect", "fix", etc., they should be understood in a broad sense unless otherwise clearly specified and limited. For example, "install", "connect", "connect", etc. can be a fixed connection, a detachable connection, or an integrated one; can be a mechanical connection or an electrical connection; can be a direct connection or an indirect connection through an intermediate medium, can be the internal connection of two elements or the interaction relationship between two elements; "fix" can be an integrated fixation or a detachable fixation through fasteners; can be a direct fixation or a fixation through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above-mentioned descriptive terms in the present utility model can be understood according to the specific circumstances, the context, the coherence of the context, etc.

[0063] In the present invention, if there are descriptive terms with subsidiary or connecting meanings, for example, a first feature is "on" or "below" a second feature, unless otherwise clearly specified and limited, it should not be understood in a restrictive manner. For example, "on" or "below" may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above descriptive terms in the present invention can be understood according to the specific circumstances, the context, the coherence of the context, etc.

[0064] Furthermore, the first feature being “above”, “above”, and “above” the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being “below”, “below”, and “below” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0065] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments, examples and features of the different embodiments and examples described in this specification without contradiction, and these combinations or combinations shall all fall within the scope summarized by the utility model.

[0066] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are illustrative and cannot be construed as limitations on the present invention. A person skilled in the art can change, modify, replace and modify the above embodiments within the scope of information available from public channels and in combination with the technical inspiration provided by the present application documents.

Claims

1. A suspended front axle hydraulic control system, characterized in that: The invention comprises a front axle oil cylinder (1), a first accumulator (2), a second accumulator (3), a first proportional valve (4), a second proportional valve (5), and an oil replenishing unit, wherein the first accumulator (2) is connected to the first proportional valve (4), and the first proportional valve (4) is connected to the piston rod side of the front axle oil cylinder (1); the second accumulator (3) is connected to the second proportional valve (5), and the second proportional valve (5) is connected to the cylinder body side of the front axle oil cylinder (1); one end of the oil replenishing unit is connected to the piston rod side of the front axle oil cylinder (1), and the other end of the oil replenishing unit is connected to the cylinder body side of the front axle oil cylinder (1).

2. The suspended front axle hydraulic control system according to claim 1 is characterized in that: The oil replenishing unit comprises a first control valve (6), a second control valve (7) and a third control valve (8); one end of the third control valve (8) is provided with a pressure oil port (P); the other end of the third control valve (8) is connected to the first control valve (6) and the second control valve (7) through branches respectively; the first control valve (6) is connected to the piston rod side of the front axle oil cylinder (1), and the second control valve (7) is connected to the cylinder body side of the front axle oil cylinder (1).

3. The suspended front axle hydraulic control system according to claim 2 is characterized in that: The third control valve (8) is an electromagnetic reversing valve, and an oil return port (T) is provided on the third control valve (8); the first control valve (6) and the second control valve (7) are both electromagnetic switch valves.

4. The suspended front axle hydraulic control system according to claim 3 is characterized in that: A first throttle port (10) is also provided on the oil circuit from the first control valve (6) to the front axle oil cylinder (1).

5. The suspended front axle hydraulic control system according to claim 4 is characterized in that: The first throttle port (10) is also connected in parallel with a first one-way valve (11), which enables the hydraulic oil to flow from the first control valve (6) to the piston rod side of the front axle cylinder (1) in one direction.

6. The suspended front axle hydraulic control system according to claim 5, characterized in that: A first pressure gauge (14) is also provided on the oil circuit from the first throttle port (10) to the front axle oil cylinder (1).

7. The suspended front axle hydraulic control system according to claim 3, characterized in that: A second throttle port (12) is also provided on the oil path from the second control valve (7) to the front axle oil cylinder (1).

8. The suspended front axle hydraulic control system according to claim 7, characterized in that: The second throttle port (12) is also connected in parallel with a second one-way valve (13), which enables the hydraulic oil to flow from the second control valve (7) to the cylinder body side of the front axle cylinder (1) in one direction.

9. The suspended front axle hydraulic control system according to claim 8, characterized in that: A second pressure gauge (15) is also provided on the oil circuit from the second throttle port (12) to the front axle oil cylinder (1).

10. The suspended front axle hydraulic control system according to claim 8, characterized in that: A pressure relief branch is also provided on the oil circuit from the second throttle port (12) to the front axle oil cylinder (1), the pressure relief branch is connected to the oil return port (T), and a pressure relief valve (9) is provided on the pressure relief branch.

Images