Load sensitive valve of directional drilling machine

Abstract

A directional drilling machine load sensitive valve comprises a drilling valve and a working condition control valve, the drilling valve comprises a first three-position five-way valve, a second three-position five-way valve, a first pressure compensation valve, a second pressure compensation valve and a hydraulic control one-way valve which are arranged in a drilling valve body, and an oil inlet P, an oil return port T, a feedback port, a working port and a control port are formed in the drilling valve body. The oil inlet P and the oil return port T are communicated with the working ports A1 and B1 through a first three-position five-way valve and a first pressure compensation valve; the oil inlet P and the oil return port T are communicated with the working ports A2 and B2 through a second three-position five-way valve and a second pressure compensation valve; control oil cavities of the first pressure compensation valve and the second pressure compensation valve are correspondingly communicated with the feedback ports respectively; the working condition control valve comprises a first three-position four-way valve, a first two-position three-way valve, a first three-position six-way valve, a second three-position six-way valve and a third three-position five-way valve which are arranged in a control valve body. The valve is compact in structure, the valve body can be operated according to requirements, rapid adjustment can be achieved, response is sensitive, and running is stable.

Description

Technical Field

[0001] The utility model belongs to a hydraulic valve, in particular to a load sensitive valve for a directional drilling rig. Background Art

[0002] Directional drilling rigs are a type of pipeline construction tool used in the engineering industry. They are generally used in the construction of oil, natural gas and some municipal pipelines. Large directional drilling rigs are used to perform positioning drilling, hole expansion, hole cleaning, pipeline backhauling and other processes before pipeline construction. During operation, the operator needs to remotely operate the machine outside the directional drilling rig, so it is very important to ensure that the directional drilling rig operates stably and sensitively.

[0003] When a directional drill is drilling, the valve body needs to be adjusted according to the working conditions and the valve body is required to respond quickly. The existing load-sensitive valves for directional drills have the following problems:

[0004] 1. Drilling and braking cannot be fully linked, and there are many working steps, which can easily lead to human operating errors;

[0005] 2. The operating valve group has complex logic and large size, which makes it difficult to find problems and requires high skills of workers;

[0006] 3. The control valve group requires a large space for installation and has many external pipes, which makes it inconvenient to repair and replace. Utility Model Content

[0007] The technical problem to be solved by the utility model is to provide a load-sensitive valve for directional drilling rigs with a compact structure, capable of operating the valve body according to requirements and realizing rapid adjustment, and having sensitive response and stable operation.

[0008] In order to solve the above problems, the utility model adopts the following technical solutions:

[0009] A load-sensitive valve for a directional drilling rig, comprising a drilling valve and a working condition control valve, wherein the drilling valve comprises a drilling valve body and a first, third, five-way valve, a second, third, five-way valve, a first pressure compensating valve, a second pressure compensating valve, and a hydraulically controlled one-way valve arranged in the drilling valve body; an oil inlet P, an oil return port T, feedback ports LS1, LS2, working ports A1, B1, A2, B2, and control ports K1, K2 are arranged on the drilling valve body; the oil inlet P and the oil return port T are connected to the working ports A1, B1 through the first, third, five-way valve and the first pressure compensating valve connected in sequence, so as to control the rotation of the rotary motor of the power head; the oil inlet P and the oil return port T are connected to the working ports A2, B2 through the second, third, five-way valve and the second pressure compensating valve connected in sequence, so as to control the extension and retraction of the feed oil cylinder; the control oil chambers at both ends of the first pressure compensating valve and the second pressure compensating valve are connected to the feedback ports LS1, LS2 respectively;

[0010] The C port of the first three-position five-way valve is connected to the feedback port LS2 through the third one-way valve, the hydraulic one-way valve is connected between the second pressure compensation valve and the working port B2, and the control end of the hydraulic one-way valve is connected to the B port of the first three-position five-way valve, so as to realize the retreat of the feed cylinder when the rotary motor is reversed; the control ports K1 and K2 are respectively connected to the B port and the A port of the second three-position five-way valve, so as to realize the linkage of the working condition control valve when the feed cylinder is extended and retracted;

[0011] The working condition control valve includes a control valve body and a first three-position four-way valve, a first two-position three-way valve, a first three-position six-way valve, a second three-position six-way valve and a third three-position five-way valve arranged in the control valve body. An oil inlet P2, an oil return port T2, a feedback port LS2', a linkage port A1', working ports A3, A4, B4, A5 and two control ports K1', K2' are arranged on the control valve body. The oil inlet P2 and the oil return port T2 are connected with the working ports A3, A4, B4 and the control oil chamber at one end of the first two-position three-way valve through the first three-position six-way valve. The linkage port A1' and the feedback port LS2' are connected with the P port and the T port of the first three-position four-way valve respectively, and are connected with the working port A1 and the feedback port LS2 respectively through oil pipes. The A port of the first two-position four-way valve is connected with the P port of the first two-position three-way valve and the control oil chamber at the other end, the B port of the first three-position four-way valve is connected with the T port of the first two-position three-way valve and the oil return port T2, the control oil chamber at one end of the first three-position six-way valve is connected with the A port of the first two-position three-way valve and the P' port of the second three-position six-way valve respectively, the control oil chamber at the other end of the first three-position six-way valve is connected with the T port of the second three-position six-way valve, the P port of the second three-position six-way valve is connected with the oil inlet P2, the second three-position six-way valve is connected with the A, B and C ports of the third three-position five-way valve correspondingly, and the B port is connected with the oil return port T2, and the P port and T port of the third three-position five-way valve are connected with the control ports K1 and K2 correspondingly through the control ports K1' and K2' using oil pipes.

[0012] As a further preference, the drilling valve body comprises an oil inlet valve plate, a rotary valve plate, a pressure reducing relief valve plate, a one-way relief valve plate, a feed valve plate and a tail plate which are connected in sequence; the oil inlet port P and the oil return port T on the drilling valve body are arranged on the oil inlet valve plate; the first three-position five-way valve, the first pressure compensating valve and the working ports A1 and B1 are arranged on the rotary valve plate; the hydraulically controlled one-way valve and the working port B2 are arranged on the one-way relief valve plate; the second three-position five-way valve, the second pressure compensating valve and the working port A2 are arranged on the feed valve plate, and the control ports K1 and K2 are arranged on the tail plate.

[0013] As a further preference, a throttle valve, a pressure reducing valve and a first check valve which are connected in sequence are provided between the B port of the first three-position five-way valve and the control end of the hydraulically controlled check valve, and the throttle valve, the pressure reducing valve and the first check valve are arranged on the pressure reducing overflow valve plate.

[0014] As a further preference, control ports a1 and b1 are respectively provided on the valve covers at both ends of the rotary valve plate, and the control oil chambers at both ends of the first three-position five-way valve are respectively connected to the control ports a1 and b1, for an external pilot valve to control the switching of the first three-position five-way valve.

[0015] As a further preference, control ports a2 and b2 are respectively provided on the valve covers at both ends of the feed valve plate, and the control oil chambers at both ends of the second three-position five-way valve are respectively connected to the control ports a2 and b2, for an external pilot valve to control the switching of the second three-position five-way valve.

[0016] As a further preference, a second three-position four-way valve, a second two-position three-way valve and a two-position four-way valve are further provided in the control valve body of the working condition control valve, the P port and the T port of the second three-position four-way valve are respectively connected to the oil inlet P2 and the oil return port T2, the A port and the B port of the second three-position four-way valve are respectively connected to the two ends of a shuttle valve through a first pressure reducing valve, and the third port of the shuttle valve is connected to the working port A5, so as to control the operation of the brake;

[0017] The P port of the second two-position three-way valve is connected to the feedback port LS4 provided on the control valve body, the A port is connected to the T port of the two-position four-way valve, and the B port is connected to the T port of the two-position four-way valve through the second pressure reducing valve and the fourth one-way valve;

[0018] The P port of the two-position four-way valve is connected to the oil inlet P2, the A port is connected to the oil outlet P3 provided on the control valve body, and the B port is connected to the feedback port LS provided on the control valve body; it is used to select the working condition control valve or the external stable valve group to work and feedback the oil pressure to the oil pump.

[0019] As a further preferred embodiment, the control valve body includes a working condition switching valve plate, a clamper single-acting valve plate, a control valve plate, a brake pressure reducing valve plate, an LS pressure reducing valve plate and an LS switching valve plate which are connected in sequence; the first three-position four-way valve and the first two-position three-way valve are arranged on the working condition switching valve plate, the first three-position six-way valve and the second three-position six-way valve are arranged on the clamper single-acting valve plate, the third three-position five-way valve and the two control ports K1', K2' are arranged on the control valve plate, the second three-position four-way valve, the first pressure reducing valve and the corresponding shuttle valve are arranged on the brake pressure reducing valve plate, the second two-position three-way valve, the second pressure reducing valve and the fourth one-way valve are arranged on the LS pressure reducing valve plate, and the two-position four-way valve, the oil inlet P2 and the feedback port LS are arranged on the LS switching valve plate.

[0020] As a further preferred embodiment, a travel control valve is further provided, the travel control valve comprising a travel valve body, on which a third three-position six-way valve, a third pressure compensation valve, a fourth three-position six-way valve, a fourth pressure compensation valve, and an oil inlet P1, an oil return port T1, working ports A6, B6 and working ports A7, B7 are provided;

[0021] The oil inlet P1 and the oil return port T1 are connected to the working ports A6 and B6 through the third pressure compensation valve and the third three-position six-way valve connected in sequence, and are used to control the rotation of the travel motor of the crawler on one side of the directional drilling rig; the oil inlet P1 and the oil return port T1 are connected to the working ports A7 and B7 through the fourth pressure compensation valve and the fourth three-position six-way valve connected in sequence, and are used to control the rotation of the travel motor of the crawler on the other side of the directional drilling rig.

[0022] As a further preference, the travel valve body is further provided with control ports a3, b3, a4, b4, a feedback port LS3, a first shuttle valve and a second shuttle valve; the control oil chambers at both ends of the third three-position six-way valve are communicated with the control ports a3 and b3 respectively, and the control oil chambers at both ends of the fourth three-position six-way valve are communicated with the control ports a4 and b4 respectively, for an external pilot valve to control the two three-position six-way valves; an inlet at one end of the first shuttle valve is communicated with the control oil chamber at one end of the third pressure compensation valve and the P' port of the third three-position six-way valve, and an inlet at the other end is communicated with the outlet of the second shuttle valve, and the outlet of the first shuttle valve is communicated with the feedback port LS3, and an inlet at one end of the second shuttle valve is communicated with the control oil chamber at one end of the fourth pressure compensation valve and the P' port of the fourth three-position six-way valve;

[0023] The feedback port LS3 and the feedback port LS1 are connected to the feedback port LS4 via a third shuttle valve for feeding back the oil pressure to the oil pump.

[0024] The beneficial effects of the utility model are:

[0025] 1. The first three-position five-way valve and the first pressure compensation valve connected in sequence in the drilling valve body can control the forward or reverse rotation of the power head rotary motor, and the second three-position five-way valve and the second pressure compensation valve connected in sequence in the drilling valve body can control the extension and retraction of the feed cylinder; since the linkage port A1' and the feedback port LS2' of the working condition control valve are respectively connected to the working port A1 and the feedback port LS2 of the drilling valve through the oil pipe, the P port and the T port of the third three-position five-way valve are respectively connected to the control ports K1 and K2 through the control ports K1' and K2' using the oil pipe, therefore, by controlling the states of the first three-position four-way valve, the second three-position six-way valve and the third three-position five-way valve, the linkage control of the chuck and the clamp with the rotary motor and the feed cylinder can be realized, the operation is simple, and human operation errors can be avoided.

[0026] 2. Since the hydraulically controlled one-way valve is connected between the second pressure compensation valve and the working port B2, the control end of the hydraulically controlled one-way valve is connected to the B port of the first three-position five-way valve, and a throttle valve, a pressure reducing valve and a first one-way valve which are connected in sequence are arranged between the B port of the first three-position five-way valve and the control end of the hydraulically controlled one-way valve, when the rotary motor is reversed by controlling the first three-position five-way valve, the feed cylinder can be linked to retreat, thereby realizing the drill rod unloading operation and simplifying the valve body control structure.

[0027] 3. The second and third position six-way valve of the working condition control valve can be used to control whether the status of the drill pipe, the clamp and the chuck are linked or not. It is divided into three working states: linkage state, single-action state I (clamp clamped, chuck open) and single-action state II (chuck clamped, clamp open). The drill pipe, the clamp and the chuck are linked, and the status of the chuck and the clamp can be adjusted by controlling the drill pipe status, simplifying the operation steps; it can also be switched to the single-action state as needed, and the status of the chuck and the clamp can be changed manually to facilitate the control requirements in special circumstances.

[0028] 4. The overall structure is compact, easy to install, occupies little space, is easy to operate and maintain, is highly practical, and is suitable for most working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a hydraulic principle diagram of the utility model.

[0030] Figure 2 It is a hydraulic principle diagram of the drilling valve of the utility model.

[0031] Figure 3 It is the hydraulic principle diagram of the working condition control valve.

[0032] Figure 4 It is the hydraulic principle diagram of the travel control valve.

[0033] Figure 5 It is a structural schematic diagram of a drilling valve of the utility model.

[0034] Figure 6 yes Figure 5 Rear view of.

[0035] Figure 7 yes Figure 5 Left view of .

[0036] Figure 8 It is a structural diagram of the working condition control valve.

[0037] Fig. 9 yes Figure 8 Rear view of.

[0038] Fig.10 yes Figure 8 Left view of .

[0039] Fig.11 yes Figure 8 Right view of .

[0040] Fig.12 It is a structural schematic diagram of the travel control valve of the utility model.

[0041] Fig.13 yes Fig.12 Left view of .

[0042] Fig.14 yes Fig.12 Right view of .

[0043] Fig.15 yes Fig.12 Bottom view of .

[0044] In the figure: drilling valve 1, working condition control valve 2, travel control valve 3, third shuttle valve 4, manual two-position four-way valve 5, first pilot valve group 6, second pilot valve group 7, and stabilizing valve group 8.

[0045] A first three-position five-way valve 101, a second one-way valve 102, a first pressure compensating valve 103, a third one-way valve 104, a first relief valve 105, a second relief valve 106, a main safety valve 107, a second three-position five-way valve 108, a second pressure compensating valve 109, a hydraulically controlled one-way valve 110, a first one-way valve 111, a pressure reducing valve 112, a throttle valve 113, an oil inlet valve plate 114, a rotary valve plate 115, a pressure reducing and relief valve plate 116, a one-way relief valve plate 117, a feed valve plate 118, and a tail plate 119;

[0046] The first three-position four-way valve 201, the first two-position three-way valve 202, the first three-position six-way valve 203, the second three-position six-way valve 204, the third three-position five-way valve 205, the second two-position three-way valve 206, the second pressure reducing valve 207, the fourth one-way valve 208, the two-position four-way valve 209, the shuttle valve 210, the first pressure reducing valve 211, the second three-position four-way valve 212, the working condition switching valve plate 213, the clamper single-acting valve plate 214, the control valve plate 215, the brake pressure reducing valve plate 216, the LS pressure reducing valve plate 217, and the LS switching valve plate 218,

[0047] The third pressure compensating valve 301, the third three-position six-way valve 302, the fourth pressure compensating valve 303, the fourth three-position six-way valve 304, the first shuttle valve 305, the second shuttle valve 306, the third overflow valve 307, the third pressure reducing valve 308, the first valve plate 309, the second valve plate 310, the third valve plate 311, and the fourth valve plate 312. DETAILED DESCRIPTION

[0048] like Figure 1 to Figure 15As shown, the utility model relates to a load-sensitive valve for a directional drilling rig, including a drilling valve 1 and a working condition control valve 2. The drilling valve 1 includes a drilling valve body and a first three-position five-way valve 101, a second three-position five-way valve 108, a first pressure compensation valve 103, a second pressure compensation valve 109, and a hydraulically controlled one-way valve 110 arranged in the drilling valve body. An oil inlet P, an oil return port T, feedback ports LS1, LS2, working ports A1, B1, A2, B2, and control ports K1, K2 are arranged on the drilling valve body. The oil inlet P and the oil return port T are connected to the working ports A1 and B1 through the first three-position five-way valve 101 and the first pressure compensation valve 103 connected in sequence, and are used to control the rotation of the power head rotation motor; the oil inlet P and the oil return port T are connected to the working ports A2 and B2 through the second three-position five-way valve 108 and the second pressure compensation valve 109 connected in sequence, and are used to control the extension and retraction of the feed cylinder; the control oil chambers at both ends of the first pressure compensation valve 103 and the second pressure compensation valve 109 are connected to the feedback ports LS1 and LS2 respectively.

[0049] The first three-position five-way valve 101 and the second three-position five-way valve 108 are both hydraulically controlled valves, and their P ports are connected to the oil inlet P through an internal oil passage, and their T ports are connected to the oil return port T through an internal oil passage, respectively. The A, B, and C ports of the first three-position five-way valve 101 are connected to the T, P, and P' ports of the first pressure compensation valve 103, respectively, and the C port is connected to the feedback port LS2 through the third one-way valve 104; the A, B, and C ports of the second three-position five-way valve 108 are connected to the T, P, and P' ports of the second pressure compensation valve 109, respectively; the first pressure compensation valve 103 is a two-position six-way valve, and its A and B ports are connected to the working ports A1 and B1, respectively, and the A port is connected to the feedback port LS1 through a second one-way valve 102 and an internal control oil passage, and its C port is connected to the feedback port LS1 through an internal control oil passage.

[0050] The first pressure compensating valve 103 is initially located at the lower position. When in the lower position, its P port and B port, T port and A port are throttled and connected respectively, and P' port and C port are cut off; when in the upper position, its P port and B port, T port and A port, P' port and C port are connected respectively.

[0051] The first three-position five-way valve 101 and the second three-position five-way valve 108 are initially located in the middle position. When in the middle position, the P port is cut off, and the A, B, C ports are connected to the T port; when in the upper position, the P port is throttled and connected to the A and C ports, and the B port is connected to the T port; when in the lower position, the P port is throttled and connected to the B and C ports, and the A port is connected to the T port.

[0052] The second pressure compensation valve 109 is a three-position six-way valve, wherein the A and B ports thereof are connected to the working ports A2 and B2 respectively, and the C port thereof is connected to the feedback port LS1 through an internal oil passage.

[0053] The initial position of the second pressure compensating valve 109 is in the lower position, and when it is in the lower position, its six ports are respectively cut off; when it is in the middle position, its P port and B port, T port and A port are throttled and connected respectively, and P' port and C port are cut off; when it is in the upper position, its P port and B port, T port and A port, P' port and C port are connected respectively.

[0054] The hydraulically controlled one-way valve 110 is connected between the B port of the second pressure compensation valve 109 and the working port B2. The control end of the hydraulically controlled one-way valve 110 is connected to the B port of the first three-position five-way valve 101. A throttle valve 113, a pressure reducing valve 112 and a first one-way valve 111 are provided between the B port of the first three-position five-way valve 101 and the control end of the hydraulically controlled one-way valve 110, which are connected in sequence, for realizing the retreat of the feed cylinder when the rotary motor is reversed; the control ports K1 and K2 are respectively connected to the B port and the A port of the second three-position five-way valve 108, for realizing the linkage of the working condition control valve 2 when the feed cylinder is extended and retracted.

[0055] The drilling valve body comprises an oil inlet valve plate 114, a rotary valve plate 115, a pressure relief valve plate 116, a one-way relief valve plate 117, a feed valve plate 118 and a tail plate 119 which are connected in sequence by bolts. The oil inlet port P and the oil return port T on the drilling valve body are arranged on the oil inlet valve plate 114. The first three-position five-way valve 101, the first pressure compensation valve 103 and the working ports A1 and B1 are arranged on the rotary valve plate 115. The throttle valve 113 , the pressure reducing valve 112 and the first one-way valve 111 are arranged on the pressure reducing relief valve plate 116; the hydraulically controlled one-way valve 110 and the working port B2 are arranged on the one-way relief valve plate 117; the second three-position five-way valve 108, the second pressure compensating valve 109 and the working port A2 are arranged on the feed valve plate 118, the control ports K1 and K2 are arranged on the tail plate 119, and a return oil port T' is also provided on the tail plate 119, and the return oil port T' is connected to the return oil port T.

[0056] Control ports a1 and b1 are provided on the valve covers at both ends of the rotary valve plate 115 , respectively. The control oil chambers at both ends of the first three-position five-way valve 101 are connected to the control ports a1 and b1 respectively, and are used for an external pilot valve to control the switching of the first three-position five-way valve 101 .

[0057] Control ports a2 and b2 are respectively provided on the valve covers at both ends of the feed valve plate 118 , and the control oil chambers at both ends of the second three-position five-way valve 108 are respectively connected to the control ports a2 and b2 for controlling the switching of the second three-position five-way valve 108 by an external pilot valve.

[0058] A main safety valve 107 is installed on the oil inlet valve plate 114, and the main safety valve 107 is connected between the oil inlet port P and the oil return port T; a first overflow valve 105 is also provided on the pressure reducing overflow valve plate 116, and the first overflow valve 105 is connected between the A port of the first pressure compensating valve 103 and the oil return port T; a second overflow valve 106 is also provided on the one-way overflow valve plate 117, and the second overflow valve 106 is connected between the B port of the second pressure compensating valve 109 and the oil return port T.

[0059] The working condition control valve 2 comprises a control valve body and a first three-position four-way valve 201, a first two-position three-way valve 202, a first three-position six-way valve 203, a second three-position six-way valve 204 and a third three-position five-way valve 205 arranged in the control valve body, wherein the first three-position four-way valve 201, the second three-position six-way valve 204 and the third three-position five-way valve 205 are all manual reversing valves, and the first two-position three-way valve 202 and the first three-position six-way valve 203 are all hydraulically controlled valves;

[0060] An oil inlet P2, an oil return port T2, a feedback port LS2', a linkage port A1', a feedback port LS4, working ports A3, A4, B4, A5 and two control ports K1', K2' are provided on the control valve body. The oil inlet P2 and the oil return port T2 are connected with the working ports A3, A4, B4 and the control oil chamber at one end of the first two-position three-way valve 202 through the first three-position six-way valve 203, that is, the P and T ports of the first three-position six-way valve 203 are connected with the oil inlet P2 and the oil return port T2 through the internal oil passage, respectively, the A port is connected with the working port A4 and the control oil chamber at one end of the first two-position three-way valve 202, the B port is connected with the working port A3, the C port is connected with the working port B4, the working port A3 is used for external chuck, and the working ports A4 and B4 are used for external clamp;

[0061] The linkage port A1' and the feedback port LS2' are respectively connected to the P port and the T port of the first three-position four-way valve 201, and are respectively connected to the working port A1 and the feedback port LS2 through external oil pipes; the A port of the first three-position four-way valve 201 is connected to the P port of the first two-position three-way valve 202 and the control oil chamber at the other end through the internal control oil channel, the B port of the first three-position four-way valve 201 is connected to the T port of the first two-position three-way valve 202 and the oil return port T2 through the control oil channel, and the control oil chamber at one end of the first three-position six-way valve 203 is respectively connected to the A port of the first two-position three-way valve 202 and the second three-position six-way valve 20 The P' port of 4 is connected through the control oil passage, the control oil chamber at the other end of the first three-position six-way valve 203 is connected with the T port of the second three-position six-way valve 204, the P port of the second three-position six-way valve 204 is connected with the oil inlet P2 through the internal oil passage, the second three-position six-way valve 204 is connected with the A, B, and C ports of the third three-position five-way valve 205 through the control oil passage, and the B port is connected with the oil return port T2, the P port and the T port of the third three-position five-way valve 205 are connected with the control ports K1' and K2' through the control oil passage in a one-to-one correspondence, and the control ports K1' and K2' are connected with the control ports K1 and K2 in a corresponding manner using oil pipes.

[0062] When the first three-position six-way valve 203 is in the middle position, its P port is connected to the A and B ports, and the C port is connected to the P' and T ports; when it is in the upper position, its P port is connected to the B and C ports, and the A port is connected to the P' and T ports; when it is in the lower position, the P port is connected to the A port, and the B, C, P' and T ports are connected.

[0063] When the second three-position six-way valve 204 is in the middle position, its P port and B port are blocked, P' port and A port are connected, and T port and C port are connected, so as to realize the linkage of the chuck and the clamp; when it is in the upper position, its P port and P' port are connected, B port and T port are connected, and A and C ports are blocked; when it is in the lower position, its P port and T port are connected, P' port and B port are connected, and A and C ports are blocked, so as to realize the single action of the chuck and the clamp.

[0064] When the third three-position five-way valve 205 is in the middle position, its P port is connected to the A port, the C port is connected to the T port, and the B port is cut off, which is used to realize the drilling action; when it is in the upper position, its P port is connected to the C port, the A port is connected to the T port, and the B port is cut off, which is used to realize the pulling out of the drill rod; when it is in the lower position, its A, B, and C ports are connected to each other, and the P port is cut off from the T port, which is used to realize the intermediate adding of the drill rod.

[0065] The control valve body is further provided with a second three-position four-way valve 212, a second two-position three-way valve 206 and a two-position four-way valve 209, the P port and T port of the second three-position four-way valve 212 are respectively connected to the oil inlet P2 and the oil return port T2, the A port and the B port of the second three-position four-way valve 212 are respectively connected to the two end inlets of a shuttle valve 210 through a first pressure reducing valve 211, and the third port of the shuttle valve 210 is connected to the working port A5, so as to control the operation of the brake;

[0066] The P port of the second two-position three-way valve 206 is connected to the feedback port LS4, the A port is connected to the T port of the two-position four-way valve 209 through the internal control oil passage, and the B port is connected to the T port of the two-position four-way valve 209 through the second pressure reducing valve 207 and the fourth one-way valve 208; it is used to feed back the low oil pressure to the oil pump when adding drill pipe;

[0067] The P port of the two-position four-way valve 209 is connected to the oil inlet P2, the A port is connected to the oil outlet P3 provided on the control valve body, and the B port is connected to the feedback port LS provided on the control valve body; it is used to select the working condition control valve 2 or the external stable valve group to work and feedback the oil pressure to the oil pump.

[0068] The control valve body includes a working condition switching valve plate 213, a clamper single-acting valve plate 214, a control valve plate 215, a brake pressure reducing valve plate 216, an LS pressure reducing valve plate 217 and an LS switching valve plate 218 which are connected in sequence by bolts. The first three-position four-way valve 201 and the first two-position three-way valve 202 as well as the linkage port A1' and the feedback port LS2' are arranged on the working condition switching valve plate 213. The first three-position six-way valve 203 and the second three-position six-way valve 204 as well as the working ports A3, A4, B4 and the return oil port T2 are arranged on the clamper single-acting valve plate 214. On the moving valve plate 214, the third three-position five-way valve 205 and the two control ports K1', K2' are arranged on the control valve plate 215, the second three-position four-way valve 212, the first pressure reducing valve and the corresponding shuttle valve and the working port A5 are arranged on the brake pressure reducing valve plate 216, the second two-position three-way valve 206, the second pressure reducing valve 207 and the fourth one-way valve and the feedback port LS4 are arranged on the LS pressure reducing valve plate 217, and the two-position four-way valve 209, the oil inlet P2, the oil outlet P3 and the feedback port LS are arranged on the LS switching valve plate 218.

[0069] The directional drilling rig load sensitive valve is also provided with a travel control valve 3, which includes a travel valve body, on which a third three-position six-way valve 302, a third pressure compensation valve 301, a fourth three-position six-way valve 304, a fourth pressure compensation valve 303, and an oil inlet P1, an oil return port T1, an oil return port Y, working ports A6, B6 and working ports A7, B7 are provided;

[0070] The oil inlet P1 and the oil return port T1 are connected to the working ports A6 and B6 through the third pressure compensation valve 301 and the third three-position six-way valve 302 connected in sequence, and are used to control the rotation of the travel motor of the crawler on one side of the directional drilling rig; the oil inlet P1 and the oil return port T1 are connected to the working ports A7 and B7 through the fourth pressure compensation valve 303 and the fourth three-position six-way valve 304 connected in sequence, and are used to control the rotation of the travel motor of the crawler on the other side of the directional drilling rig. The third pressure compensation valve 301 and the fourth pressure compensation valve 303 are both three-position three-way valves, and the third three-position six-way valve 302 and the fourth three-position six-way valve 304 are both hydraulically controlled valves.

[0071] The travel valve body is also provided with control ports a3, b3, a4, b4, a feedback port LS3, a first shuttle valve 305 and a second shuttle valve 306. The control oil chambers at both ends of the third three-position six-way valve 302 are communicated with the control ports a3 and b3 respectively, and the control oil chambers at both ends of the fourth three-position six-way valve 304 are communicated with the control ports a4 and b4 respectively, for externally connected pilot valves to control two three-position six-way valves; an inlet at one end of the first shuttle valve 305 is communicated with the control oil chamber at one end of the third pressure compensation valve 301 and the P' port of the third three-position six-way valve 302, and an inlet at the other end is communicated with the outlet of the second shuttle valve 306, the outlet of the first shuttle valve 305 is communicated with the feedback port LS3, and an inlet at one end of the second shuttle valve 306 is communicated with the control oil chamber at one end of the fourth pressure compensation valve 303 and the P' port of the fourth three-position six-way valve 304; the feedback port LS3 and the feedback port LS1 are communicated with the feedback port LS4 through a third shuttle valve 4, for feeding back oil pressure to the oil pump.

[0072] The initial positions of the third three-position six-way valve 302 and the fourth three-position six-way valve 304 are in the middle position, and when in the middle position, the P port is cut off, and the P' port and the T port are connected to the A, B, and C ports; when in the upper position, the P port is connected to the B port, and is throttled with the P' port and the C port, and the A port is connected to the T port; when in the lower position, the P port is connected to the A port, and is throttled with the P' port and the C port, and the B port is connected to the T port.

[0073] The travel valve body is formed by connecting four valve plates in sequence. The oil inlet P1 and the oil return port T1 are arranged on the first valve plate 309. The first valve plate is also provided with a third relief valve 307, which is connected between the oil inlet P1 and the oil return port T1; the third three-position six-way valve 302, the third pressure compensation valve 301 and the first shuttle valve 305 as well as the working ports A6, B6 and the control ports a3, b3 are arranged on the second valve plate 310; the fourth three-position six-way valve 304, the fourth pressure compensation valve 303 and the second shuttle valve 306 as well as the working ports A7, B7 and the control ports a4, b4 are arranged on the third valve plate 311; the third pressure reducing valve 308 is arranged on the fourth valve plate 312, which is connected between the oil inlet P1 and the pilot oil port X. The oil drain port of the third pressure reducing valve 308 is communicated with the oil return port Y. The pilot oil port X is arranged on the fourth valve plate and is used for the oil inlet of the external pilot valve.

[0074] When working, the oil inlets P, P1 and P2 are interconnected through oil pipes and connected to the output port of the variable oil pump, the feedback port LS is connected to the feedback port of the oil pump through an oil pipe, the return oil ports T, T1, T2 and Y are connected to the oil tank through oil pipes, and the pilot oil port X is connected to two pilot valve groups through a manual two-position four-way valve 5, wherein the two working ports of the first pilot valve group 6 are respectively connected to the control ports a3 and b3 and the control ports a4 and b4 to control the reversing of the travel control valve; the two working ports of the second pilot valve group 7 are respectively connected to the control ports a1 and b1 and the control ports a2 and b2 to control the operation of the drilling valve 1. The oil outlet P3 is externally connected to the stabilizing valve group 8 through an oil pipe.

[0075] In the initial state, the first three-position five-way valve 101 in the drilling valve 1 is in the middle position, and the first pressure compensation valve 103 is in the lower position. At this time, the rotary motor of the power head does not rotate; the second three-position five-way valve 108 is in the middle position, and the second pressure compensation valve 109 is in the lower position, and the feed cylinder does not move; the first three-position four-way valve 201 in the working condition control valve 2 is in the middle position, and the first two-position three-way valve 202 is in the lower position, and the working condition control valve 2 is in the directional state; the second three-position six-way valve 204 is in the middle position, and the working condition control valve 2 is in the linkage state; the third three-position five-way valve 205 is in the middle position, and the working condition control valve 2 is in the drilling state; the two-position four-way valve 209 is in the upper position, and the working condition control valve 2 is in the drilling or walking state; the third and fourth three-position six-way valves 304 in the walking control valve are both in the middle position, and the third and fourth pressure compensation valves are both in the upper position, and the crawlers on both sides of the directional drilling rig are fixed.

[0076] When the directional drilling rig needs to move, the third, third, and fourth six-way valves 302 and 304 of the travel control valve are switched to the lower position through the pilot valve. At this time, the third and fourth three-way valves are switched to the middle position, and the oil inlet P1 is connected with the working ports A6 and A7 respectively, so that the travel motors of the crawlers on both sides of the directional drilling rig can be driven to rotate forward, so that the directional drilling rig can move forward; conversely, the third, third, and fourth three-way valves 302 and 304 of the travel control valve are switched to the upper position, and the oil inlet P1 is connected with the working ports B6 and B7 respectively, so that the travel motors of the crawlers on both sides of the directional drilling rig can be driven to reverse, so that the directional drilling rig can move backward.

[0077] When the directional drilling rig needs to extend the bracket, the two-position four-way valve 209 of the control condition control valve 2 is in the lower position. At this time, the condition control valve 2 does not work, and the oil inlet P2 enters the stabilizing valve group 8 through the two-position four-way valve 209. The stabilizing valve group works. The stabilizing valve group 8 is composed of multiple three-position six-way valves connected in parallel. By reversing the three-position six-way valves in the stabilizing valve group, the corresponding bracket can be controlled to extend;

[0078] When the directional drilling rig needs to work, the two-position four-way valve 209 of the working condition control valve 2 is switched to the upper position. At this time, the working condition control valve 2 works, and the stabilizing valve group does not work. Because the drill rod of the directional drilling rig is a special drill rod, when the directional drilling rod performs drilling / retracting action, the drill rod does not rotate, but only moves forward or backward. When the directional drilling rig needs to perform ordinary drilling action, the drill rod needs to be replaced with an ordinary drill rod for operation.

[0079] The following takes the control work of a directional drilling rig during directional drilling as an example.

[0080] When the directional drilling rig needs to drill, the first three-position four-way valve 201 of the working condition control valve 2 is in the middle position, and the second three-position six-way valve 204 is in the middle position. At this time, the directional drilling rig is in a directional linkage state; the second three-position six-way valve of the working condition control valve can be used to control whether the state between the drill pipe and the clamp and the chuck is linked or not, which is divided into three working states: linkage state, single-action state I (clamp clamp, chuck open) and single-action state II (chuck clamp, clamp open); the drill pipe and the clamp and the chuck are linked, and the state of the chuck and the clamp can be adjusted by controlling the state of the drill pipe, thereby simplifying the operation steps; it can also be switched to a single-action state as needed, and the state of the chuck and the clamp can be changed manually to facilitate control requirements under special circumstances.

[0081] During drilling, the third three-position five-way valve 205 of the working condition control valve 2 is in the middle position, which is the drilling state. The second three-position five-way valve 108 of the drilling valve 1 is in the lower position. At this time, the oil cylinder moves forward, and oil is discharged from the control port K1. It enters the control oil chamber at the upper end of the first three-position six-way valve 203 through the third three-position five-way valve 205 and the second three-position six-way valve 204 of the working condition control valve 2 in sequence, and the first three-position six-way valve 203 is switched to the upper position. At this time, the oil entering from the oil inlet P2 enters the chuck and the clamp through the first three-position six-way valve 203 and the working ports A3 and B4, so that the chuck is clamped and the clamp is opened, and drilling can be achieved.

[0082] When the directional drilling rig needs to change the drilling direction, the first three-position four-way valve 201 of the working condition control valve 2 is switched to the lower position, and the directional drilling rig is in the track change state at this time; the first three-position five-way valve 101 of the drilling valve 1 is controlled by the pilot valve to be in the upper position, and the oil enters the rotary motor and the working condition control valve 2 through the oil inlet P, the first three-position five-way valve 101, the first pressure compensation valve 103, and the working port A1 in sequence, driving the rotary motor to rotate forward, and at the same time, the first two-position three-way valve 202 is switched to the upper position. At this time, the oil entering from the working port A1' enters the control oil chamber at the upper end of the first three-position six-way valve 203 through the first three-position four-way valve 201 and the first two-position three-way valve 202, so that it is switched to the upper position. At this time, the drill rod rotates slowly, and at the same time, the oil entering from the oil inlet P2 enters the chuck and the clamp through the first three-position six-way valve 203 and the working ports A3 and B4, so that the chuck is clamped and the clamp is opened, so that the drilling direction can be changed;

[0083] When the drill rod is turned to the required angle, the first three-position five-way valve 101 of the drilling valve 1 is switched to the middle position to stop the rotating motor; the first three-position four-way valve 201 of the working condition control valve 2 is switched to the middle position to put it in a directional state, and then the second three-position five-way valve 108 of the drilling valve 1 is switched to the lower position. At this time, the oil flows out from the control port K1 to the working condition control valve 2, and enters the control oil chamber at the upper end of the first three-position six-way valve 203 through the third three-position five-way valve 205 and the second three-position six-way valve 204 in turn. The first three-position six-way valve 203 is switched to the upper position. At this time, the chuck is clamped, the clamp is opened, and the directional drilling rig can drill normally.

[0084] When the directional drilling rig needs to add a drill rod, the third three-position five-way valve 205 of the working condition control valve 2 is switched to the lower position, and the first three-position four-way valve 201 is switched to the middle position in the directional state. At this time, the control oil chambers at both ends of the first three-position six-way valve 203 are connected to the oil return port T2 through the second three-position six-way valve 204 and the third three-position five-way valve 205, so that the first three-position six-way valve 203 returns to the middle position, and the working ports A3 and A4 are connected to the oil inlet P2 respectively, so that the chuck is clamped and the clamper is clamped; then the second two-position three-way valve is switched to the middle position. Valve 206 is switched to the lower position, controlling the first three-position five-way valve 101 of the drilling valve 1 to be in the upper position, at which time the rotary motor is driven to rotate forward, and at the same time the feedback oil passes through the second one-way valve 102, the feedback port LS1, the third shuttle valve and the feedback port LS4 in sequence to reach the second two-position three-way valve 206, and is fed back to the oil pump through the second two-position three-way valve 206, the second pressure reducing valve 207, the fourth one-way valve and the two-position four-way valve 209; the low-pressure output of the oil pump drives the rotary motor to rotate at a low speed, so that the drill rod can be put on the front drill rod.

[0085] When the drill pipe of the directional drilling rig needs to retreat, the third three-position five-way valve 205 of the working condition control valve 2 is switched to the upper position, and the first three-position four-way valve 201 is switched to the middle position. At this time, the valve body is in the drilling state, and the second three-position five-way valve 108 of the drilling valve 1 is controlled by the pilot valve to be in the upper position. The oil reaches the working port A2 through the oil inlet P and the second three-position five-way valve 108 and enters the feed cylinder to control the feed cylinder to retreat; at the same time, the oil enters the third three-position five-way valve 205 of the working condition control valve 2 from the control port K2, and enters the control oil chamber at the upper end of the first three-position six-way valve 203 through the third three-position five-way valve 205 and the second three-position six-way valve 204 in sequence, so that the first three-position six-way valve 203 is switched to the upper position, and the oil entering from the oil inlet P2 can enter the chuck and the clamp through the first three-position six-way valve 203 and the working ports A3 and B4, so that the chuck is clamped and the clamp is opened, and the drill pipe can be retreated.

[0086] When the directional drilling rig needs to unload the drill pipe, the third three-position five-way valve 205 of the working condition control valve 2 is switched to the upper position, and the first three-position four-way valve 201 is switched to the middle position. At this time, the oil in the control oil chamber at both ends of the first three-position six-way valve 203 of the working condition control valve 2 passes through the second three-position six-way valve 204 and the third three-position five-way valve 205 and then enters the second three-position five-way valve 108 of the drilling valve 1 from the control ports K1 and K2 respectively and flows to the oil return port T, so that the first three-position six-way valve 203 of the working condition control valve 2 is in the middle position, so that the working ports A3 and A4 are respectively connected to the inlet port. The oil port P2 is connected to clamp the chuck and the clamper; the first three-position five-way valve 101 of the drilling valve 1 is controlled by the pilot valve to be in the lower position, so that the oil entering the oil inlet P passes through the first three-position five-way valve 101 to reach the working port B1, and the oil simultaneously reaches the working port A2 and the control end of the hydraulically controlled one-way valve 110 from the throttle valve, the pressure reducing valve and the first one-way valve, so that the hydraulically controlled one-way valve 110 is reversely conducted, so that the working port B2 is connected to the return oil port T through the second three-position five-way valve 108 to unload the oil. At this time, the motor reverses and the cylinder retreats, and the drill rod unloading operation can be performed.

[0087] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A load-sensitive valve for a directional drilling rig, comprising a drilling valve and a working condition control valve, characterized in that: The drilling valve includes a drilling valve body and a first, third, five-way valve, a second, third, five-way valve, a first pressure compensating valve, a second pressure compensating valve, and a hydraulically controlled one-way valve arranged in the drilling valve body. An oil inlet P, an oil return port T, feedback ports LS1 and LS2, working ports A1, B1, A2, B2, and control ports K1 and K2 are arranged on the drilling valve body. The oil inlet P and the oil return port T are connected to the working ports A1 and B1 through the first, third, five-way valve and the first pressure compensating valve connected in sequence, so as to control the rotation of the rotary motor of the power head; the oil inlet P and the oil return port T are connected to the working ports A2 and B2 through the second, third, five-way valve and the second pressure compensating valve connected in sequence, so as to control the extension and retraction of the feed cylinder; the control oil chambers at both ends of the first pressure compensating valve and the second pressure compensating valve are connected to the feedback ports LS1 and LS2 respectively; The C port of the first three-position five-way valve is connected to the feedback port LS2 through the third one-way valve, the hydraulic one-way valve is connected between the second pressure compensation valve and the working port B2, and the control end of the hydraulic one-way valve is connected to the B port of the first three-position five-way valve, so as to realize the retreat of the feed cylinder when the rotary motor is reversed; the control ports K1 and K2 are respectively connected to the B port and the A port of the second three-position five-way valve, so as to realize the linkage of the working condition control valve when the feed cylinder is extended and retracted; The working condition control valve includes a control valve body and a first three-position four-way valve, a first two-position three-way valve, a first three-position six-way valve, a second three-position six-way valve and a third three-position five-way valve arranged in the control valve body. An oil inlet P2, an oil return port T2, a feedback port LS2', a linkage port A1', working ports A3, A4, B4, A5 and two control ports K1', K2' are arranged on the control valve body. The oil inlet P2 and the oil return port T2 are connected with the working ports A3, A4, B4 and the control oil chamber at one end of the first two-position three-way valve through the first three-position six-way valve. The linkage port A1' and the feedback port LS2' are connected with the P port and the T port of the first three-position four-way valve respectively, and are connected with the working port A1 and the feedback port LS2 respectively through oil pipes. The A port of the first two-position four-way valve is connected with the P port of the first two-position three-way valve and the control oil chamber at the other end, the B port of the first three-position four-way valve is connected with the T port of the first two-position three-way valve and the oil return port T2, the control oil chamber at one end of the first three-position six-way valve is connected with the A port of the first two-position three-way valve and the P' port of the second three-position six-way valve respectively, the control oil chamber at the other end of the first three-position six-way valve is connected with the T port of the second three-position six-way valve, the P port of the second three-position six-way valve is connected with the oil inlet P2, the second three-position six-way valve is connected with the A, B and C ports of the third three-position five-way valve correspondingly, and the B port is connected with the oil return port T2, and the P port and T port of the third three-position five-way valve are connected with the control ports K1 and K2 correspondingly through the control ports K1' and K2' using oil pipes.

2. The directional drilling rig load sensing valve according to claim 1, characterized in that: The drilling valve body includes an oil inlet valve plate, a rotary valve plate, a pressure reducing relief valve plate, a one-way relief valve plate, a feed valve plate and a tail plate which are connected in sequence; the oil inlet port P and the oil return port T on the drilling valve body are arranged on the oil inlet valve plate; the first three-position five-way valve, the first pressure compensating valve and the working ports A1 and B1 are arranged on the rotary valve plate; the hydraulically controlled one-way valve and the working port B2 are arranged on the one-way relief valve plate; the second three-position five-way valve, the second pressure compensating valve and the working port A2 are arranged on the feed valve plate, and the control ports K1 and K2 are arranged on the tail plate.

3. The directional drilling rig load sensitive valve according to claim 2, characterized in that: A throttle valve, a pressure reducing valve and a first check valve are sequentially connected between the B port of the first three-position five-way valve and the control end of the hydraulically controlled check valve. The throttle valve, the pressure reducing valve and the first check valve are arranged on the pressure reducing and overflow valve plate.

4. The directional drilling rig load sensitive valve according to claim 2 or 3, characterized in that: Control ports a1 and b1 are respectively provided on the valve covers at both ends of the rotary valve plate. The control oil chambers at both ends of the first three-position five-way valve are respectively connected to the control ports a1 and b1 for controlling the switching of the first three-position five-way valve by an external pilot valve.

5. The directional drilling rig load sensing valve according to claim 2, characterized in that: Control ports a2 and b2 are respectively provided on the valve covers at both ends of the feed valve plate, and the control oil chambers at both ends of the second three-position five-way valve are respectively connected to the control ports a2 and b2 for controlling the switching of the second three-position five-way valve by an external pilot valve.

6. The directional drilling rig load sensing valve according to claim 1, characterized in that: A second three-position four-way valve, a second two-position three-way valve and a two-position four-way valve are also provided in the control valve body of the working condition control valve, the P port and the T port of the second three-position four-way valve are respectively connected to the oil inlet P2 and the oil return port T2, the A port and the B port of the second three-position four-way valve are respectively connected to the two ends of a shuttle valve through a first pressure reducing valve, and the third port of the shuttle valve is connected to the working port A5 for controlling the operation of the brake; The P port of the second two-position three-way valve is connected to the feedback port LS4 provided on the control valve body, the A port is connected to the T port of the two-position four-way valve, and the B port is connected to the T port of the two-position four-way valve through the second pressure reducing valve and the fourth one-way valve; The P port of the two-position four-way valve is connected to the oil inlet P2, the A port is connected to the oil outlet P3 provided on the control valve body, and the B port is connected to the feedback port LS provided on the control valve body; it is used to select the working condition control valve or the external stable valve group to work and feedback the oil pressure to the oil pump.

7. The directional drilling rig load sensing valve according to claim 6, characterized in that: The control valve body includes a working condition switching valve plate, a clamp single-acting valve plate, a control valve plate, a brake pressure reducing valve plate, an LS pressure reducing valve plate and an LS switching valve plate which are connected in sequence; the first three-position four-way valve and the first two-position three-way valve are arranged on the working condition switching valve plate; the first three-position six-way valve and the second three-position six-way valve are arranged on the clamp single-acting valve plate; the third three-position five-way valve and two control ports K1', K2' are arranged on the control valve plate; the second three-position four-way valve, the first pressure reducing valve and the corresponding shuttle valve are arranged on the brake pressure reducing valve plate; the second two-position three-way valve, the second pressure reducing valve and the fourth one-way valve are arranged on the LS pressure reducing valve plate; the two-position four-way valve, the oil inlet P2 and the feedback port LS are arranged on the LS switching valve plate.

8. The directional drilling rig load sensing valve according to claim 1, characterized in that: A travel control valve is also provided, which includes a travel valve body, on which a third three-position six-way valve, a third pressure compensation valve, a fourth three-position six-way valve, a fourth pressure compensation valve, an oil inlet P1, an oil return port T1, working ports A6, B6 and working ports A7, B7 are provided; The oil inlet P1 and the oil return port T1 are connected to the working ports A6 and B6 through the third pressure compensation valve and the third three-position six-way valve connected in sequence, and are used to control the rotation of the travel motor of the crawler on one side of the directional drilling rig; the oil inlet P1 and the oil return port T1 are connected to the working ports A7 and B7 through the fourth pressure compensation valve and the fourth three-position six-way valve connected in sequence, and are used to control the rotation of the travel motor of the crawler on the other side of the directional drilling rig.

9. The directional drilling rig load sensing valve according to claim 8, characterized in that: The travel valve body is also provided with control ports a3, b3, a4, b4, a feedback port LS3, a first shuttle valve and a second shuttle valve. The control oil chambers at both ends of the third three-position six-way valve are communicated with the control ports a3 and b3 respectively, and the control oil chambers at both ends of the fourth three-position six-way valve are communicated with the control ports a4 and b4 respectively, which are used for an external pilot valve to control the two three-position six-way valves; an inlet at one end of the first shuttle valve is communicated with the control oil chamber at one end of the third pressure compensation valve and the P' port of the third three-position six-way valve, and an inlet at the other end is communicated with the outlet of the second shuttle valve, and the outlet of the first shuttle valve is communicated with the feedback port LS3, and an inlet at one end of the second shuttle valve is communicated with the control oil chamber at one end of the fourth pressure compensation valve and the P' port of the fourth three-position six-way valve; The feedback port LS3 and the feedback port LS1 are connected to the feedback port LS4 via a third shuttle valve for feeding back the oil pressure to the oil pump.

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