Hydraulic distributor with shut-off valve function

Abstract

The present invention discloses a hydraulic distributor with a stop valve function, comprising: a valve body, the valve body is provided with a valve stem cavity, a limit shaft cavity and a stop valve cavity, a valve stem is slidably arranged in the valve stem cavity, a limit shaft is slidably arranged in the limit shaft cavity, and a stop valve is arranged in the stop valve cavity; the limit shaft is provided with an annular groove, and a hydraulic control oil port communicating with a pressure oil port is provided at the intersection of the limit shaft cavity and the stop valve cavity; a boss is provided at the end of the valve core of the stop valve, and the boss corresponds to the position of the annular groove of the limit shaft; a valve stem groove is provided at one end of the valve stem, and the valve stem groove is provided with an outer end face and an inner end face, and the limit shaft is fixedly connected with a shift fork, and the shift fork is sleeved in the valve stem groove. When the hydraulically controlled distributor is in the ascending, descending and floating working positions, the stop valve can be automatically opened and maintained without the need for an electric control system and a linear actuator, and the structure is simple.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic suspension devices, and in particular to a hydraulic distributor with a stop valve function. Background Art

[0002] The hydraulic suspension device of agricultural equipment (such as tractors) is used to hang suspended or semi-suspended agricultural implements, lift and lower agricultural implements, adjust tillage depth, realize loading and hydraulic power output, etc. The hydraulic suspension device consists of a hydraulic system and a suspension mechanism. The hydraulic system includes an oil pump, a distributor, a lifting cylinder, an oil cylinder operating mechanism, etc. The suspension mechanism includes an upper pull rod, a lower pull rod, a lifting arm, etc. On the one hand, by manipulating the distributor, the agricultural implement can be raised, lowered, neutralized, and floated, so that the tractor has position control, force control, and force-position integrated control functions. On the other hand, in the field transfer operation, the hydraulic suspension device can realize active shock absorption of the agricultural implement.

[0003] During use, it was found that when the hydraulic distributor was in the neutral working mode, the force applied by the agricultural implement to the lifting cylinder created high pressure on the hydraulic oil, which was transmitted to the hydraulic distributor and leaked through the gap between the valve body and the valve stem in the hydraulic distributor, causing the agricultural implement to sink.

[0004] In order to solve the above technical problems, the applicant of the present invention disclosed a stop valve of a hydraulic suspension device in Chinese invention patent application CN202011001404.4, disclosed an intelligent control system of a hydraulic suspension device in Chinese invention patent application CN202011003075.7, and disclosed a hydraulic distributor of a hydraulic suspension device in Chinese invention patent application CN202011001409.7. In the above three patent applications, the stop valve is arranged between the rodless chamber of the lifting cylinder of the hydraulic suspension device and the first working oil port of the hydraulic distributor of the hydraulic suspension device. When the hydraulic distributor is in a neutral state, the stop valve is closed under the elastic force of the return spring, cutting off the connection between the rodless chamber of the lifting cylinder and the hydraulic distributor, thereby avoiding the sinking of the agricultural implements due to the leakage of the hydraulic distributor. Since the valve core of the stop valve includes a first valve core section and a second valve core section with the same outer diameter, an annular groove is arranged between the first valve core section and the second valve core section, the annular groove corresponds to the first cavity position of the first valve sleeve, the first valve core section is slidably matched with the first valve sleeve, the second valve core section is slidably matched with the second valve sleeve, the second valve core sleeve is provided with a flange near the annular groove, the flange is provided with a valve core sealing conical surface, the end of the first valve sleeve is provided with a valve sleeve sealing conical surface, the valve core sealing conical surface and the valve sleeve sealing conical surface have different tapers, and when the return spring acts When the valve core sealing cone is pressed against the inner edge of the valve sleeve sealing cone, the hydraulic oil can be filled to the inner edge of the valve sleeve sealing cone, so that the first chamber is disconnected from the second chamber. Since the outer diameters of the first valve core section and the second valve core section are the same, as well as the inner diameters of the first valve sleeve and the second valve sleeve, the force of the hydraulic oil on the valve core in the first chamber is zero, and the force of the hydraulic oil on the valve core in the second chamber is also zero. In this way, to open the valve, it is only necessary to overcome the elastic force of the return spring, which is completely unaffected by the hydraulic oil flowing through the valve, making the operation more sensitive and the use more reliable.

[0005] It is very convenient to control the stop valve with the hydraulic system of the hydraulic suspension device. In the above technical solution, the free end of the first valve sleeve is exposed as a hydraulic control port, and the hydraulic control port is connected to the main oil circuit of the hydraulic suspension device. The preset elastic force of the return spring is greater than the thrust of the oil pressure on the valve core when the main oil circuit is in a pressure relief state, but less than the thrust of the oil pressure on the valve core when the main oil circuit is in a high-pressure state. When the hydraulic distributor is in the rising working position and the falling working position, the main oil circuit of the hydraulic suspension device is in a high-pressure state. The valve core can overcome the elastic force of the return spring under the action of the high-pressure oil to open the stop valve.

[0006] However, when the hydraulic distributor is in the floating working position, the main oil circuit of the hydraulic suspension device is in an unloaded state, and its oil pressure is insufficient to overcome the elastic force of the return spring. In order to ensure that the stop valve can be opened in this state, an electronic control system must be used to control the linear actuator to apply axial force to the stop valve core. In this way, the control system of the hydraulic control valve will become more complicated. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a hydraulic distributor with a shut-off valve function. When the hydraulically controlled distributor is in the ascending, descending and floating working positions, the shut-off valve can be automatically opened and maintained without the need for an electric control system and a linear actuator, and has a simple structure.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A hydraulic distributor with a stop valve function comprises: a valve body, the valve body is provided with a valve stem cavity, a valve stem is slidably arranged in the valve stem cavity, the valve stem passes through the valve stem cavity, the valve stem cavity is provided with a first working oil cavity communicated with a first working oil port, a second working oil cavity communicated with a second working oil port, a pressure oil cavity communicated with a pressure oil port and a return oil cavity communicated with an oil return port, a sealing end cover is provided on one side of the valve body; one end of the valve stem is connected to a hydraulic push rod, and a valve stem return spring is provided between the other end and the sealing end cover; under the joint action of the hydraulic push rod and the valve stem return spring, when the valve stem is located at different axial positions, the hydraulic distributor is respectively in an ascending working position, a neutral working position, a descending working position and a floating working position; when the valve stem moves from left to right, the hydraulic distributor is sequentially in an ascending working position, a neutral working position, a descending working position and a floating working position.

[0010] The valve body is provided with a limit shaft cavity and a stop valve cavity, the limit shaft cavity is arranged in parallel with the valve stem cavity, and the limit shaft cavity is vertically connected with the stop valve cavity; a limit shaft is slidably arranged in the limit shaft cavity, one end of the limit shaft is pressed against a limit shaft return spring arranged in the limit shaft cavity, under the action of the limit shaft return spring, the other end of the limit shaft is pressed against the sealing end cover, the elastic force of the limit shaft return spring is smaller than the elastic force of the valve stem return spring, the limit shaft is provided with an annular groove, and a hydraulic control oil port connected with the pressure oil port is provided at the intersection of the limit shaft cavity and the stop valve cavity; a stop valve is arranged in the stop valve cavity, the stop valve comprises a valve sleeve, a valve core, a valve core return spring and a sealing cover, the valve The core return spring force is greater than the axial thrust of the hydraulic oil on the valve core in the neutral working position. The stop valve cavity is provided with a first oil groove and a second oil groove. The valve sleeve is provided with a first oil port and a second oil port. The first oil port is communicated with the first oil groove, and the second oil port is communicated with the second oil groove. The sealing gland is threadedly connected to the open end of the stop valve cavity to squeeze and fix the valve sleeve in the stop valve cavity. The valve core return spring is located in the valve sleeve and axially clamped between the sealing gland and the valve core. A boss is provided at the end of the valve core, and the boss corresponds to the position of the annular groove of the limit shaft; the end of the valve stem located on one side of the valve stem return spring is provided with a valve stem groove, and the valve stem groove is provided with an outer The side end surface and the inner end surface, the limit shaft is fixedly connected with a shift fork, and the shift fork is sleeved in the valve stem groove; when the hydraulic distributor is in the neutral working position and one end of the limit shaft is against the sealing end cover, the distance from the outer end surface of the shift fork to the outer end surface of the valve stem groove is greater than or equal to the distance that the valve stem moves from the neutral working position to the descending working position, but less than the distance that the valve stem moves from the neutral working position to the floating working position, the distance from the inner end surface of the shift fork to the inner end surface of the valve stem groove is greater than or equal to the distance that the valve stem moves from the neutral working position to the ascending working position, and the distance from the inner end surface of the shift fork to the end surface of the valve body is greater than or equal to the distance that the valve stem moves from the neutral working position to the ascending working position. Move to the distance of the floating working position; when the pressure oil port is in a unloading state and the boss position is opposite to the annular groove, the boss falls into the annular groove, and under the action of the valve core return spring, the first oil port is disconnected from the second oil port, and the stop valve is closed; when the pressure oil port is in a high-pressure state, the valve core is lifted up, the boss is disengaged from the annular groove, the first oil port is connected with the second oil port, and the stop valve is opened; when the pressure oil port is in a unloading state and the limit shaft causes the annular groove and the boss to be offset under the action of the shift fork, the limit shaft limits the boss from falling into the annular groove, the first oil port is connected with the second oil port, and the stop valve is opened.

[0011] In which, the valve sleeve includes a first valve sleeve and a second valve sleeve, and the valve core return spring is located in the second valve sleeve; the first valve sleeve is provided with a first cavity connected to the first oil port, and the second valve sleeve is provided with a second cavity connected to the second oil port; the valve core includes a first valve core section and a second valve core section with the same outer diameter, a valve core annular groove is provided between the first valve core section and the second valve core section, the valve core annular groove corresponds to the position of the first cavity, the first valve core section is slidably matched with the first valve sleeve, and the second valve core section is slidably matched with the second valve sleeve, the second valve core section is provided with a flange near the valve core annular groove, the flange is provided with a valve core sealing cone surface, the end of the first valve sleeve is provided with a valve sleeve sealing cone surface, the valve core sealing cone surface and the valve sleeve sealing cone surface have different tapers, and under the action of the valve core return spring, the valve core sealing cone surface presses against the inner edge of the valve sleeve sealing cone surface to disconnect the first cavity from the second cavity.

[0012] Wherein, the first oil groove is communicated with the first working oil port of the hydraulic distributor, and the second oil groove is communicated with the rodless chamber of the lifting cylinder of the hydraulic suspension device. Or

[0013] The communication relationship between the first oil groove and the second oil groove is reversed, that is, the first oil groove is communicated with the rodless chamber of the lifting cylinder, and the second oil groove is communicated with the first working oil port of the hydraulic distributor.

[0014] Wherein, the valve stem is a hollow valve stem, and the valve stem return spring is arranged in the hollow cavity of the hollow valve stem.

[0015] After adopting the above technical solution, the technical effects achieved by the present invention are:

[0016] 1. When the hydraulic distributor is in the neutral working position, the pressure oil port is in the unloading state and the boss position is opposite to the annular groove. Under the action of the valve core return spring, the boss falls into the annular groove, the first oil port is disconnected from the second oil port, and the stop valve is closed; when the hydraulic distributor is in the rising working position or the falling working position, the pressure oil port is in the high-pressure state, the limit shaft is located in the neutral working position of the valve stem and does not move, the valve core is lifted up, the boss is separated from the annular groove, the first oil port is connected with the second oil port, and the stop valve is opened; in the process of the valve stem moving from the falling working position to the floating working position, under the premise that the valve core is lifted up, the valve stem drives the shift fork to move the limit shaft to the right (in the direction shown in the figure) to reach the floating working position. When the hydraulic control distributor is in the neutral working position, the pressure oil port is in the unloading state. At this time, the positions of the annular groove and the boss are staggered, the limit shaft limits the boss from falling into the annular groove, the first oil port is connected with the second oil port, and the stop valve is opened; when the floating state is ended and it is necessary to return to the neutral / upward / downward working position, the electric control system first controls the valve stem to move left through the hydraulic push rod. At this time, since the limit shaft reset spring may not be sufficient to overcome the friction between the stop valve spool and the limit shaft, the limit shaft does not move, and continues to control the valve stem to move left (in the direction shown in the figure) to the downward working position. The pressure oil port is in a high pressure state, pushing the stop valve spool to move upward and disengage from the annular groove of the limit shaft. The limit shaft will move left to the neutral working position under the action of the limit shaft reset spring. As can be seen from the above, when the hydraulic control distributor is in the neutral working position, the stop valve will automatically close. When the hydraulic control distributor is in the upward, downward and floating working positions, the stop valve can be automatically opened and maintained without the need for an electric control system and a linear actuator, and the structure is simple.

[0017] 2. In the neutral state of the present invention, the stop valve is closed under the elastic force of the valve core return spring, cutting off the connection between the rodless chamber of the lifting cylinder and the hydraulic distributor, thereby avoiding the sinking of the farm implement due to leakage of the hydraulic distributor. Since the valve core of the stop valve of the present invention includes a first valve core section and a second valve core section with the same outer diameter, an annular groove is provided between the first valve core section and the second valve core section, and the annular groove corresponds to the first chamber position of the first valve sleeve, the first valve core section is slidably matched with the first valve sleeve, and the second valve core section is slidably matched with the second valve sleeve, and the second valve core sleeve is provided with a flange near the annular groove, and the flange is provided with a valve core sealing cone surface, and a valve sleeve sealing cone surface is provided at the end of the first valve sleeve, and the taper of the valve core sealing cone surface is different from that of the valve sleeve sealing cone surface, and the return spring Under the action, when the valve core sealing cone surface presses against the inner edge of the valve sleeve sealing cone surface, the hydraulic oil can be filled to the inner edge of the valve sleeve sealing cone surface, so that the first chamber is disconnected from the second chamber. Since the outer diameters of the first valve core section and the second valve core section are the same, and the inner diameters of the first valve sleeve and the second valve sleeve are also the same, the force of the hydraulic oil on the valve core in the first chamber is zero, and the force of the hydraulic oil on the valve core in the second chamber is also zero. In this way, to open the valve, it is only necessary to overcome the elastic force of the return spring, and it is not affected by the hydraulic oil flowing through the valve. The operation is more sensitive and the use is more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view of a hydraulic distributor with a stop valve function according to an embodiment of the present invention, in which the valve stem and the limit axis are located in the same cross section;

[0019] Figure 2 yes Figure 1 A front view of the shift fork in the illustrated embodiment;

[0020] Figure 3 yes Figure 1 A longitudinal sectional view of the limiting shaft in the illustrated embodiment;

[0021] Figure 4 yes Figure 1 A cross-sectional view of the working state structure in which the stop valve and the limit axis are located in the same section when the hydraulic distributor is in the neutral working position in the illustrated embodiment;

[0022] Figure 5 yes Figure 4 A longitudinal sectional view of the stop valve;

[0023] Figure 6 yes Figure 5 A partial enlarged view of point Ⅰ in the middle;

[0024] Figure 7 yes Figure 5 A longitudinal sectional view of the middle valve core;

[0025] Figure 8 yes Figure 1 A cross-sectional view of the working state structure in which the stop valve and the limit axis are located in the same cross section when the hydraulic distributor is in the descending working position or the ascending working position in the illustrated embodiment;

[0026] Fig. 9 yes Figure 1 A cross-sectional view of the working state structure in which the stop valve and the limit axis are located in the same section when the hydraulic distributor is in the floating working position in the illustrated embodiment;

[0027] In the figure:

[0028] 100-valve body, 101-valve stem, 102-valve stem groove, 103-valve stem return spring, 104-sealing end cover, 105-first oil groove, 106-second oil groove, 107-hydraulic control oil port, 108-hydraulic push rod;

[0029] 200-limiting shaft, 201-annular groove, 202-limiting shaft return spring, 203-shift fork;

[0030] 301-first valve sleeve, 3011-sleeve sealing cone, 301a-first cavity, 301A-first oil port, 302-second valve sleeve, 302b-second cavity, 302B-second oil port, 303-sealing gland, 304-return spring, 305-valve core, 3051-first valve core section, 3052-second valve core section, 3053-flange, 3053A-sleeve sealing cone, 3054-sleeve annular groove, 3055-boss, d-outer diameter, α-angle difference between the valve core sealing cone and the valve core sealing cone;

[0031] a-first working oil chamber, b-second working oil chamber, p-pressure oil chamber, t-return oil chamber;

[0032] S1-the distance from the outer end face of the fork to the outer end face of the valve stem groove, S2-the distance from the inner end face of the fork to the inner end face of the valve stem groove, S3-the distance from the inner end face of the fork to the end face of the valve body. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0034] like Figures 1 to 3As shown, a hydraulic distributor with a stop valve function, a valve body 100 is provided with a valve stem cavity, a valve stem 101 is slidably arranged in the valve stem cavity, the valve stem 101 penetrates the valve stem cavity, the hydraulic distributor is provided with a first working oil port, a second working oil port, a pressure oil port and an oil return port, the valve stem cavity is provided with a first working oil chamber a communicating with the first working oil port, a second working oil chamber b communicating with the second working oil port, a pressure oil chamber p communicating with the pressure oil port and an oil return chamber t communicating with the oil return port. A sealing end cap 104 is provided on one side of the valve body 100, a hydraulic push rod 108 is connected to one end of the valve stem 101, and a valve stem return spring 103 is provided between the other end and the sealing end cap 104. Preferably, the valve stem 101 is a hollow valve stem, and the valve stem return spring 103 is provided in the hollow cavity of the hollow valve stem. Under the joint action of the hydraulic push rod 108 and the valve stem return spring 103, when the valve stem 101 is located at different axial positions, the hydraulic distributor is in different working positions respectively; in this embodiment, when the valve stem 101 moves from left to right, the hydraulic distributor is in the ascending working position, the neutral working position, the descending working position and the floating working position respectively.

[0035] like Figures 4 to 7 As shown, the valve body 100 is provided with a limit shaft cavity and a stop valve cavity, the limit shaft cavity is arranged in parallel with the valve stem cavity, and the limit shaft cavity is vertically connected with the stop valve cavity.

[0036] A limit shaft 200 is slidably arranged in the limit shaft cavity, and one end of the limit shaft 200 is pressed against a limit shaft return spring 200 arranged in the limit shaft cavity. Under the action of the limit shaft return spring 200, the other end of the limit shaft 200 presses against the sealing end cover 104. The elastic force of the limit shaft return spring is smaller than the elastic force of the valve stem return spring. The limit shaft 200 is provided with an annular groove 201. A hydraulic control oil port 107 communicated with the pressure oil port is provided at the intersection of the limit shaft cavity and the stop valve cavity. The hydraulic oil introduced from the pressure oil port acts on the bottom of the valve core 305.

[0037] A stop valve is arranged in the stop valve cavity, and the stop valve includes a valve sleeve, a valve core 305, a valve core return spring 304 and a sealing cover 303. The elastic force of the valve core return spring is greater than the axial thrust of the hydraulic oil on the valve core 305 in the neutral working position. The stop valve cavity is provided with a first oil groove 105 and a second oil groove 106. The valve sleeve is provided with a first oil port 301A and a second oil port 302B. The first oil port 301A is communicated with the first oil groove 105, and the second oil port is communicated with the second oil groove 106. The sealing cover 303 is threadedly connected to the open end of the stop valve cavity to squeeze and fix the valve sleeve in the stop valve cavity. The valve core return spring 304 is located in the valve sleeve and axially clamped between the sealing cover 303 and the valve core 305. A boss 3055 is arranged at the end of the valve core 305, and the boss 3055 corresponds to the position of the annular groove 201 of the limiting shaft.

[0038] Figures 5 to 7 The detailed structure of the stop valve is shown. The valve sleeve includes a first valve sleeve 301 and a second valve sleeve 302. The first valve sleeve 301 and the second valve sleeve 302 can be axially arranged and squeezed and fixed in the stop valve cavity by screwing the sealing gland 303. The valve core return spring 304 is located in the second valve sleeve 302; the first valve sleeve 301 is provided with a first cavity 301a connected to the first oil port 301A, and the second valve sleeve 302 is provided with a second cavity 302b connected to the second oil port 302B.

[0039] The valve core 305 includes a first valve core section 3051 and a second valve core section 3052 with the same outer diameter. A valve core annular groove 3054 is provided between the first valve core section 3051 and the second valve core section 3052. The valve core annular groove 3054 corresponds to the position of the first cavity 301a. The first valve core section 3051 is slidably matched with the first valve sleeve 301, and the second valve core section 3052 is slidably matched with the second valve sleeve 302. The second valve core section 3052 is close to the valve core annular groove 301a. A flange 3053 is provided at 54, and a valve core sealing cone surface 3053A is provided on the flange 3053. A valve sleeve sealing cone surface 3011 is provided at the end of the first valve sleeve 301. The taper of the valve core sealing cone surface 3053A is different from that of the valve sleeve sealing cone surface and has an angle difference α. Under the action of the valve core return spring 304, the valve core sealing cone surface 3053A presses against the inner edge of the valve sleeve sealing cone surface 3011 to disconnect the first cavity 301a from the second cavity 302b.

[0040] In the present invention, the taper of the valve core sealing cone 3053A is different from that of the valve sleeve sealing cone 3011. Under the action of the valve core return spring 304, when the valve core sealing cone 3053A abuts against the inner edge of the valve sleeve sealing cone 3011, the hydraulic oil can fill the inner edge of the valve sleeve sealing cone 3011, so that the first cavity 301a is disconnected from the second cavity 302b. Since the outer diameters d of the first valve core section 3051 and the second valve core section 3052 are the same, the first valve core section 3051 and the first valve sleeve 301 are slidably matched, and the second valve core section 3052 is 3052 interacts with the second valve sleeve 302, so the outer diameter d of the first valve core section 3051 is the same as the inner diameter of the first valve sleeve 301, and the outer diameter d of the second valve core section 3052 is also the same as the inner diameter of the second valve sleeve 302. Therefore, in the first chamber 301a, the force of the hydraulic oil on the valve core 305 is zero, and in the second chamber 302b, the force of the hydraulic oil on the valve core 305 is also zero. In this way, to open the valve, it is only necessary to overcome the elastic force of the valve core return spring, and it is not affected by the hydraulic oil flowing through this valve. The operation is more sensitive and the use is more reliable.

[0041] like Figure 1 As shown, a valve stem groove 102 is provided at the end of the valve stem 101 on the side of the valve stem return spring 103, and the valve stem groove 102 is provided with an outer end face and an inner end face (the right side is the outer side, and the left side is the inner side). The limit shaft 200 is fixedly connected with a shift fork 203, and the shift fork 203 is sleeved in the valve stem groove 102. When the valve stem 101 moves axially, the inner / outer end faces of the valve stem groove 102 will drive the limit shaft 200 to move through the shift fork 203.

[0042] like Figure 1 As shown, when the hydraulic distributor is in the neutral working position and one end of the limit shaft 200 is against the sealing end cover 104, the distance S1 from the outer end surface of the fork 203 to the outer end surface of the valve stem groove 102 is greater than or equal to the distance that the valve stem 101 moves from the neutral working position to the descending working position but less than the distance that the valve stem 101 moves from the neutral working position to the floating working position, so that when the valve stem 101 moves from the neutral working position to the descending working position, the limit shaft 200 does not move. The distance S2 from the inner end surface of the fork 203 to the inner end surface of the valve stem groove 102 is greater than or equal to the distance that the valve stem 101 moves from the neutral working position to the ascending working position, so that when the valve stem 101 moves to the left from the neutral working position to the ascending working position, the limit shaft 200 does not move. The distance S3 from the inner end face of the shift fork 203 to the end face of the valve body 100 is greater than or equal to the distance that the valve stem 101 moves from the neutral working position to the floating working position. Thus, when the valve stem 101 moves rightward from the neutral working position to the floating working position, the shift fork will not interfere with the valve body 100.

[0043] like Figure 4As shown, when the hydraulic distributor is in the neutral working position, the pressure oil port is in a unloading state and the boss 3055 is located opposite the annular groove 210. Under the action of the valve core return spring 304, the boss 3055 falls into the annular groove 201, the first oil port 301A is disconnected from the second oil port 302B, and the stop valve is closed.

[0044] like Figure 8 As shown, when the hydraulic distributor is in the ascending working position or the descending working position, the pressure oil port is in a high-pressure state, the limit shaft 200 is located in the neutral working position and does not move, the valve core 305 is lifted up, the boss 3055 is disengaged from the annular groove 201, the first oil port 301A is connected to the second oil port 302B, and the stop valve is opened.

[0045] like Figure 1 and Fig. 9 As shown, in the process of the valve stem 101 moving from the descending working position to the floating working position, under the premise that the valve core 305 is lifted up, the valve stem 101 drives the fork 203 to move the limit shaft 200 to the right (the direction shown in the figure). When reaching the floating working position, the pressure oil port is in an unloading state. At this time, the positions of the annular groove 201 and the boss 3055 are staggered, the limit shaft 200 restricts the boss 3055 from falling into the annular groove 201, the first oil port 301A is connected to the second oil port 302B, and the stop valve is opened.

[0046] When the floating state ends and it is necessary to return to the neutral / upward / downward working position, the electronic control system first controls the valve stem 101 to move left through the hydraulic push rod 108. At this time, since the limit shaft return spring 202 may not be sufficient to overcome the friction between the stop valve spool 305 and the limit shaft 200, the limit shaft 200 does not move. When the valve stem 101 continues to be controlled to move left (in the direction shown in the figure) to the downward working position, the pressure oil port is in a high-pressure state, pushing the stop valve spool 305 to move upward and disengage from the limit shaft 200. The limit shaft 200 will move left to the neutral working position (i.e. Figure 4 or Figure 8 As shown above, when the hydraulically controlled distributor is in the neutral working position, the stop valve will automatically close, and when the hydraulically controlled distributor is in the ascending, descending and floating working positions, the stop valve can automatically open and maintain without the need for an electric control system and a linear actuator, and the structure is simple.

[0047] When the hydraulic distributor disclosed in the present invention is applied to a hydraulic suspension device of agricultural equipment such as a tractor, the first oil groove 105 of the cut-off valve cavity is connected to the first working oil port of the hydraulic distributor, and the second oil groove 106 is connected to the rodless cavity of the lifting cylinder of the hydraulic suspension device. Alternatively, the connection relationship between the first oil groove 105 and the second oil groove 106 is reversed, that is, the first oil groove 105 is connected to the rodless cavity of the lifting cylinder, and the second oil groove 106 is connected to the first working oil port of the hydraulic distributor.

[0048] The hydraulic distributor disclosed by the present invention, when the valve stem 101 moves from left to right, the working positions it can provide are not limited to the rising working position, the neutral working position, the descending working position and the floating working position. In order to adapt to the active shock absorption of the attached agricultural equipment during the transfer operation, the shock absorption system can also be set to a shock absorption working position. In the floating state, the neutral state but the agricultural implement is on the ground for a long time, the shutdown state, etc., the accumulator cannot be charged, which may cause the pressure in the accumulator to be very low or even zero. At this time, the electronic control unit can only control the valve stem to move to the right as shown in the attached figure, but cannot control the valve stem to move to the left. In order to achieve the purpose of manipulating the bidirectional movement of the valve stem of the hydraulic distributor under these special working conditions, a neutral charging working position and a floating charging working position can also be set. Generally speaking, the neutral working position and the shock absorption working position have the problem of oil leakage, and the stop valve needs to be closed. When in other working positions, the stop valve can be kept open. According to the principle introduced above, this can be achieved by setting the relative position of each working position and the specific displacement of the valve stem 101. It will not be repeated here.

[0049] The present invention is not limited to the above embodiments, and all improvements based on the concept, principle, structure and method of the present invention will fall within the protection scope of the present invention.

Claims

1. A hydraulic distributor with a shut-off valve function, comprising: A valve body, wherein the valve body is provided with a valve stem cavity, a valve stem is slidably arranged in the valve stem cavity, the valve stem passes through the valve stem cavity, the valve stem cavity is provided with a first working oil cavity (a) communicating with a first working oil port, a second working oil cavity (b) communicating with a second working oil port, a pressure oil cavity (p) communicating with a pressure oil port, and a return oil cavity (t) communicating with an oil return port, and a sealing end cover is arranged on one side of the valve body; one end of the valve stem is connected to a hydraulic push rod, and a valve stem return spring is arranged between the other end and the sealing end cover; under the joint action of the hydraulic push rod and the valve stem return spring, when the valve stem is located at different axial positions, the hydraulic distributor is respectively in an ascending working position, a neutral working position, a descending working position and a floating working position; when the valve stem moves from left to right, the hydraulic distributor is sequentially in the ascending working position, the neutral working position, the descending working position and the floating working position; characterized in that, The valve body is provided with a limit shaft cavity and a stop valve cavity, the limit shaft cavity is arranged in parallel with the valve stem cavity, and the limit shaft cavity is vertically connected with the stop valve cavity; A limiting shaft is slidably arranged in the limiting shaft cavity, one end of the limiting shaft presses against a limiting shaft return spring arranged in the limiting shaft cavity, under the action of the limiting shaft return spring, the other end of the limiting shaft presses against the sealing end cover, the elastic force of the limiting shaft return spring is smaller than the elastic force of the valve stem return spring, the limiting shaft is provided with an annular groove, and a hydraulic control oil port communicating with the pressure oil port is provided at the intersection of the limiting shaft cavity and the stop valve cavity; A stop valve is arranged in the stop valve cavity, and the stop valve comprises a valve sleeve, a valve core, a valve core return spring and a sealing gland. The elastic force of the valve core return spring is greater than the axial thrust of the hydraulic oil on the valve core in the neutral working position. The stop valve cavity is provided with a first oil groove and a second oil groove. The valve sleeve is provided with a first oil port and a second oil port. The first oil port is communicated with the first oil groove, and the second oil port is communicated with the second oil groove. The sealing gland is threadedly connected to the open end of the stop valve cavity to squeeze and fix the valve sleeve in the stop valve cavity. The valve core return spring is located in the valve sleeve and axially clamped between the sealing gland and the valve core. A boss is arranged at the end of the valve core, and the boss corresponds to the position of the annular groove of the limit shaft. The end of the valve stem located on one side of the valve stem return spring is provided with a valve stem groove, and the valve stem groove is provided with an outer end face and an inner end face, and the limit shaft is fixedly connected with a shift fork, and the shift fork is sleeved in the valve stem groove; when the hydraulic distributor is in the neutral working position and one end of the limit shaft is against the sealing end cover, the distance (S1) from the outer end face of the shift fork to the outer end face of the valve stem groove is greater than or equal to the distance the valve stem moves from the neutral working position to the descending working position, but less than the distance the valve stem moves from the neutral working position to the floating working position, the distance (S2) from the inner end face of the shift fork to the inner end face of the valve stem groove is greater than or equal to the distance the valve stem moves from the neutral working position to the ascending working position, and the distance (S3) from the inner end face of the shift fork to the end face of the valve body is greater than or equal to the distance the valve stem moves from the neutral working position to the floating working position; When the pressure oil port is in a unloading state and the boss is positioned opposite to the annular groove, the boss falls into the annular groove, and under the action of the valve core return spring, the first oil port is disconnected from the second oil port to close the stop valve; when the pressure oil port is in a high-pressure state, the valve core is lifted up, the boss is disengaged from the annular groove, the first oil port is connected to the second oil port, and the stop valve is opened; when the pressure oil port is in a unloading state and the limit shaft causes the annular groove and the boss to be misaligned under the action of the shift fork, the limit shaft restricts the boss from falling into the annular groove, the first oil port is connected to the second oil port, and the stop valve is opened; The valve sleeve comprises a first valve sleeve and a second valve sleeve, the valve core return spring is located in the second valve sleeve; the first valve sleeve is provided with a first cavity communicating with the first oil port, and the second valve sleeve is provided with a second cavity communicating with the second oil port; The valve core comprises a first valve core section and a second valve core section with the same outer diameter, a valve core annular groove is provided between the first valve core section and the second valve core section, the valve core annular groove corresponds to the position of the first cavity, the first valve core section is slidably matched with the first valve sleeve, the second valve core section is slidably matched with the second valve sleeve, the second valve core section is provided with a flange near the valve core annular groove, the flange is provided with a valve core sealing cone surface, the end of the first valve sleeve is provided with a valve sleeve sealing cone surface, the valve core sealing cone surface and the valve sleeve sealing cone surface have different tapers, and under the action of the valve core return spring, the valve core sealing cone surface abuts against the inner edge of the valve sleeve sealing cone surface to disconnect the first cavity from the second cavity; The valve stem is a hollow valve stem, and the valve stem return spring is arranged in the hollow cavity of the hollow valve stem.

2. The hydraulic distributor with shut-off valve function according to claim 1, characterized in that: The first oil groove is communicated with the first working oil port of the hydraulic distributor, and the second oil groove is communicated with the rodless chamber of the lifting cylinder of the hydraulic suspension device.

3. The hydraulic distributor with a shut-off valve function according to claim 2, characterized in that: The communication relationship between the first oil groove and the second oil groove is reversed, that is, the first oil groove is communicated with the rodless chamber of the lifting cylinder, and the second oil groove is communicated with the first working oil port of the hydraulic distributor.

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