Hydraulic steering device

Abstract

A hydraulic steering device comprises a supply port device with a pressure port and a tank port, a working port device with two working ports, a main flow path with a main orifice and at least one other orifice downstream of the main orifice, the main flow path being arranged between the pressure port and the working port device, a return flow path arranged between the working port device and the tank port, a measuring motor, an amplification flow path with an amplification orifice and arranged between the pressure port and the working port device, and an adjustable pressure source connected to the pressure port and having a load sensing port, wherein a main discharge orifice is connected between the main flow path downstream of the main orifice and the return flow path. The steering device shall have the possibility of dynamic steering with a simple structure. A dynamic main orifice is connected between the load sensing port and the main flow path downstream of the main orifice, and a dynamic discharge orifice is connected between the load sensing port and the return flow path, the dynamic discharge orifice being open when the dynamic main orifice is closed.

Description

Technical Field

[0001] This invention relates to a hydraulic steering device comprising: a supply port device having a pressure port and a tank port; a working port device having two working ports; a main flow path having a main orifice and at least one other orifice downstream of the main orifice, the main flow path being disposed between the pressure port and the working port device; a return flow path disposed between the working port device and the tank port; a measuring motor; an amplifying flow path having an amplifying orifice and disposed between the pressure port and the working port device; and an adjustable pressure source connected to the pressure port and having a load sensing port, wherein a main discharge orifice is connected between the main flow path and the return flow path downstream of the main orifice. Background Technology

[0002] Such hydraulic steering devices are known, for example, from US 2020 / 0114954 A1. In the neutral position, all orifices and amplifying orifices in the main flow path are closed, with the main drain orifice fully open. Hydraulic fluid from the load sensing port of the pressure source is directed to the tank port. Since the flow from the load sensing port of the pressure source is always flowing to the tank port, steering begins as long as the main orifices and amplifying orifices are open. At this time, the main drain orifice is fully closed. Summary of the Invention

[0003] The purpose of this invention is to provide the possibility of dynamic steering with a simple structure.

[0004] This objective is achieved by a hydraulic steering device as described at the beginning of this document, wherein a dynamic main orifice is connected between the load sensing port and the main flow path downstream of the main orifice, and a dynamic discharge orifice is connected between the load sensing port and the return flow path, the dynamic discharge orifice opening when the dynamic main orifice is closed.

[0005] In this configuration, the flow from the load-sensing port of the adjustable pressure source can be used for diversion. This flow, also known as "dynamic flow," is not wasted but instead used for diversion. The dynamic main orifice allows dynamic flow from the load-sensing port of the adjustable pressure source to the tank in a neutral position when all other orifices (potentially except the main discharge orifice) are closed.

[0006] In embodiments of the invention, the dynamic main orifice opens before the main orifice opens. This means that the dynamic flow can be used to make small-angle turns of the steering wheel or steering wheel or any other steering command device. The driver can achieve slow steering, in which only a small dynamic flow is used, rather than the flow through the main orifice in the main road.

[0007] In an embodiment of the invention, the dynamic main orifice is connected to the main flow path between the main orifice and the measuring motor orifice. This means that even dynamic flow is controlled and driven by the measuring motor, so that once the required steering angle of the steering motor has been reached, the measuring motor can be used to stop the steering.

[0008] In an embodiment of the invention, a dynamic amplification orifice is connected between the load sensing port and the main flow path downstream of the measuring motor. Even when using dynamic flow for steering, an amplification factor can be used so that the flow supplied to the steering motor can be increased, and the actions required by the driver (e.g., turning the steering wheel or steering wheel) can be kept small. Because the dynamic amplification orifice is connected to the main flow path downstream of the measuring motor, the dynamic flow guided through the dynamic amplification orifice remains outside the measuring motor.

[0009] In an embodiment of the invention, the dynamically magnifying aperture opens before the main aperture and the magnifying aperture open. This means that steering can begin before both the main aperture and the magnifying aperture open.

[0010] In embodiments of the invention, the opening of the dynamic main orifice is proportional to the opening of the dynamic amplified orifice. Therefore, the dynamic flow through the dynamic amplified orifice is proportional to the flow through the dynamic main orifice. In this way, a constant amplification factor can be established throughout the entire operating range of the hydraulic steering device.

[0011] In an embodiment of the invention, a safety valve is arranged between the dynamic amplification orifice and the main flow path. The safety valve can throttle the flow delivered through the amplification orifice and the dynamic amplification orifice based on the pressure generated by the flow passing through the main orifice and the dynamic main orifice. Furthermore, when the main flow path downstream of the main orifice is blocked, the safety valve can be used to stop the flow supply to the working port device.

[0012] In embodiments of the invention, at least some of the orifices are formed by a valve core and sleeve assembly, wherein the dynamic main orifice and the dynamic amplifying orifice are connected by an annular channel arranged in the sleeve. The annular channel, for example, can connect two dynamic orifices to a load-sensing port of an adjustable pressure source.

[0013] In an embodiment of the invention, the dynamic discharge orifice is connected to the annular channel. This means that the annular channel serves as a collection point for all orifices used for dynamic steering. This simplifies the structure.

[0014] In embodiments of the invention, the relationship between the opening of the main orifice and the opening of the enlarged orifice changes with the actuation speed of the steering command device. When the steering command device is, for example, a steering wheel or steering wheel, the relationship between the opening of the main orifice and the opening of the enlarged orifice changes with the rotational speed of the steering wheel or steering wheel. This means that the enlargement achieved by the enlarged orifice varies with the rotational speed of the steering wheel or steering wheel (or any other actuation speed of the steering command device). Attached Figure Description

[0015] Preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which:

[0016] Figure 1 A schematic diagram of the hydraulic steering system is shown;

[0017] Figure 2 It is the sleeve of the steering unit;

[0018] Figure 3 It is the valve core of the steering unit;

[0019] Figure 4 It is a curve showing the opening degree of the orifice of the steering device according to the angle deflection between the valve core and the sleeve. Detailed Implementation

[0020] The hydraulic steering system 1 includes a supply port device with a pressure port P and a gearbox port T. Furthermore, the steering system 1 includes a working port device with a left working port L and a right working port R. A main flow path 2 is arranged between the pressure port P and the working port devices L and R. Which of the two working ports L and R is connected to the main flow path 2 depends on the steering direction.

[0021] Main flow path 2 includes a main orifice A1 and a measuring motor 3. A first measuring motor orifice A2 is located upstream of the measuring motor 3, and a second measuring motor orifice A3 is located downstream of the measuring motor 3. The terms "upstream" and "downstream" relate to the flow direction from the pressure port P to the working port devices L and R.

[0022] The return flow path 4 is arranged between the working port devices L and R and the box port T. Similarly, which of the working ports L and R is connected to the return flow path 4 depends on the direction of rotation.

[0023] Hydraulic fluid traveling through the main flow path 2 is supplied to one of the working ports L and R via working port orifice A4, and hydraulic fluid returning through the other working port R or L flows into the return flow path 4 via the other working port orifice A5. Similarly, which of the working port orifices A4 and A5 is used for supply and return flow depends on the direction of rotation.

[0024] Main discharge port A drain Point 5 is located between the main flow path 2 and the return flow path 4. Point 5 is located downstream of the main orifice A1 and upstream of the first measuring motor orifice A2.

[0025] The steering device 1 also includes an amplifying flow path 6 with an amplifying orifice AU. The amplifying flow path 6 is arranged between the pressure port P and the working port devices L and R. The amplifying flow path 6 is connected to the main flow path 2 at point 7 between the second measuring motor orifice A3 and the working port orifice A4. The working port orifices A4 and A5 are sized such that they can take over the combined flow of the main flow path 2 and the amplifying flow path 6.

[0026] Orifices A1-A5, AU, and Adrain are formed, for example, in the spool / sleeve assembly, wherein the spool 26 and sleeve 27 ( Figure 2 and Figure 3 The valve core 26 and sleeve 27 are arranged rotatably relative to each other. One of them, valve core 26 and sleeve 27, is connected to the steering wheel (not shown), and the other is connected to the measuring motor 3. Valve core 26 and sleeve 27 together define the aforementioned orifice. When valve core 26 rotates relative to sleeve 27, the main discharge orifice Adrain begins to throttle, i.e., the flow area of ​​the main discharge orifice Adrain decreases. As valve core 26 rotates further relative to sleeve 27, i.e., as the deflection between valve core 26 and sleeve 27 increases, orifices A2-A5 and AU begin to open, allowing hydraulic fluid to flow from pressure port P to one of the working ports L and R. This flow drives the measuring motor 3. The measuring motor 3 is operably connected to another part of the valve core / sleeve assembly that is not connected to the steering wheel or steering wheel, and once the required amount of hydraulic fluid has been supplied to the working port device, the measuring motor 3 rotates the steering wheel or steering wheel back to its initial position.

[0027] However, only after the main discharge orifice Adrain has begun to throttle will the main orifice A1 and the enlarged orifice AU begin to open at the same angle as the steering wheel or steering column. The opening of the main orifice A1 and the opening of the enlarged orifice AU can be proportional to each other. This proportion defines the amplification factor that should be obtained using the enlarged flow path 6. For example, when the opening of the enlarged orifice AU increases faster than the opening of the main orifice A1, more than 100% of the fluid traveling through the main flow path 2 travels through the enlarged flow path 6, except for the section 8 between point 7 and the working port L.

[0028] Figure 4 The diagram shows the opening degree of the corresponding orifice, which depends on the deflection between the valve core 26 and the sleeve 27. This deflection depends on the rotational speed of the steering wheel or steering wheel. The higher the rotational speed of the steering wheel or steering wheel, the greater the deflection.

[0029] It can be seen that, Figure 4 In the illustrated embodiment, the opening of the main orifice A1 and the opening of the enlarged orifice AU are not proportional to each other. This means that the amplification factor changes with the deflection between the valve core 26 and the sleeve 27, and thus with the rotational speed of the steering wheel or steering wheel.

[0030] In addition, it should be noted that, Figure 4 In the illustrated embodiment, the dynamic master orifice A1-dyn and the dynamic enlarged orifice AU-dyn open substantially proportionally to each other. The openings of these two orifices, A1-dyn and AU-dyn, are the same for all deflection angles. However, non-proportional relationships can also be used between the openings of the dynamic orifices.

[0031] The steering device 1 includes an adjustable pressure source 9. The pressure source 9 includes a pump 10, which may have a fixed displacement, and the pump 10 is driven by the motor or engine of the vehicle to be steered via a shaft 11.

[0032] Pump 10 is connected to inlet 13 of pilot valve 12. Pilot valve 12 includes piston 14 disposed between pressure chamber 15 and spring chamber 16. Spring 17 is disposed in spring chamber 16.

[0033] The pilot valve 12 includes a pilot outlet CF and another outlet EF that can be connected to additional hydraulic equipment (not shown).

[0034] The lead-out port CF is connected to the pressure chamber 15 via the orifice APP. The lead-out port CF is also connected to the spring chamber 16 via the dynamic orifice Adyn. The piston 14 is assumed to be in a position where the force generated by the pressure difference between the pressure chamber 15 and the spring chamber 16 is balanced by the force of the spring 17.

[0035] Pilot valve 12 includes a load sensing port 18 connected to a load sensing orifice ALS. Load sensing port 18 is connected to main flow path 2 at point 19 downstream of main orifice A1 via load sensing orifice ALS (which is a fixed orifice) and dynamic main orifice A1-dyn. Point 19 may be the same as point 5. Dynamic main orifice A1-dyn opens before main orifice A1 opens. Dynamic main orifice A1-dyn connects to main flow path 2 between main orifice A1 and measuring motor orifice A2.

[0036] The load sensing port 18 of the adjustable pressure source 9 is connected to the amplification flow path 6 via the load sensing orifice ALS and the dynamic amplification orifice AU-dyn, and is also connected to point 7 in the main flow path 2 via the amplification flow path 6. The dynamic amplification orifice AU-dyn is opened before the amplification orifice AU is opened.

[0037] As mentioned above, the opening degree of the dynamic main orifice A1-dyn is proportional to the opening degree of the dynamic amplifying orifice AU-dyn. This means that as long as the main orifice A1 and the amplifying orifice AU are closed, the dynamic flow from the load sensing port 18 will be proportionally divided and supplied to the measuring motor 3 via the main flow path 2, and to point 7 via the amplifying flow path 6. The load sensing port 18 is connected to point 20 between the dynamic main orifice A1-dyn and the dynamic amplifying orifice AU-dyn. Point 20 is connected to the box port T via the dynamic discharge orifice Adrain-dyn. When the dynamic main orifice A1-dyn and the dynamic amplifying orifice AU-dyn are closed, the dynamic discharge orifice Adrain-dyn is open.

[0038] Point 20 can be arranged in the annular channel 28 of sleeve 27 ( Figure 2 The annular channel 28 can be connected to the load sensing port 18 of the adjustable pressure source 9.

[0039] Safety valve 21 is arranged in amplifying flow path 6. Safety valve 21 includes valve element 22, which is, for example, in the form of a ball. Valve element 22 is subjected to pressure in amplifying flow path 6 in the opening direction and to the force of spring 23 and pressure at point 5 in the main flow path 2 downstream of main orifice A1 in the closing direction.

[0040] When no steering is intended, the steering mechanism is in neutral. In neutral, all orifices and the enlarged orifice AU in the main flow path 2 are closed. In addition, the dynamic main orifice A1-dyn and the dynamic enlarged orifice AU-dyn are also closed, and the dynamic discharge orifice Adrain-dyn is open, thereby guiding the dynamic flow from the load sensing port 18 of the pressure source 9 to the box T.

[0041] When the driver moves the steering wheel or steering wheel (not shown) or any other steering command device by only a small angle, such as when steering begins, the dynamic main orifice A1-dyn and the dynamic amplifying orifice AU-dyn open. In this case, there is only a small angular deflection between the valve core 26 and the sleeve 27. The dynamic discharge orifice Adrain-dyn remains open, however, throttling begins. Thus, the dynamic flow from the load sensing port 18 can be used to generate a hydraulic fluid supply to the working port devices L, R. A portion of the hydraulic fluid is supplied through the main flow path 2 and passes through the measuring motor 3 so that steering can be terminated once the desired steering angle has been reached. The remaining portion of the dynamic flow passes through the dynamic amplifying orifice AU-dyn and is supplied via the safety valve 21 to point 7 between the measuring motor orifice A3 and the working port orifice A4. The flow rate through the dynamic amplifying orifice AU-dyn will be the same as, or 2, 3, or 4 times higher than, the flow rate through the dynamic main orifice A1-dyn. As the rotational speed of the steering wheel or steering wheel (or any other steering command device) and the corresponding deflection between the valve core 26 and sleeve 27 further increase, the main orifice A1 and the amplified orifice AU open, and the dynamic discharge orifice Adrain-dyn closes. The main discharge orifice Adrain also closes. Therefore, the hydraulic fluid supplied from the outlet CF of the pilot valve 12 is fully supplied to the working port devices L, R, wherein a portion of this hydraulic flow is supplied via the main flow path A1 and measured by the measuring motor 3, and another portion of this flow is supplied via the amplified flow path 6 without passing through the measuring motor 3.

[0042] There are still flows through the dynamic main orifice A1-dyn and through the dynamic enlarged orifice AU-dyn.

[0043] Instead of the combination of pump 10 with a fixed displacement and pilot valve 12, a pump with a variable displacement, which is capable of generating dynamic flow, can also be used.

[0044] The overpressure valve 24 connects the load sensing line 25 to the tank. The load sensing line 25 connects the load sensing port 18 to point 20, i.e., to the dynamic orifices A1-dyn, AU-dyn, and Adrain-dyn, and the load sensing line 25 includes the load sensing orifice ALS.

Claims

1. A hydraulic steering device (1), comprising: A supply port device having a pressure port (P) and a tank port (T); A working port device (L, R) with two working ports; a main flow path (2) having a main orifice (A1) and at least one other orifice (A2, A3, A4) downstream of the main orifice (A1), the main flow path (2) being arranged between the pressure port (P) and the working port device (L, R); a return flow path (4) arranged between the working port device (L, R) and the box port (T); a measuring motor (3); and a magnifying orifice (A... U ) and an amplified flow path (6) arranged between the pressure port (P) and the working port device (L, R); and an adjustable pressure source (9) connected to the pressure port (P) and having a load sensing port (18), wherein the main discharge port (A drain The main flow path (2) downstream of the main orifice (A1) and the return flow path (4) are connected, characterized in that the dynamic main orifice (A1-dyn) is connected between the load sensing port (18) and the main flow path (2) downstream of the main orifice (A1), and the dynamic discharge orifice (Adrain-dyn) is connected between the load sensing port (18) and the return flow path (4), wherein the dynamic discharge orifice (Adrain-dyn) opens when the dynamic main orifice (A1-dyn) is closed.

2. The hydraulic steering device according to claim 1, characterized in that, The dynamic master orifice (A1-dyn) opens before the master orifice (A1) opens.

3. The hydraulic steering device according to claim 1 or 2, characterized in that, The dynamic main orifice (A1-dyn) is connected to the main flow path (2) between the main orifice (A1) and the measuring motor orifice (A2).

4. The hydraulic steering device according to claim 1 or 2, characterized in that, The dynamic amplification orifice (AU-dyn) is connected between the load sensing port (18) and the main flow path (2) downstream of the measuring motor (3).

5. The hydraulic steering device according to claim 4, characterized in that, The dynamic magnifying aperture (A1-dyn) opens before the magnifying aperture (AU) opens.

6. The hydraulic steering device according to claim 4, characterized in that, The opening of the dynamic main orifice (A1-dyn) is proportional to the opening of the dynamic enlarged orifice (A4-dyn).

7. The hydraulic steering device according to claim 4, characterized in that, The safety valve (21) is arranged between the dynamic amplification orifice (A1-dyn) and the main flow path (2).

8. The hydraulic steering device according to claim 4, characterized in that, At least some of the orifices are formed by a device of valve core (26) and sleeve (27), wherein the dynamic main orifice (A1-dyn) and the dynamic amplified orifice (AU-dyn) are connected by means of an annular channel (28) arranged in the sleeve (27).

9. The hydraulic steering device according to claim 8, characterized in that, The dynamic discharge port (Adrain-dyn) is connected to the annular channel (28).

10. The hydraulic steering device according to claim 1, characterized in that, The opening of the main orifice (A1) and the enlarged orifice (A) U The relationship between the opening degree of the steering command device changes with the actuation speed of the steering command device.

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