Load control valve

Abstract

The utility model provides a load control valve, which is used for controlling a variable displacement mechanism of a swash plate type variable displacement pump and comprises a valve body, a working port A, a working port B and a control port P connected with a pilot control oil way are arranged on the valve body, a monitoring port communicated with and used for monitoring pressure of a working oil way is further arranged on the valve body, and a valve hole is arranged on the valve body. A valve element is arranged in the valve hole in a sliding mode, a mounting hole is formed in a right hole opening of the valve hole, and an adjusting mechanism is arranged in the mounting hole. A left control cavity is formed in a left hole opening of the valve hole; the left control cavity is communicated with the control port P, the monitoring port is communicated with the mounting hole, the working state of the valve element is controlled through the pressure of the control port P, the pressure of the monitoring port and the pressure of the adjusting mechanism together, the position of the valve element can be changed through the changed pressure of the monitoring port, and then the purpose of controlling the dip angle change of the hydraulic pump swash plate is achieved. The pressure of the monitoring port directly controls the inclination angle state of the swash plate, and the corresponding speed is high.

Description

Technical Field

[0001] The utility model relates to the hydraulic field, in particular to a load control valve. Background Art

[0002] The hydraulic pump is the core component of the hydraulic system and provides power source for the hydraulic system. The main pump of the existing excavator is mainly an electric K3V hydraulic pump. During use, when the load demand is large, the inclination angle of the hydraulic pump swash plate is at a larger angle, so that the displacement of the hydraulic pump is in a larger state. When the load demand is small, the inclination angle of the hydraulic pump swash plate is at a smaller angle, reducing the displacement of the hydraulic pump and reducing energy loss.

[0003] The existing K3V hydraulic pump controls the inclination angle of the swash plate through a load-sensitive valve to control the flow of the hydraulic pump. Therefore, the control response speed and reliability of the load-sensitive valve directly affect the adjustment characteristics and energy-saving performance of the hydraulic pump. The existing load-sensitive valve slide valve structure uses spring adjustment and reset. Due to the deflection of the spiral spring force and the surface contact of the action surface, the valve core moves slowly or even gets stuck, and there are problems such as slow response speed and delayed regulation. Utility Model Content

[0004] The technical problem to be solved by the utility model is that the valve core of the existing load control valve moves slowly and has a slow response speed. The utility model provides a load control valve to solve the above problem.

[0005] The utility model solves the technical problem by adopting the following technical scheme: a load control valve, used for controlling the variable mechanism of a swash plate type variable pump, comprises a valve body, the valve body is provided with a working port A, a working port B and a control port P connected to a pilot control oil circuit, the working port A and the working port B are respectively connected to the inlet and the outlet of the swash plate angle oil cylinder of the variable mechanism, the valve body is also provided with a monitoring port for communicating with the pressure of the monitoring working oil circuit, the valve body is provided with a valve hole, a valve core is slidably arranged in the valve hole, a mounting hole is arranged at the right orifice of the valve hole, and an adjusting mechanism is arranged in the mounting hole; a left control chamber is arranged at the left orifice of the valve hole, the control port P, the working port A and the working port B are arranged along the valve hole in sequence; when the valve core is in the right position, the control port P is connected to the working port A; when the valve core is in the left position, the working port A is connected to the working port B; the left control chamber is connected to the control port P, and the monitoring port is connected to the mounting hole.

[0006] Further: the regulating mechanism comprises a top seat, a spring and an adjusting push rod, the top seat and the spring are installed in the mounting hole and the spring pushes the top seat toward the valve core;

[0007] A ball hole is provided on the top seat at the end surface near the valve core, a ball is installed in the ball hole, and the ball is attached to the end surface of the valve core near the top seat.

[0008] Furthermore: a mounting thread is provided at the opening of the mounting hole, and an external thread screwed onto the mounting thread is provided on the outer wall of the adjusting push rod; an inner hexagonal hole is provided on the outer end surface of the adjusting push rod, and a positioning step is provided on the inner end surface, and the spring is sleeved on the outside of the positioning step.

[0009] The beneficial effect of the utility model is that the load control valve of the present application controls the working state of the valve core through the pressure of the control port P, the monitoring port and the regulating mechanism. The position of the valve core can be changed by the pressure change of the monitoring port, thereby achieving the purpose of controlling the change of the inclination angle of the swash plate of the hydraulic pump. The pressure of the monitoring port directly controls the inclination state of the swash plate, and the response speed is fast. The top seat and the valve core are in contact with the ball, which improves the force environment of the end face of the valve core, avoids the generation of adverse external forces such as lateral pressure on the valve core, reduces the occurrence of valve core jamming, improves the sensitivity of the valve core action, shortens the reaction time, and also avoids the problems of short life caused by eccentric wear of the valve core. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0011] Figure 1 It is a structural cross-sectional schematic diagram of a load control valve of the utility model;

[0012] Figure 2 yes Figure 1 A partial enlarged view of point A in the figure.

[0013] In the figure, 1, valve body, 2, working port A, 3, working port B, 4, control port P, 5, monitoring port, 6, valve hole, 7, valve core, 8, mounting hole, 9, left control chamber, 10, top seat, 11, spring, 12, adjusting push rod, 13, ball hole, 14, ball, 15, mounting thread, 16, external thread, 17, hexagonal hole, 18, positioning step. DETAILED DESCRIPTION

[0014] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0015] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0016] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, in the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0017] Any process or method description in the flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0018] like Figure 1 and Figure 2As shown, the utility model provides a load control valve for controlling a variable mechanism of a swash plate type variable pump, comprising a valve body 1, the valve body 1 is provided with a working port A2, a working port B3 and a control port P4 connected to a pilot control oil circuit, the working port A2 and the working port B3 are respectively connected to the inlet and outlet of the swash plate angle cylinder of the variable mechanism, the valve body 1 is also provided with a monitoring port 5 for communicating with monitoring the pressure of the working oil circuit, the valve body 1 is provided with a valve hole 6, a valve core 7 is slidably provided in the valve hole 6, and a valve core 7 is slidably provided in the valve hole A mounting hole 8 is provided at the right orifice of the valve hole 6, and an adjusting mechanism is provided in the mounting hole 8; a left control chamber 9 is provided at the left orifice of the valve hole 6, and the control port P4, the working port A2 and the working port B3 are sequentially arranged along the valve hole 6; when the valve core 7 is in the right position, the control port P4 is communicated with the working port A2; when the valve core 7 is in the left position, the working port A2 is communicated with the working port B3; the left control chamber 9 is communicated with the control port P4, and the monitoring port 5 is communicated with the mounting hole 8.

[0019] In the present application, the left and right position state of the valve core 7 in the valve hole 6 is controlled by the pressure of the control port P4, the monitoring port 5 and the regulating mechanism. The position of the valve core 7 can be changed by the pressure change of the monitoring port 5, thereby changing the state of the oil inlet and outlet of the working port A2 and the working port B3, and then controlling the action of the variable mechanism, so as to monitor the load according to the pressure of the monitoring port 5, and timely adjust the output mode of the swash plate variable pump to obtain timely variable output and improve energy utilization efficiency.

[0020] The adjustment mechanism includes a top seat 10, a spring 11 and an adjusting push rod 12. The top seat 10 and the spring 11 are installed in the installation hole 8, and the spring 11 pushes the top seat 10 toward the valve core 7. On the top seat 10, a ball hole 13 is provided at the end surface near the valve core 7, and a ball 14 is installed in the ball hole 13. The ball 14 fits on the end surface of the valve core 7 near the top seat 10.

[0021] The valve core 7 in the valve body 1 slides in the valve hole 6, so that the different on-off states of the oil circuit on the valve body 1 can be switched. The top seat 10 is pushed and fitted onto the end face of the valve core 7 by the spring 11 of the adjustment mechanism, which can generate positive pressure on the end face of the valve core 7. The pushing action of the top seat 10 on the end face of the valve core 7 and other forces acting on the end face of the valve core 7 can jointly control the sliding state of the valve core 7.

[0022] In the present application, the end face of the top seat 10 and the end face of the valve core 7 are not fitted together in the way of end face and end face fitting in the prior art, but a ball 14 is installed on the end face of the top seat 10, and the ball 14 is fitted on the end face of the valve core 7, and the end face of the valve core 7 is pushed by the ball 14.

[0023] On the one hand, after the original end-face-to-end-face fit is changed to the spherical-face-to-end-face fit, when the spring 11 applies thrust to the tilted top seat 10, it will not directly act on the valve core 7, but will always maintain positive pressure on the end face of the valve core 7 through the follow-up adjustment ability of the ball 14, thereby avoiding the generation of adverse external forces such as lateral push on the valve core 7, reducing the occurrence of valve core 7 jamming, improving the sensitivity of the valve core 7, shortening the reaction time, and avoiding problems such as short life due to eccentric wear of the valve core 7.

[0024] On the other hand, the ball 14 can roll freely on the end face of the valve core 7 and adjust its position adaptively, which can eliminate some assembly or manufacturing errors. Even if there is a small amount of misalignment between the center of the valve core 7 and the center of the adjustment mechanism, it will not affect the normal operation and working performance of the valve core 7.

[0025] Through the above modification, the common problems in the existing spring 11 structure adjustment mechanism, such as eccentric wear of the valve core 7, stagnation of the valve core 7 movement, slow response caused by the valve core 7 pushing out of the same axis, and even the valve core 7 being stuck in the valve hole 6, are overcome. The force environment of the valve core 7 is improved, adverse external forces are avoided, the response time of the valve core 7 is shortened, and the operating life of the hydraulic system is extended.

[0026] A mounting thread 15 is provided at the opening of the mounting hole 8, and an external thread 16 screwed onto the mounting thread 15 is provided on the outer wall of the adjusting push rod 12; an inner hexagonal hole 17 is provided on the outer end surface of the adjusting push rod 12, and a positioning step 18 is provided on the inner end surface thereof, and the spring 11 is sleeved on the outside of the positioning step 18.

[0027] By turning the hexagonal hole 17, the push rod 12 can be screwed and adjusted, so that the pre-tightening force of the push rod 12 on the spring 11 can be adjusted to adjust the control state of the valve core 7. The positioning step 18 can be engaged with the inner ring of the spring 11, which plays a preliminary guiding and positioning role for the spring 11, ensuring that the spring 11 can be compressed and expanded in a vertical state, avoiding abnormalities such as compression deviation and deflection, and improving the reliability of the hydraulic valve.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without deviating from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A load control valve for controlling a variable mechanism of a swash plate type variable displacement pump, comprising a valve body (1), the valve body (1) being provided with a working port A (2), a working port B (3) and a control port P (4) connected to a pilot control oil circuit, the working port A (2) and the working port B (3) being connected to an inlet and an outlet of a swash plate angle cylinder of the variable mechanism, respectively, and characterized in that: The valve body (1) is also provided with a monitoring port (5) for communicating with and monitoring the pressure of the working oil circuit. The valve body (1) is provided with a valve hole (6), in which a valve core (7) is slidably arranged. A mounting hole (8) is provided at the right opening of the valve hole (6), and an adjustment mechanism is provided in the mounting hole (8). A left control chamber (9) is provided at the left opening of the valve hole (6), and the control port P (4), the working port A (2) and the working port B (3) are arranged in sequence along the valve hole (6). When the valve core (7) is in the right position, the control port P (4) is communicated with the working port A (2); when the valve core (7) is in the left position, the working port A (2) and the working port B (3) are communicated. The left control chamber (9) is communicated with the control port P (4), and the monitoring port (5) is communicated with the mounting hole (8).

2. A load control valve according to claim 1, characterized in that: The regulating mechanism comprises a top seat (10), a spring (11) and an regulating push rod (12); the top seat (10) and the spring (11) are installed in the installation hole (8), and the spring (11) pushes the top seat (10) toward the valve core (7); A ball hole (13) is provided on the top seat (10) at the end surface near the valve core (7), a ball (14) is installed in the ball hole (13), and the ball (14) is attached to the end surface of the valve core (7) near the top seat (10).

3. A load control valve according to claim 2, characterized in that: The mounting hole (8) is provided with a mounting thread (15) at its opening, and the outer wall of the adjusting push rod (12) is provided with an external thread (16) screwed onto the mounting thread (15); the outer end surface of the adjusting push rod (12) is provided with a hexagonal hole (17), and the inner end surface thereof is provided with a positioning step (18), and the spring (11) is sleeved on the outside of the positioning step (18).

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