Lifting valve plate structure, hydraulic lifting control device and counterbalance forklift truck

Abstract

The utility model discloses a lifting valve plate structure, a hydraulic lifting control device and a counterbalance forklift truck. The lifting valve plate structure comprises a valve body, a valve core and a one-way valve, wherein the valve core and the one-way valve are arranged on the valve body; the valve body is provided with an oil inlet channel, an oil return channel, an oil outlet channel and a valve body cavity channel, the valve element is provided with an oil passing groove, and the valve element axially moves relative to the valve body to control whether the oil passing groove is communicated with the oil inlet channel and the oil return channel or not. A spring cavity of the one-way valve is communicated with the valve body cavity channel; the one-way valve controls whether the oil passing groove is communicated with the oil outlet channel or not; the valve element is further provided with a damping channel communicated with the oil passing groove and / or the oil return channel, the valve element controls the damping channel to be communicated with the valve body cavity channel or not by axially moving relative to the valve body, when the oil passing groove is communicated with the oil inlet channel, the damping channel is not communicated with the valve body cavity channel, and when the oil passing groove is communicated with the oil return channel, the damping channel is communicated with the valve body cavity channel. According to the utility model, the one-way valve can be prevented from generating opening impact sound, and the operation micro-motion performance is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of forklifts, in particular to a lifting valve plate structure, a hydraulic lifting control device and a counterbalanced forklift. Background Art

[0002] At present, the lifting valve plate used in the electric counterbalanced forklift of the prior art includes a valve body, a valve core and a logic one-way valve (referred to as one-way valve), the valve body is provided with an oil inlet channel, an oil return channel, an oil outlet channel and a valve body cavity, the valve core is provided with two left and right oil grooves, each of which extends along the circumference of the valve core respectively, and the valve core controls whether the oil groove on the right side is connected with the oil inlet channel and the oil return channel by axial movement relative to the valve body, and controls whether the oil groove on the left side is connected with the oil return channel at the same time, and when the oil groove on the right side of the valve core is connected with the oil inlet channel, the oil groove on the left side of the valve core is not connected with the oil return channel, and when the oil groove on the right side of the valve core is connected with the oil outlet channel, the oil passage of the valve core is connected with the oil return channel; the spring chamber of the one-way valve is connected with the valve body cavity, and the one-way valve controls whether the oil groove of the valve core is connected with the oil outlet channel.

[0003] The above-mentioned lifting valve plate structure of the counterbalanced forklift has the following problems:

[0004] 1. When the logic check valve is operated in a descending condition, the spring chamber of the logic check valve is connected to the oil tank, so the pressure in the spring chamber of the logic check valve is very small; when a heavy load descends, the pressure generated by the load causes a large pressure difference on both sides of the logic check valve. The large pressure difference increases the opening speed and opening force of the logic check valve, thereby generating an opening impact sound. The greater the load, the greater the impact sound, which seriously affects the operating feel.

[0005] Second, the operational stability is poor. When the logic check valve is not opened, the hydraulic oil returns to the oil tank through the damping hole of the logic check valve-the valve body cavity-the oil groove on the left side of the valve core; when the logic check valve is opened, the hydraulic oil returns to the oil tank through the oil groove on the left side of the valve core and the oil groove on the right side. The two oil grooves of the valve core are of the same size. Before and after the logic check valve is opened, the return oil volume is difficult to change linearly. Therefore, at the moment the logic check valve is opened, the speed of the lifting cylinder will have a large gradient change, that is, when the control valve core is in the same position, the descending speed is inconsistent before and after the logic check valve is opened, which affects the micro-motion operation. Utility Model Content

[0006] The utility model aims at the technical problems existing in the prior art and provides a lifting valve plate structure, a hydraulic lifting control device and a counterbalanced forklift, which can avoid the opening impact sound of the one-way valve through structural improvement and improve the micro-movement of operation.

[0007] The technical solution adopted by the utility model to solve its technical problems is: a lifting valve plate structure, including a valve body, and a valve core and a one-way valve arranged on the valve body; the valve body is provided with an oil inlet channel, an oil return channel, an oil outlet channel and a valve body cavity, the valve core is provided with an oil passage groove, and the valve core controls whether the oil passage groove is connected with the oil inlet channel and the oil return channel by axial movement relative to the valve body; the spring chamber of the one-way valve is connected with the valve body cavity, and the one-way valve controls whether the oil passage groove is connected with the oil outlet channel; the valve core is also provided with a damping channel connected with the oil passage groove and / or the oil return channel, and the valve core controls whether the damping channel is connected with the valve body cavity by axial movement relative to the valve body, and when the oil passage groove is connected with the oil inlet channel, the damping channel is not connected with the valve body cavity, and when the oil passage groove is connected with the oil return channel, the damping channel is connected with the valve body cavity.

[0008] Furthermore, the damping channel is arranged along the radial direction of the valve core, and the valve core is also provided with an oil passage channel, and the damping channel is connected to the oil passage groove through the oil passage channel.

[0009] Furthermore, the oil passage includes an axial channel extending along the axial direction of the valve core and at least one radial channel extending along the radial direction of the valve core, the axial channel connects the damping channel and the radial channel, and the radial channel connects the oil passage groove; the inner diameter of the oil passage is larger than the inner diameter of the damping channel.

[0010] Furthermore, there are multiple damping channels, and the multiple damping channels are distributed along the circumference of the valve core.

[0011] Furthermore, the one-way valve is a logical one-way valve, and the sealing plug of the one-way valve is movably fitted between the oil groove and the oil outlet channel, and the outer end face of the sealing plug faces the oil groove, and the side wall of the sealing plug is provided with a damping hole, which connects the spring chamber and the oil outlet channel of the one-way valve.

[0012] Furthermore, the valve body cavity includes a first channel connected to the spring cavity of the one-way valve and a second channel coordinated with the damping channel, and the valve body is connected to a solenoid valve, which controls whether the first channel is connected to the second channel, and the solenoid valve is a normally closed type; the valve body is also provided with a third channel connected to the first channel, and the valve body is also connected to an emergency descent valve, which controls whether the third channel is connected to the oil return channel.

[0013] Furthermore, one end of the valve core is exposed outside the valve body and is used to connect to an operating handle, and a return spring is provided at the other end of the valve core to cause the valve core to automatically return to a neutral position.

[0014] Furthermore, the other end of the valve core is connected to a screw, on which a first limit cover and a second limit cover are movably mounted, and the return spring is fitted between the first limit cover and the second limit cover; it also includes an end cover, which is connected to the valve body and wraps the screw, the first limit cover, the second limit cover and the return spring therein.

[0015] The utility model further provides a hydraulic lifting control device, including a pump motor, a lifting cylinder and an oil tank, wherein the oil inlet of the pump motor is connected to the oil tank; and also includes a lifting valve plate structure as described in the above utility model, wherein the oil outlet of the pump motor is connected to the oil inlet channel, the oil outlet channel is connected to the hydraulic chamber of the lifting cylinder, and the oil return channel is connected to the oil tank.

[0016] The utility model further provides a counterbalanced forklift, comprising the hydraulic lifting control device as described in the utility model.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] The valve core of the utility model adopts a damping channel to replace the oil groove on the left side of the existing valve core. Under the descending condition, the hydraulic oil in the spring chamber of the one-way valve slowly flows to the oil return channel through the damping channel, so that the damping channel will cause the spring chamber of the one-way valve to produce a certain back pressure. In the case of descending with load, the pressure difference on both sides of the one-way valve will not be very large, so that the opening speed and opening force of the one-way valve are both small, so that the one-way valve will not produce an opening impact sound, and the operating experience is better. In addition, the return oil volume of the damping channel is much smaller than the return oil volume of the oil groove on the right side of the valve core, so that before and after the one-way valve is opened, the characteristics of the oil return basically depend on the size of the oil groove on the right side of the valve core. Therefore, the descending linearity of the lifting cylinder is good, relatively stable, and the micro-motion is good.

[0019] Preferably, when the damping channel on the valve core is only connected to the oil groove on the right side of the valve core, the oil return characteristics before and after the one-way valve is opened completely depend on the size of the oil groove on the right side of the valve core, so that the lifting cylinder has a better descending linear speed, no speed gradient, and better micro-motion.

[0020] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments; however, the lifting valve plate structure, hydraulic lifting control device and counterbalanced forklift of the utility model are not limited to the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional view of the lifting valve plate structure of the utility model when the valve core is in the middle position;

[0022] Figure 2 yes Figure 1 A partial enlarged schematic diagram of the one-way valve part;

[0023] Figure 3 It is a cross-sectional view of the lifting valve plate structure of the utility model when the valve core is moved to the left;

[0024] Figure 4 It is a cross-sectional view of the lifting valve plate structure of the utility model when the valve core is moved to the right;

[0025] Figure 5 It is a structural schematic diagram of the hydraulic lifting control device of the utility model;

[0026] In the figure, 1. valve body, 11. oil inlet channel, 12. oil outlet channel, 13. oil return channel, 14. first channel, 15. second channel, 16. third channel, 2. valve core, 21. oil groove, 22. damping channel, 23. axial channel, 24. radial channel, 25. screw, 3. one-way valve, 31. spring chamber, 32. sealing plug, 321. damping hole, 4. solenoid valve, 5. emergency descent valve, 6. reset spring, 7. first limit cover, 8. second limit cover, 9. end cover, 10. oil tank, 20. lifting cylinder. DETAILED DESCRIPTION

[0027] In the present utility model, the terms "first", "second", etc. are only used to distinguish similar objects, rather than to describe a specific order or sequence, and cannot be understood as indicating or implying relative importance. In the description, the directions or positional relationships indicated by "upper", "lower", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present utility model, rather than indicating or implying that the device referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present utility model. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0028] In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0029] See also Figure 1-Figure 4As shown, a lifting valve plate structure of the utility model includes a valve body 1, and a valve core 2 and a one-way valve 3 arranged on the valve body 1; the valve body 1 is provided with an oil inlet channel 11, an oil return channel 13, an oil outlet channel 12 and a valve body cavity, and the right side of the valve core 2 is provided with an oil groove 21 extending along its circumference, and the valve core 2 controls whether the oil groove 21 is connected with the oil inlet channel 11 and the oil return channel 13 by axial movement relative to the valve body 1. Specifically, when the valve core 2 moves to the left to the set position, the oil groove 21 is connected with the oil inlet channel 11; when the valve core 2 moves to the right to the set position, the oil groove 21 is connected with the oil return channel 13; when the valve core 2 returns to the middle position, the oil groove 21 is not connected with the oil inlet channel 11 and the oil return channel 13. The one-way valve 3 is a logic one-way valve, and its spring chamber 31 is connected to the valve body cavity, and the one-way valve 3 controls whether the oil groove 21 of the valve core 2 is connected to the oil outlet channel 12. The left side of the valve core 2 is provided with a damping channel 22 connected to the oil groove 21 and / or the oil return channel 13. The valve core 2 controls whether the damping channel 22 is connected to the valve body cavity by axial movement relative to the valve body 1. When the oil groove 21 is connected to the oil inlet channel 11, the damping channel 22 is not connected to the valve body cavity, and when the oil groove 21 is connected to the oil return channel 13, the damping channel 22 is connected to the valve body cavity.

[0030] Preferably, the damping channel 22 is connected to the oil passage groove 21. Specifically, the valve core 2 is further provided with an oil passage, through which the damping channel 22 is connected to the oil passage groove 21, and the inner diameter of the oil passage groove is larger than the inner diameter of the damping channel 22. The damping channel 22 is arranged along the radial direction of the valve core 2, and the number of the damping channels 22 is multiple, and the multiple damping channels 22 are distributed along the circumference of the valve core 2. The oil passage includes an axial channel 23 extending along the axial direction of the valve core 2 and at least one radial channel 24 extending along the radial direction of the valve core 2, the axial channel 23 connects the damping channel 22 and the radial channel 24, and the radial channel 24 is connected to the oil passage groove 21.

[0031] like Figure 2 As shown, the sealing plug 32 of the one-way valve 3 is movably fitted between the oil groove 21 and the oil outlet channel 12, and the outer end face of the sealing plug 32 faces the oil groove 21. The side wall of the sealing plug 32 is provided with a damping hole 321, which connects the spring chamber 31 of the one-way valve 3 and the oil outlet channel 12.

[0032] In this embodiment, the valve body cavity includes a first channel 14 connected to the spring chamber 31 of the one-way valve 3 and a second channel 15 matched with the damping channel 22. The valve body 1 is connected to a solenoid valve 4, which controls whether the first channel 14 is connected to the second channel 15. The valve body 1 is also provided with a third channel 16 connected to the first channel 14. The valve body 1 is also connected to an emergency descending valve 5, which controls whether the third channel 16 is connected to the return oil channel 13. The above-mentioned solenoid valve 4 is a normally closed type. In the absence of electricity, no matter how it is operated, the lifting cylinder will not descend. The emergency descending valve 5 is used to solve the problem that the lifting cylinder will not descend after the solenoid valve 4 is powered off when the forklift is manually operated. That is, when the solenoid valve 4 fails and the first channel 14 and the second channel 15 cannot be connected after the solenoid valve 4 is energized, causing the lifting cylinder to be unable to descend, the emergency descending valve 5 can be operated to make the first channel 14 connected to the return oil channel 13 through the third channel 16, so that the spring chamber 31 of the one-way valve 3 can be depressurized, and finally the lifting cylinder can be lowered.

[0033] In this embodiment, one end of the valve core 2 is exposed outside the valve body 1 and is used to connect the operating handle. A reset spring 6 is provided at the other end of the valve core 2 to automatically reset the valve core 2 to the middle position. Specifically, a screw 25 is connected to the other end of the valve core 2, and a first limit cover 7 and a second limit cover 8 are movably mounted on the screw 25, and the reset spring 6 is fitted between the first limit cover 7 and the second limit cover 8. The utility model also includes an end cover 9, which is connected to the valve body 1 and wraps the screw 25, the first limit cover 7, the second limit cover 8 and the reset spring 6 therein.

[0034] The utility model is a lifting valve plate structure. When used, the working oil port A of the oil outlet channel 12 of the valve body 1 is connected to the hydraulic chamber of the lifting cylinder 20, the oil return port T of the oil return channel 13 of the valve body 1 is connected to the oil tank 10, the oil inlet port P of the oil inlet channel 11 of the valve body 1 is connected to the oil outlet of the pump motor (not shown in the figure), and the oil inlet port of the pump motor is connected to the oil tank 10. Figure 5 The lifting cylinder 20 is used to drive the mast of the forklift to rise or fall.

[0035] The initial state of the utility model is as follows Figure 1 , Figure 2 As shown, at this time, the valve core 2 is in the middle position, and the one-way valve 3 controls the oil groove 21 of the valve core 2 to be disconnected from the oil outlet channel 12 .

[0036] Lifting condition: When the operator is in normal operation, the solenoid valve 4 is energized, and the solenoid valve 4 becomes a passage state, and the first channel 14 and the second channel 15 of the valve body cavity are connected. When the lifting cylinder 20 needs to be lifted, the valve core 2 moves to the left, so that the oil groove 21 of the valve core 2 is connected with the oil inlet channel 11, and the hydraulic oil from the pump motor flows to the oil groove 21 of the valve core 2 through the oil inlet channel 11. Under the pressure of the hydraulic oil, the sealing plug 32 of the one-way valve 3 is pushed open, so that the oil groove 21 is connected with the oil outlet channel 12, and the hydraulic oil flows to the oil outlet channel 12 and enters the lifting cylinder 20 to achieve the lifting effect, such as Figure 3 During the lifting process, the damping channel 22 of the valve core 2 is not connected to the second channel 15, so the lifting condition is not affected.

[0037] Lowering condition: the valve core 2 moves to the right, so that the oil groove 21 of the valve core 2 is connected with the oil return channel 13, and the damping channel 22 of the valve core 2 is connected with the second channel 15. Therefore, before the one-way valve 3 is opened, the spring chamber 31 of the one-way valve 3 and the first channel 14 and the second channel 15 of the valve body cavity, the damping channel 22, the axial channel 23 and the radial channel 24 of the oil passage act together on the oil return of the oil groove 21; when the load pressure generates a sufficient pressure difference between the two sides of the one-way valve 3 (the valve body cavity and the oil outlet channel 12) through the damping hole 321 of the one-way valve 3, the sealing plug 32 of the one-way valve 3 is pushed open, so that the oil groove 21 is connected with the oil outlet channel 12, the main oil return channel 13 is opened, and the lifting cylinder 20 descends. Figure 4 shown.

[0038] Under the descending condition, before the one-way valve 3 is opened, the cross-sectional area of ​​the damping channel 22 of the valve core 2 is very small, and the oil flows slowly, so that the spring chamber 31 of the one-way valve 3 generates a certain back pressure. When descending with load, the pressure difference on both sides of the one-way valve 3 will not be too large, and the one-way valve 3 will not produce an opening impact sound, so that the operator has a better operating experience. In addition, under the descending condition, the return oil volume of the damping channel 22 is much smaller than the return oil volume of the oil groove 21 on the right side of the valve core 2, so that before and after the one-way valve 3 is opened, the characteristics of the oil return basically depend on the size of the oil groove 21 on the right side of the valve core 2, so the lifting cylinder 20 has good descending linearity, is relatively stable, and has good micro-motion. In particular, in a preferred embodiment, when the valve core 2 moves to the right, the damping channel 22 of the valve core 2 is only connected to the oil groove 21 on the right side of the valve core 2, so that the oil returns through the oil groove 21 of the valve core 2 before and after the one-way valve 3 is opened. Therefore, the characteristics during oil return completely depend on the size of the oil groove 21 on the right side of the valve core 2, thereby making the descending linear speed of the lifting cylinder 20 better, without speed gradient, and with better micro-mobility.

[0039] See also Figure 1-Figure 5As shown, the utility model is a hydraulic lifting control device for a forklift, comprising a pump motor, a lifting cylinder 20 and an oil tank 10, wherein the oil inlet of the pump motor is connected to the oil tank 10; and further comprising a lifting valve plate structure as described above, wherein the oil outlet of the pump motor is connected to the oil inlet channel 11, the oil outlet channel 12 is connected to the hydraulic chamber of the lifting cylinder 20, and the oil return channel 13 is connected to the oil tank 10.

[0040] The utility model provides a hydraulic lifting control device. Regarding the structure and working principle of the lifting valve plate structure, please refer to the above description part thereof, which will not be repeated here.

[0041] The utility model further provides a counterbalanced forklift, comprising the hydraulic lifting control device of the utility model as described above.

[0042] The utility model provides a lifting valve plate structure, a hydraulic lifting control device and a counterbalanced forklift, and the uninvolved parts are the same as the prior art or can be implemented by using the prior art.

[0043] The above embodiments are only used to further illustrate a lifting valve plate structure, a hydraulic lifting control device and a counterbalanced forklift of the utility model, but the utility model is not limited to the embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model fall within the protection scope of the technical solution of the utility model.

Claims

1. A lifting valve plate structure, comprising a valve body, a valve core and a one-way valve arranged on the valve body; the valve body is provided with an oil inlet channel, an oil return channel, an oil outlet channel and a valve body cavity, the valve core is provided with an oil groove, and the valve core controls whether the oil groove is connected with the oil inlet channel and the oil return channel by axial movement relative to the valve body; the spring chamber of the one-way valve is connected with the valve body cavity, and the one-way valve controls whether the oil groove is connected with the oil outlet channel; the characteristics are: The valve core is also provided with a damping channel connected to the oil passage groove and / or the oil return channel. The valve core controls whether the damping channel is connected to the valve body cavity by axial movement relative to the valve body. When the oil passage groove is connected to the oil inlet channel, the damping channel is not connected to the valve body cavity. When the oil passage groove is connected to the oil return channel, the damping channel is connected to the valve body cavity.

2. The lifting valve plate structure according to claim 1, characterized in that: The damping channel is arranged along the radial direction of the valve core, and the valve core is also provided with an oil passage channel, through which the damping channel is connected to the oil passage groove.

3. The lifting valve plate structure according to claim 2, characterized in that: The oil passage includes an axial channel extending along the axial direction of the valve core and at least one radial channel extending along the radial direction of the valve core, the axial channel connects the damping channel and the radial channel, and the radial channel connects the oil passage groove; the inner diameter of the oil passage is larger than the inner diameter of the damping channel.

4. The lifting valve plate structure according to claim 2, characterized in that: There are multiple damping channels, and the multiple damping channels are distributed along the circumference of the valve core.

5. The lifting valve plate structure according to claim 1, characterized in that: The one-way valve is a logical one-way valve, and the sealing plug of the one-way valve is movably fitted between the oil groove and the oil outlet channel, and the outer end face of the sealing plug faces the oil groove. The side wall of the sealing plug is provided with a damping hole, which connects the spring chamber and the oil outlet channel of the one-way valve.

6. The lifting valve plate structure according to any one of claims 1 to 5, characterized in that: The valve body cavity includes a first channel connected to the spring cavity of the one-way valve and a second channel coordinated with the damping channel. The valve body is connected to a solenoid valve, which controls whether the first channel is connected to the second channel, and the solenoid valve is a normally closed type. The valve body is also provided with a third channel connected to the first channel. The valve body is also connected to an emergency descent valve, which controls whether the third channel is connected to the oil return channel.

7. The lifting valve plate structure according to claim 1, characterized in that: One end of the valve core is exposed outside the valve body and is used to connect the operating handle. The other end of the valve core is provided with a reset spring to cause the valve core to automatically reset to the middle position.

8. The lifting valve plate structure according to claim 7, characterized in that: The other end of the valve core is connected to a screw, on which a first limit cover and a second limit cover are movably mounted, and the return spring is fitted between the first limit cover and the second limit cover; it also includes an end cover, which is connected to the valve body and wraps the screw, the first limit cover, the second limit cover and the return spring therein.

9. A hydraulic lifting control device, comprising a pump motor, a lifting oil cylinder and an oil tank, wherein the oil inlet of the pump motor is connected to the oil tank; characterized in that: It also includes a lifting valve plate structure as described in any one of claims 1 to 8, the oil outlet of the pump motor is connected to the oil inlet channel, the oil outlet channel is connected to the hydraulic chamber of the lifting cylinder, and the oil return channel is connected to the oil tank.

10. A counterbalanced forklift, characterized in that: It comprises a hydraulic lifting control device as described in any one of claims 1 to 9.

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