Force feedback control variable mechanism

Abstract

The utility model discloses a force feedback control variable mechanism which is characterized by comprising a valve element arranged in a valve body, a servo plunger is arranged between the valve element and the valve body, one end of the valve element is inserted in a spring seat and movably connected with the spring seat, the other end of the valve element is matched with a valve sleeve, the valve sleeve is connected with a fixing block on the outer side of the valve body, and an electromagnet is arranged on the outer side of the fixing block. The electromagnet is matched with the valve element penetrating through the valve sleeve. The spring seat is exposed out of the valve body, and the exposed part is connected with the adjusting screw in an inserted mode. The shifting fork is exposed out of a cavity in the side face of the valve body. A supporting rod is arranged on the valve element in a penetrating mode, and the portion, between the supporting rod and the servo plunger, of the valve element is sleeved with a control spring. The variable control mode is achieved through feedback of spring force, the requirement for the machining precision of parts is not high, but accurate displacement control can be achieved; different pre-tightening forces are set for the adjusting screw rod, so that the same current and different displacement output can be realized, and diversified control variable characteristics are easy to realize.

Description

Technical Field

[0001] The utility model relates to a force feedback control variable mechanism, belonging to the application field of hydraulic plunger pump technology. Background Art

[0002] The control variable mechanism is an important structural unit of the axial hydraulic piston pump. Because of the existence of the control variable mechanism, the piston pump can adjust the flow output according to the external load signal. This kind of piston pump that can adjust the output flow according to the external load signal is called a variable piston pump. If there is no control variable mechanism, the output flow of the piston pump will not change with the change of the external signal, so it is called a fixed-displacement pump. The presence or absence of a control variable mechanism is also the main sign to distinguish between a fixed-displacement pump and a variable pump.

[0003] In order to reduce energy consumption, most construction machinery uses variable displacement piston pumps. In the design of variable displacement piston pumps, the mainstream traditional displacement feedback control variable mechanism uses the displacement feedback adjustment mechanism designed and produced by Kawasaki Heavy Industries of Japan. Its structure is as follows: Figure 1 As shown, the control principle is briefly described as follows: the position of the U-shaped groove at the lower end of the fork 16 receives the left and right displacement signal of the swash plate swing angle of the plunger pump. The fork 16 uses the fixed pin 15 as a fulcrum to pull the valve core 11 to move left and right in the valve sleeve 10. The valve sleeve 10 is fixed to the valve body 14 by a retaining spring. The movement of the valve core 11 controls the connection and disconnection of the hydraulic oil passages P and A. When P and A are connected, the displacement of the variable plunger pump decreases, and when P and A are disconnected, the displacement of the plunger pump increases, thereby realizing the control variable function. Through the structural principle analysis, it can be seen that the swash plate swing displacement signal received by the fork 16 is directly and rigidly fed back to the valve core 11, and the variable is controlled by the movement of the valve core 11.

[0004] If this design is to achieve high-precision control variables, the processing accuracy of related parts is required to be high, and the design and manufacturing costs will also increase accordingly; secondly, in this design, after the relative positions of the pin hole fulcrum are determined, the characteristics of the control variables are also relatively determined, which cannot meet the requirements of diversified control variable characteristics. Therefore, the variable mechanism of this design has great limitations in terms of processing difficulty, cost control, and diversified variable characteristic requirements. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide a force feedback control variable mechanism to solve the problems of high processing accuracy and single control variable characteristic output faced by the existing displacement feedback control variable mechanism.

[0006] In order to solve the above problems, the technical solution of the utility model provides a force feedback control variable mechanism, which is characterized in that it includes a valve core arranged in a valve body, a servo plunger is arranged between the valve core and the valve body, one end of the valve core is inserted in a spring seat and movably connected, and the other end cooperates with a valve sleeve, and the valve sleeve is provided with two channels, the valve sleeve is connected to a fixed block on the outside of the valve body, an electromagnet is arranged on the outside of the fixed block, and the electromagnet cooperates with the valve core passing through the valve sleeve; a spring is arranged in the spring seat, the spring seat is exposed from the valve body, and the exposed part is plugged into the adjusting screw; the servo plunger is provided with a ring groove for cooperating with a shift fork, and the shift fork is exposed from the cavity on the side of the valve body; a support rod is passed through the valve core, and a control spring is arranged on the valve core sleeve between the support rod and the servo plunger.

[0007] Preferably, the adjusting screw is coaxially arranged with the valve core.

[0008] Preferably, a cap is provided at the outer end of the adjusting screw.

[0009] More preferably, a nut for tightening and sealing the adjusting screw is provided between the cap and the spring seat.

[0010] Preferably, the spring seat sleeve is provided with a nut for adjusting the preload of the spring.

[0011] Preferably, a fixing pin is provided in the cavity on the side of the valve body, and the fixing pin is passed through the shift fork to serve as a fulcrum for the rotation of the shift fork.

[0012] Preferably, a shoulder for limiting position is provided on one side of the valve sleeve, and the shoulder is fixedly connected to the fixing block and the valve body by screws; the fixing block is connected to the electromagnet by threads.

[0013] Preferably, the valve core and the valve sleeve are nested with each other, one end of the valve core is in contact with the armature end face of the electromagnet, and the other end is matched with the support rod through a hemisphere.

[0014] Preferably, the ball head portion of the shift fork cooperates with the annular groove of the servo plunger, and the fixing pin is arranged in a cavity on the side of the valve body to serve as a fulcrum for the rotation of the shift fork.

[0015] Preferably, a port of the first channel on the valve sleeve close to the servo plunger is port P, another port of the second channel close to the fixed block relative to port P is port A, and the U-shaped groove of the shift fork exposed from the valve body is a position for receiving external signal feedback.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] 1. The machining accuracy requirement is low, the manufacturing cost is controllable, and the precise control variable characteristics are easy to achieve;

[0018] 2. It is easy to realize the output of various control variable characteristics and has stronger applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the traditional displacement feedback control variable mechanism;

[0020] Figure 2 , 3 A schematic diagram of the structure of the force feedback control variable mechanism in different states provided by the utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the utility model installed in a plunger pump. DETAILED DESCRIPTION

[0022] In order to make the present invention more obvious and easy to understand, preferred embodiments are described in detail as follows in conjunction with the accompanying drawings.

[0023] Example

[0024] like Figure 2-3 As shown, a force feedback control variable mechanism provided by the utility model is characterized in that it includes a valve core 11 arranged in a valve body 14, a servo plunger 9 is arranged between the valve core 11 and the valve body 14, one end of the valve core 11 is inserted in a spring seat 5 for active connection, and the other end cooperates with a valve sleeve 10, and the valve sleeve 10 is provided with two channels, the valve sleeve 10 is connected to a fixed block 12 on the outside of the valve body 14, an electromagnet 13 is arranged on the outside of the fixed block 12, and the electromagnet 13 cooperates with the valve core 11 passing through the valve sleeve 10; a spring 6 is arranged in the spring seat 5, and the spring seat 5 is exposed from the valve body 14, and the exposed part is plugged into the adjusting screw 2; the servo plunger 9 is provided with an annular groove for cooperating with a shift fork 16, and the shift fork 16 is exposed from the cavity on the side of the valve body 14; a support rod 7 is passed through the valve core 11, and a control spring 8 is arranged on the outer sleeve of the valve core 11 between the support rod 7 and the servo plunger 9.

[0025] The adjusting screw 2 is coaxially arranged with the valve core 11 .

[0026] The outer end of the adjusting screw 2 is provided with a cap 1. A nut 4 for tightening and sealing the adjusting screw 2 is provided between the cap 1 and the spring seat 5.

[0027] The spring seat 5 is covered with a nut 3 for adjusting the preload of the spring 6 .

[0028] A fixing pin 15 is provided in the cavity on the side of the valve body 14 . The fixing pin 15 penetrates into the shift fork 16 and serves as a fulcrum for the rotation of the shift fork 16 .

[0029] A shoulder for limiting position is provided on one side of the valve sleeve 10 , and the shoulder is fixedly connected to the fixing block 12 and the valve body 14 by screws; the fixing block 12 is connected to the electromagnet 13 by threads.

[0030] The valve core 11 and the valve sleeve 10 are nested with each other, one end of the valve core 11 contacts the armature end face of the electromagnet 13, and the other end cooperates with the support rod 7 through a hemisphere.

[0031] The ball head portion of the shift fork 16 matches with the annular groove of the servo plunger 9 , and the fixing pin 15 is disposed in a cavity on the side of the valve body 14 , serving as a fulcrum for the rotation of the shift fork 16 .

[0032] One port of the first channel 17 on the valve sleeve 10 close to the servo plunger 9 is the P port, and the other port of the second channel 18 close to the fixed block 12 relative to the P port is the A port. The U-shaped fork of the fork 16 exposed from the valve body 14 is the external signal feedback receiving position 19.

[0033] like Figure 4 As shown, the force feedback control variable mechanism is fixed on the plunger pump by screw locking, and the fork 16 cooperates with the cylindrical pin inside the plunger pump to receive the signal from the displacement change of the plunger pump. When the swash plate angle of the plunger pump changes, the cylindrical pin moves up and down to drive the fork 16 to rotate around the fixed pin 15. The spherical surface of the other end of the fork 16 is installed in the annular groove of the servo plunger 9. When the ball head of the fork 16 rotates around the fixed pin 15, it will compress or release the control spring 8. The change of the spring force will affect the on-off of P and A, thereby controlling the output of the displacement of the plunger pump.

[0034] The principle of a force feedback control variable provided by the utility model is as follows:

[0035] By adjusting the screw 2 to set the preload F1 on the spring 6, F1 forms a force on the support rod 7 to indirectly act on the left end of the valve core 11. When there is no input current to the electromagnet 13 on the right side of the control variable mechanism, the armature will not output force to act on the right end of the valve core 11. At this time, the valve core 11 does not move, and the control high-pressure oil enters the large control variable cavity of the plunger pump through the two channels of the valve sleeve 10, and the plunger pump displacement is minimum.

[0036] When the ball head of the fork 16 rotates around the fixed pin 15, it will compress or release the control spring 8, and the force F2 formed on the support rod 7. When the electromagnet 13 on the right side of the control variable mechanism inputs current, the armature will output force F3 to act on the right end of the valve core 11. Therefore, for the valve core 11, the left side is subject to the spring force F1 set by the adjusting screw 2, the right side is subject to the electromagnetic valve force F3, and when the ball head of the fork 16 rotates around the fixed pin 15, it compresses or releases the control spring 8, and the force F2 formed on the support rod, so the balance relationship of the valve core 11 is F1 = F2 + F3. It can be seen that when the electromagnet 13 is given a certain fixed current, it generates a leftward force F3 on the valve core 11, and the adjusting screw 2 compresses the spring 6 to generate a rightward force F1 on the valve core 11, then the plunger pump must have a displacement, corresponding to the force F2 formed by the servo plunger 9 on the control spring 8, so that the valve core 11 remains balanced, and the plunger pump outputs at a certain fixed displacement.

[0037] The specific implementation is as follows: Figure 3 As shown, in the initial state, the displacement of the plunger pump is the smallest, and the servo plunger 9 compresses the control spring 8 to generate a leftward force F2 on the support rod 7. The clamping force set by the adjusting screw 2 is F1 (artificially set and adjusted, at this time F2 and F1 are in a reaction force relationship. In order to obtain the corresponding displacement of the plunger pump under the corresponding current signal, the current I is input to the electromagnet 13, and the force output by the armature of the electromagnet 13 is F3, which acts on the right end of the valve core 11. Then, under the action of the electromagnetic force F3, the valve core 11 overcomes F1 and moves to the left, closing the two channels on the valve sleeve 10, and the high-pressure oil cannot enter the control variable large cavity through the oil channel. Under the action of the reset spring, the swing angle of the plunger pump swash plate begins to increase. When the displacement of the plunger pump increases, the external signal feedback position 19 of the control variable mechanism receives the feedback signal from the increase in the displacement of the plunger pump. As shown Figure 2 , 4 As shown, the ball head of the fork 16 rotates around the fixed pin 15 to push the servo plunger 9 downward, the control spring 8 is released, and the left force F2 generated on the support rod 7 becomes smaller. From the balance of the valve core 11, it can be seen that F1 = F2 + F3, F1 is fixed, F2 becomes smaller, the valve core 11 will move to the right, open the two channels on the valve sleeve 10, and the high-pressure oil enters the variable plunger large cavity through the oil channel, and the displacement of the plunger pump begins to decrease again. When the displacement of the plunger pump decreases, the external signal receiving feedback position 19 of the control variable mechanism receives the feedback signal from the decrease in the displacement of the plunger pump. The ball head of the fork 16 rotates around the fixed pin 15 to pry the servo plunger 9 upward, and the control spring 8 is compressed, and the left force F2 generated on the support rod 7 becomes larger. At this time, the valve core 11 moves to the left again, closes the channel again, and the displacement of the plunger pump begins to increase again. This action is repeated over and over again. The valve core 11 moves at a high frequency in a short period of time, and the displacement change amplitude is very small. The human eye cannot recognize the displacement change, so the default is a fixed displacement output.

[0038] This control variable method achieved through spring force feedback does not require high component processing accuracy, but can achieve precise displacement control. Secondly, by setting different preload forces F1 on the adjustment screw, it is easy to achieve the same current and different displacement outputs, making it easy to achieve diversified control variable characteristics.

Claims

1. A force feedback controlled variable mechanism, characterized in that: The invention comprises a valve core (11) arranged in a valve body (14), a servo plunger (9) being arranged between the valve core (11) and the valve body (14), one end of the valve core (11) being inserted in a spring seat (5) for active connection, and the other end of the valve core (11) being matched with a valve sleeve (10), two channels being arranged on the valve sleeve (10), the valve sleeve (10) being connected with a fixed block (12) outside the valve body (14), an electromagnet (13) being arranged outside the fixed block (12), the electromagnet (13) being connected with a spring passing through the valve sleeve (10), The valve core (11) is matched with a valve core (11); a spring (6) is arranged in a spring seat (5), the spring seat (5) is exposed from the valve body (14), and the exposed part is plugged into the adjusting screw (2); a ring groove for matching with a shift fork (16) is arranged on the servo plunger (9), and the shift fork (16) is exposed from the cavity on the side of the valve body (14); a support rod (7) is passed through the valve core (11), and a control spring (8) is arranged on the outer sleeve of the valve core (11) between the support rod (7) and the servo plunger (9).

2. The force feedback controlled variable mechanism according to claim 1, characterized in that: The adjusting screw (2) and the valve core (11) are coaxially arranged.

3. The force feedback control variable mechanism according to claim 1, characterized in that: The outer end of the adjusting screw (2) is provided with a cap (1).

4. The force feedback control variable mechanism according to claim 3, characterized in that: A nut (4) for tightening and sealing the adjusting screw (2) is provided between the cap (1) and the spring seat (5).

5. The force feedback controlled variable mechanism according to claim 1, characterized in that: The spring seat (5) is covered with a nut (3) for adjusting the preload of the spring (6).

6. The force feedback control variable mechanism according to claim 1, characterized in that: A fixing pin (15) is provided in the cavity on the side of the valve body (14), and the fixing pin (15) is inserted into the shift fork (16) and serves as a fulcrum for the rotation of the shift fork (16).

7. The force feedback controlled variable mechanism according to claim 1, characterized in that: A shoulder for limiting position is provided on one side of the valve sleeve (10), and the shoulder is fixedly connected to the fixing block (12) and the valve body (14) by means of screws; the fixing block (12) is connected to the electromagnet (13) by means of threads.

8. The force feedback controlled variable mechanism according to claim 1, characterized in that: The valve core (11) and the valve sleeve (10) are nested with each other, one end of the valve core (11) contacts the armature end face of the electromagnet (13), and the other end cooperates with the support rod (7) through a hemisphere.

9. The force feedback control variable mechanism according to claim 6, characterized in that: The ball head portion of the shift fork (16) matches the annular groove of the servo plunger (9), and the fixing pin (15) is arranged in a cavity on the side of the valve body (14) and serves as a fulcrum for the rotation of the shift fork (16).

10. The force feedback controlled variable mechanism according to claim 1, characterized in that: A port of the first channel (17) on the valve sleeve (10) close to the servo plunger (9) is a P port, another port of the second channel (18) close to the fixed block (12) relative to the P port is an A port, and a U-shaped fork opening of the shift fork (16) exposed from the valve body (14) is a position (19) for receiving external signal feedback.

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