JP4798710B2 - Combine - Google Patents

Description

  The present invention relates to the amount of pressure oil supplied when supplying hydraulic oil from a hydraulic pump to a hydraulic mechanism for lifting and lowering and the amount of drain when discharging hydraulic oil from the hydraulic mechanism for lifting and lowering a cutting pressure. The present invention relates to a combine configured to be able to control an operating speed of the hydraulic mechanism for lifting and lowering by adjusting by position control.

  In the combine, a cutting part disposed in front of the machine frame can be raised and lowered with respect to the machine frame. Specifically, the combine is provided with a hydraulic mechanism for lifting and lowering as a hydraulic actuator for raising and lowering the cutting part. By controlling supply and discharge of hydraulic oil to and from the hydraulic mechanism for lifting and lowering, the cutting part is It goes up and down with respect to the machine frame.

By the way, the raising / lowering speed of the cutting part depends on the supply / discharge amount of the hydraulic oil to the cutting raising / lowering hydraulic mechanism. That is, if the amount of hydraulic oil supplied from the hydraulic pump as a hydraulic source to the cutting lift hydraulic mechanism is increased, the lifting speed of the cutting unit increases, and the amount of hydraulic oil discharged from the cutting lift hydraulic mechanism If is set to be large, the lowering speed of the mowing part increases.
Thus, the operating speed of the hydraulic actuator can be controlled by adjusting the pressure oil supply amount when supplying the pressure oil from the hydraulic pump to the hydraulic actuator and the drain amount when discharging the pressure oil from the hydraulic actuator. However, as such a hydraulic actuator operation speed control structure, a structure using a pilot pressure operation type variable throttle valve has been proposed (see Patent Document 1 below).

Specifically, the hydraulic mechanism described in Patent Document 1 includes a supply line that supplies pressure oil from a hydraulic pump to a hydraulic actuator, a direction switching valve that selectively connects or disconnects the supply line, and the direction switching valve. And a drain line communicating with the supply line between the hydraulic actuators, a pilot pressure actuated variable throttle valve inserted in the drain line, and a pilot for applying a pilot pressure to the variable throttle valve And an electromagnetic proportional pressure reducing valve for adjusting the pressure oil supply to the pilot line.
The conventional hydraulic mechanism can adjust the pressure oil supply amount to the actuator and the drain amount from the actuator without inserting the electromagnetic proportional pressure reducing valve in the supply / discharge oil passage of the hydraulic actuator. This is useful in that the operating speed of the hydraulic actuator can be controlled within a sufficient range without increasing the size of the pressure reducing valve.

However, in the conventional hydraulic mechanism, since a part of the pressure oil in the supply line is taken out and supplied to the primary side of the electromagnetic proportional pressure reducing valve, the variable throttle valve is operated. Regardless of whether or not, there is a problem that a load is always applied to the hydraulic pump.
That is, as shown in FIG. 18, the conventional hydraulic mechanism branches a part of the pressure oil from the supply line to the pilot pressure extraction line via the flow rate adjusting valve, and reliefs the pressure oil in the pilot pressure extraction line. The pressure is regulated by the valve, and is supplied to the primary side of the electromagnetic proportional pressure reducing valve.
In such a configuration, even when the variable throttle valve is not operated, a certain amount of pressure oil always flows through the pilot pressure extraction line, and an unnecessary load is constantly applied to the hydraulic pump.

Further, in the conventional configuration, the flow rate adjusting valve for taking out the pressure oil to the pilot pressure take-out line and the relief valve for setting the oil pressure of the pilot pressure take-out line are necessary, and the cost due to an increase in the number of parts is required. There is also the problem of incurring high and large size.
JP-A-6-280815

  The present invention has been made in view of the prior art, and by controlling the position of a pilot pressure actuated variable throttle valve, the amount of pressure oil supplied from the hydraulic pump to the cutting lift hydraulic mechanism and the cutting lift hydraulic pressure. An object of the present invention is to provide a combine capable of adjusting the drain amount from the mechanism, which can reduce the load of the hydraulic pump, and can reduce cost and size by reducing the number of parts. .

  In order to solve the above-described problems, the present invention provides a traveling system HST that is operatively connected to an engine, a charge pump that is operatively connected to the engine, and a supply of hydraulic oil from the charge pump to the traveling system HST. A charge line regulated to a predetermined pressure, an auxiliary pump operatively connected to the engine, a cutting lift hydraulic mechanism that lifts and lowers a cutting part by pressure oil from the auxiliary pump, and a lifting lift from the auxiliary pump A supply line for supplying pressure oil to the hydraulic mechanism; a direction switching valve for selectively communicating or blocking the supply line; and a drain communicated with the supply line between the direction switching valve and the cutting lift hydraulic mechanism A pilot pressure actuated variable throttle valve inserted in the drain line, and a pilot for applying pilot pressure to the variable throttle valve And an electromagnetic proportional pressure reducing valve for adjusting the pressure oil supply to the pilot line, and the position control of the variable throttle valve is performed by adjusting the pressure oil supply to the pilot line by the electromagnetic proportional pressure reducing valve. A combiner configured to control an operating speed of the cutting lift hydraulic mechanism, the combiner configured to supply pressure oil from the charge line to the pilot line via the electromagnetic proportional pressure reducing valve. I will provide a.

  Preferably, the charge pump uses oil stored in the transmission case as an oil source, excess oil in the charge line is returned to the mission case, and the auxiliary pump uses oil stored in the counter case as an oil source. The drain oil from the cutting lift hydraulic mechanism and the pressure oil from the charge line that is blocked from being supplied to the pilot line by the electromagnetic proportional pressure reducing valve are configured to be returned to the counter case. Furthermore, the counter case and the mission case can be fluidly connected via a communication line.

According to the present invention, the pilot line that applies pilot pressure to the pilot pressure actuated variable throttle valve that controls the operating speed control of the hydraulic mechanism for lifting and lowering is adjusted to a predetermined pressure in order to supply hydraulic oil to the HST. Since the pressure oil is supplied from the pressed charge line, the load on the hydraulic pump serving as the hydraulic pressure source of the cutting lift hydraulic mechanism can be reduced.
Compared to the conventional configuration where pressure oil for flowing from the supply line for supplying pressure oil to the hydraulic actuator from the hydraulic pump is taken out to the pilot line, the flow control valve and pilot pressure setting are used. The relief valve can be eliminated. Therefore, cost reduction and size reduction can be achieved by reducing the number of parts.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 3 are a perspective view, a right side view, and a transmission schematic diagram of a combine 1 to which an embodiment of the present invention is applied, respectively.

  As shown in FIGS. 1 to 3, the combine 1 includes a machine frame 3, an engine 21 supported by the machine frame 3, and a pair of left and right crawler traveling units connected to the machine frame 3. 2, a traveling transmission 100 that changes the rotational power from the engine 21 and outputs it to the pair of traveling units 2, and a cutting that is supported by the machine frame 3 so as to be movable up and down in front of the machine frame 3. Part 7, a hydraulic mechanism 11 for raising and lowering the cutting part 7, a feed chain part 5 for conveying cereals harvested by the cutting part 7 backward on the left side of the machine frame 3, A threshing portion 4 disposed on the left portion of the machine frame 3 and a lower portion of the threshing portion 4 so as to perform the threshing process on the cereals conveyed by the feed chain portion 5. A swing sorter (not shown), a work machine system transmission 200 for transmitting power from the engine 21 to the reaping part 7, the threshing part 4 and the swing sorter, and the machine frame 3 An operation unit 18 disposed in the right front portion, and a storage unit 15 that accommodates the grains selected by the swing selection unit, the storage unit 15 disposed behind the operation unit 18. I have.

4 and 5 show a front left side view and a front view of the machine in the combine 1, respectively. FIG. 6 is a partial left side view of the vicinity of the engine 21, the traveling transmission 100, and the work implement transmission 200.
As shown in FIGS. 4 to 6, the traveling transmission 100 is disposed between the pair of traveling units 2 at a position closer to the front of the machine frame 3.

7 to 9 are a transmission schematic diagram, a plan view, and a longitudinal rear view of the traveling transmission 100, respectively.
As shown in FIGS. 7 to 9, the traveling transmission 100 combines the traveling system HST (the traveling HST 120 and the turning HST 130) operatively connected to the engine 21 and the outputs of both the HSTs 120 and 130. A traveling system transmission mechanism that transmits to the pair of traveling system output shafts 55a and 55b, and an oil storage mission case 110 that accommodates the traveling system transmission mechanism are provided.

  The traveling HST 120 and the turning HST 130 are supported by the transmission case 110 while being operatively connected to the engine 21, as shown in FIGS.

FIG. 10 shows a hydraulic circuit diagram of the traveling transmission 100 and the work machine transmission 200.
7 to 10, the traveling HST 120 includes a traveling pump shaft 121, a traveling hydraulic pump body 122 supported on the traveling pump shaft 121 so as not to rotate relative to the traveling pump shaft 121, and the traveling hydraulic pump. A travel hydraulic motor main body 123 fluidly connected to the main body 122 via a pair of travel hydraulic lines 400, a travel hydraulic motor shaft 124 that supports the travel hydraulic motor main body 123 so as not to be relatively rotatable, and the travel A traveling movable swash plate 125 that changes the amount of oil supplied to and discharged from at least one of the hydraulic pump body 122 and the traveling hydraulic motor body 123 is provided.
In the present embodiment, both the traveling hydraulic pump main body 122 and the traveling hydraulic motor main body 123 are variable displacement types. Therefore, the traveling HST 120 includes a traveling pump-side movable swash plate 125a and a traveling motor-side movable swash plate 125b as the traveling movable swash plate 125.

  As shown in FIGS. 7 to 10, the turning HST 130 includes a turning pump shaft 131, a turning hydraulic pump main body 132 supported on the turning pump shaft 131 so as not to rotate relative to the turning pump shaft 131, and the turning hydraulic pump. A turning hydraulic motor main body 133 fluidly connected to the main body 132 via a pair of turning hydraulic lines 410, a turning hydraulic motor shaft 134 that supports the turning hydraulic motor main body 133 so as not to be relatively rotatable, and the turning hydraulic motor shaft 134. A turning movable swash plate 135 that changes the amount of oil supplied to and discharged from at least one of the hydraulic pump main body 132 and the turning hydraulic motor main body 134 (in the illustrated form, the turning hydraulic pump main body 132) is provided.

  The traveling pump-side movable swash plate 125a and the traveling motor-side movable swash plate 125b are tilted via a traveling hydraulic servo mechanism 30 that operates according to the operation amount of the traveling operation member 35, and the turning movable swash plate 125b. The swash plate 135 is tilted via a turning hydraulic servo mechanism 40 that operates according to the operation amount of the turning operation member 45 (see FIG. 10).

The traveling HST 120 and the turning HST 130 are supported on the outer surface of the transmission case 110 with the pump shafts 121 and 131 and the motor shafts 123 and 133 protruding into the internal space of the transmission case 110. Yes.
Specifically, as shown in FIG. 7, the traveling transmission 100 includes an input shaft 140 supported by the transmission case 110 in a state in which the traveling transmission 100 is operatively connected to the engine 21, and the input shaft 140. Is connected to the traveling pump shaft 121 so that the traveling input transmission mechanism 150 is accommodated in the transmission case 110, and the turning input transmission mechanism 160 is operatively connected to the turning pump shaft 131. And.

  As shown in FIG. 7, the traveling transmission mechanism includes a pair of first and second planetary gear mechanisms 170a and 170b, and the rotational power of the traveling motor shaft 124 as the first and second planetary gear mechanisms 170a, b for transmitting in the same rotational direction to the traveling output transmission mechanism 180 and the rotational power of the turning motor shaft 134 to one of the first and second planetary gear mechanisms 170a and 170b in the forward rotation direction and to the other. And a turning output transmission mechanism 190 for transmitting in the reverse direction.

The first and second planetary gear mechanisms 170a, b transmit the rotational power from the traveling output transmission mechanism 180 and the turning output transmission mechanism 190 to the first and second traveling system output shafts 55a, 55b, respectively. Is configured to do.
Specifically, the first and second planetary gear mechanisms 170a, 170b are respectively a sun gear 171, a planetary gear 172 meshed with the sun gear 171 so as to revolve around the sun gear 171, and the planetary gear 172. The carrier 173 revolves around the sun gear 171 together with the planetary gear 172, and the internal gear 174 meshes with the planetary gear 172.
In the present embodiment, the traveling output transmission mechanism 180 is operatively connected to the internal gear 174, and the turning output transmission mechanism 190 is operatively connected to the sun gear 171, and the carrier gear 173 corresponds to the carrier 173. The traveling system output shafts 55a and 55b are operatively connected.

The travel output transmission mechanism 180 includes a travel output shaft 181 operatively connected to the travel motor shaft 124, a branch shaft 185 operatively coupled to the travel output shaft 181, and rotational power of the branch shaft 185. Is transmitted to the internal gear 174 of the first planetary gear mechanism 170a, and the rotational power of the branch shaft 185 is transmitted to the internal gear 174 of the second planetary gear mechanism 170b. And a second traveling output gear train 186b.
The first and second traveling output gear trains 186a and 186b have the same transmission direction and transmission ratio.

In this embodiment, the traveling output transmission mechanism 180 includes a traveling brake device 182 that can operatively apply a braking force to the traveling motor shaft 124 in addition to the above-described configuration.
In the present embodiment, the traveling brake device 182 is disposed between the traveling output shaft 181 and the branch shaft 185 in the power transmission direction.
Specifically, the traveling brake device 182 receives a rotational power from the traveling output shaft 181 and outputs it to the branch shaft 185, and selectively applies a braking force to the brake shaft 183. And a brake unit 184 that can be added.

Further, in the present embodiment, the traveling output transmission mechanism 180 includes a sub-transmission mechanism 187 that shifts the rotational power of the traveling motor shaft 124 in multiple stages.
In the present embodiment, the sub-transmission mechanism 187 is configured to be capable of multi-stage shifting between the travel output shaft 181 and the travel brake shaft 183.

The turning output transmission mechanism 190 includes a turning output shaft 191 operatively connected to the turning motor shaft 134, a common shaft 192 operatively connected to the turning output shaft 191, and rotational power of the common shaft 192. Is transmitted to the sun gear 171 of the first planetary gear mechanism 170a, and a second swing is transmitted to transmit the rotational power of the common shaft 192 to the sun gear 171 of the second planetary gear mechanism 170b. Output gear train 193b.
The first and second turning output gear trains 193a and 193b have the same transmission ratio, but are configured so that the transmission directions are opposite to each other.

Reference numeral 194 in FIG. 7 is a turning brake device that can operatively apply a braking force to the turning motor shaft 134, and reference numeral 195 denotes the turning output shaft 134 to the common shaft 192. A clutch device that engages or shuts off power transmission.
Further, reference numeral 155 in FIG. 7 is a cooling fan that is rotationally driven by the power from the input shaft 140, and reference numeral 810 is a charge pump described later.

As shown in FIGS. 4 to 6, the work machine transmission 200 is supported by the machine frame 3 on the vehicle rear side from the traveling transmission 100.
In FIG. 11, the transmission schematic diagram of the said working machine type transmission 200 is shown.
FIGS. 12 and 13 show a partially longitudinal side view of the work machine transmission 200 and a partially vertical rear view of the work machine transmission 200 taken along line XIII-XIII in FIG. 12, respectively.

  The work machine transmission 200 receives constant speed rotational power from the engine 21 and vehicle speed synchronized rotational power from the traveling system HST 120, and constant speed rotational power to the threshing unit 4 and the swing sorting unit. And a constant speed rotational power or a vehicle speed synchronized rotational power can be selectively output to the mowing unit 7 and the feed chain unit 5.

  Specifically, as shown in FIGS. 3 to 10, the work machine transmission 200 includes a counter case 210 that can store oil, an oil passage block 215 that closes an upper opening of the counter case, and a threshing clutch. A constant speed input shaft 220 that is operatively connected to the engine 21 via a mechanism 50, a threshing hydraulic mechanism 230 that systematically removes the threshing clutch mechanism 50, and a threshing portion that is operatively connected to the constant speed input shaft 220. A threshing output shaft 221 that outputs rotational power toward the four handling cylinders 6, a constant speed transmission shaft 223 that is operatively connected to the constant speed input shaft 220, and a motor shaft 124 of the traveling HST 120. The vehicle speed tuning input shaft 224, the transmission transmission shaft 225, and the vehicle speed tuning input shaft 224 or the constant speed transmission shaft 223 are selectively engaged with the transmission transmission shaft 225. The cutting transmission mechanism 240, 250 to be operated, the cutting output shaft 226 that is operatively connected to the transmission transmission shaft 225 and outputs the cutting force to the cutting unit 7, and the cutting hydraulic mechanism 260a, which operates the cutting transmission mechanism 240, 250, b, an FC transmission mechanism 280 that combines the rotational power of the constant speed transmission shaft 223 and the rotational power of the transmission transmission shaft 225, and an output portion of the FC transmission mechanism 280, and is operatively connected to the feed chain portion 5 And a feed chain output shaft 227 for outputting rotational power.

In the present embodiment, the constant speed input shaft 220 and the threshing output shaft 221 are integrally formed by a single shaft as shown in FIG.
That is, the single shaft is supported by the counter case 210 along the longitudinal direction of the vehicle so that one end protrudes backward from the counter case 210 and the other end protrudes forward from the counter case 210. The one end portion forms an input end portion that is operatively connected to the engine 21, and the other end portion forms an output end portion that outputs rotational power toward the threshing portion 4.

A constant speed input pulley 201 is attached to the constant speed input shaft 220 (the one end portion of the single shaft), and the engine 21 is interposed via a constant speed input belt 202 wound around the constant speed input pulley 201. The constant-speed rotational power is input to the constant-speed input shaft 220.
A threshing output pulley 203 is attached to the threshing output shaft 221 (the other end portion of the single shaft), and the threshing output belt 204 wound around the threshing output pulley 203 is passed to the threshing portion 4. Constant speed rotational power from the engine 21 is transmitted.

  In the present embodiment, the threshing clutch mechanism 50 engages or disengages power transmission from the engine 21 to the constant speed input shaft 220 by applying / releasing tension to the constant speed input belt 202. It is comprised so that it can interrupt | block.

As shown in FIG. 11, the constant speed transmission shaft 223 is arranged in the vehicle width direction so that one end is operatively connected to the constant speed input shaft 220 and the other end projects outward from the counter case 210. Along the counter case 210.
The other end of the constant speed transmission shaft 220 forms a swing sorting output shaft 228 that outputs a constant speed rotational power toward the swing sorting section.
A swing output pulley 205 is attached to the swing sorting output shaft 228 (the other end of the constant speed transmission shaft 223).

The vehicle speed tuning input shaft 224 is supported by the counter case 210 along the vehicle width direction with one end portion protruding outward from the counter case 210.
A vehicle speed tuning input pulley 206 is attached to the one end of the vehicle speed tuning input shaft 224.
The speed change transmission shaft 225 is supported by the counter case 210 so as to be substantially parallel to the constant speed transmission shaft 223 and the vehicle speed tuning input shaft 224.

As shown in FIG. 11, the cutting transmission mechanism includes a vehicle speed synchronized transmission mechanism 240 and a constant speed transmission mechanism 250.
The vehicle speed synchronized transmission mechanism 240 is configured to selectively switch the transmission state from the vehicle speed synchronization input shaft 224 to the transmission transmission shaft 225 to a high-speed transmission state, a low-speed transmission state, or a power cut-off state.

Specifically, as shown in FIGS. 11 and 13, the vehicle speed synchronized transmission mechanism 240 includes a high speed gear train 241 and a low speed gear train 242 operatively connected to the vehicle speed synchronized input shaft 224, and the high speed gear train 241 or the A vehicle speed tuning shifter 243 capable of operatively connecting one of the constant speed gear trains 242 to the speed change transmission shaft 225 is provided.
In the present embodiment, the high speed gear train 241 and the low speed gear train 242 are not rotatable relative to the vehicle speed tuning input shaft 224 via a one-way clutch 245.

  The vehicle speed tuning shifter 243 includes a high speed position where the high speed gear train 241 is operatively connected to the speed change transmission shaft 225, a low speed position where the low speed gear train 242 is operatively connected to the speed change transmission shaft 225, and the high speed gear train. 241 and the low-speed gear train 242 can be in a neutral position where the transmission transmission shaft 225 is not operatively connected.

  The constant speed transmission mechanism 250 is configured to selectively flow the transmission state from the constant speed transmission shaft 223 to the transmission transmission shaft 225 to a transmission state, a high-speed cut transmission state, or a power cut-off state.

  Specifically, as shown in FIG. 11, the constant speed transmission mechanism 250 includes a casting gear train 251 and a high speed cutting gear train 252 operatively connected to the constant speed transmission shaft 223, and the casting gear train 251 or A constant speed shifter 253 capable of operatively connecting any one of the high speed cutting gear trains 252 to the speed change transmission shaft 225;

  The constant speed shifter 253 includes a pouring position where the casting gear train 251 is operatively connected to the speed change transmission shaft 225, a high speed cutting position where the high speed cutting gear train 252 is operatively connected to the speed change transmission shaft 225, Both the casting gear train 251 and the high speed cutting gear train 252 can be in a neutral position where the transmission transmission shaft 225 is not operatively connected.

The harvesting output shaft 226 is supported by the counter case 210 with one end portion extending outward.
A cutting output pulley 207 is attached to the one end of the cutting output shaft 226.
In the present embodiment, the cutting output shaft 226 is operatively connected to the speed change transmission shaft 225 via a torque limiter 229.

The FC transmission mechanism 280 is a planetary gear mechanism as shown in FIG.
Specifically, the FC speed change mechanism 280 supports a sun gear 281, a planetary gear 282 meshed with the sun gear 281 so as to revolve around the sun gear 281, and the planetary gear 282 so as to be relatively rotatable. A carrier 283 that revolves around the sun gear 281 together with the planetary gear 282 and an internal gear 284 that meshes with the planetary gear 282 are provided, and rotational power of the constant speed transmission shaft 223 is input to the sun gear 281. The rotational power of the transmission shaft 225 is input to the internal gear 284, and the carrier 283 is operatively connected to the feed chain output shaft 227.
In the present embodiment, an FC clutch mechanism 285 is interposed between the carrier 283 and the feed chain output shaft 227.

As shown in FIG. 10 and FIG. 16 described later, the threshing hydraulic mechanism 230 includes a cylinder 233, a piston 234 accommodated in the cylinder 233 so as to be slidable in the axial direction, and supply / discharge of hydraulic oil to / from the cylinder 233. And a threshing side switching valve 500c for controlling.
The piston 234 includes a head portion 235 that is axially slidable and liquid-tightly accommodated in the cylinder 233, and a rod portion 236 that extends from the head portion 235 to one axial direction.
The cylinder 233 has a first oil chamber 231 and a second oil chamber 232 defined on one side and the other side in the axial direction with the head portion 235 interposed therebetween.

In the present embodiment, the cylinder 233 is formed in the oil passage block 215.
Specifically, the oil passage block 215 has an oil passage plate 215a that is detachably connected to the counter case 210 so as to close the upper opening of the counter case 210.
As shown in FIG. 12, the oil passage plate 215 a has an inner region facing the inner space of the counter case 210 and an outer region extending outward from the counter case 210.
Further, the oil passage block 215 is positioned outside the counter case with a first cylinder block 215b mounted on the lower surface of the inner region of the oil passage plate 215a so as to face the counter case. A second cylinder block 215d mounted on the outer region of the oil passage plate 215a, and a first valve block 215c and a second valve mounted on the oil passage plate 215a so as to be located on the outer side of the counter case 210. And a block 215e.
In such a configuration, the cylinder 233 of the threshing hydraulic mechanism 230 is formed in the second cylinder block 215d.

  The threshing hydraulic mechanism 230 controls the supply and discharge of hydraulic oil to and from the first and second oil chambers 231 and 232 so that the piston 234 moves back and forth in the axial direction. The threshing clutch mechanism 50 that is operatively connected via an appropriate mechanical link mechanism is configured to be removed.

As shown in FIGS. 10, 12, and 13, the mowing hydraulic mechanism includes a vehicle speed tuning side hydraulic mechanism 260 a for operating the vehicle speed tuning transmission mechanism 240 and a constant speed transmission mechanism 250. And a constant speed hydraulic mechanism 260b.
The vehicle speed tuning side hydraulic mechanism 260a and the constant speed side hydraulic mechanism 260b have substantially the same configuration.
Accordingly, in the drawing, the constant speed side hydraulic mechanism 260b is denoted by the reference numeral in which the end of the reference numeral in the vehicle speed tuning side hydraulic mechanism 260a is changed to “b”, and detailed description thereof is omitted.

As shown in FIG. 13, the vehicle speed tuning side hydraulic mechanism 260a controls the supply and discharge of hydraulic oil to and from the cylinder 263a, a double structure piston accommodated in the cylinder 263a so as to be slidable in the axial direction. And a vehicle speed tuning side switching valve 500a.
The piston has a piston body 265a and a ring piston 270a which are separated from each other.
The piston main body 265a includes a head portion 266a, a rod portion 267a extending from the head portion 266a to one side in the axial direction with a step so as to have a smaller diameter than the head portion 266a, and a smaller diameter than the head portion 266a. Thus, a back pressure rod portion 268a extending from the head portion 266a to the other side in the axial direction with a step is provided.
The ring piston 270a has a ring shape larger in diameter than the head portion 266a, and is axially movable relative to the back pressure rod 268a and is extrapolated in a liquid-tight manner.

The cylinder 263a includes a large-diameter space in which the ring piston 270a is axially slidable and liquid-tightly accommodated, and a small-diameter space that extends to one side in the axial direction with a step so as to be smaller in diameter than the large-diameter space. The head portion 266a has a small-diameter space in which the head portion 266a can slide in the axial direction and is liquid-tightly accommodated.
In the cylinder 263a, a portion of the small-diameter space located on one side in the axial direction from the head portion 266a is a first oil chamber 261a, and the large-diameter space is on the other side in the axial direction from the ring piston 270a. The part located in is made the second oil chamber 262a.
In the present embodiment, as shown in FIGS. 12 and 13, the cylinders 263 a and 263 b are formed in the oil passage block 215, specifically, the first cylinder block 215 b facing the internal space of the counter case 210. ing.

The vehicle speed tuning side hydraulic mechanism 260a having such a configuration operates as follows.
That is, when hydraulic oil is supplied to the first oil chamber 261a and the second oil chamber 262a is drained, the piston body 265a pushes the ring piston 270a by the pressure oil in the first oil chamber 261a. However, the second oil chamber 262a is moved in the direction of contraction. The piston moves the vehicle speed tuning shifter 243 linked to the piston rod 267a to one of the high speed position and the low speed position (high speed position in the illustrated embodiment) by the hydraulic pressure of the first oil chamber 261a. The first operating state is maintained.

  On the contrary, when the first oil chamber 261a is drained and the hydraulic oil is supplied to the second oil chamber 262a, the piston main body 265a is moved to the first oil by the pressure oil in the second oil chamber 262a. The chamber 261a is moved in the direction of reducing. The piston moves the vehicle speed tuning shifter 243 linked to the piston rod 267a to the other of the high speed position and the low speed position (low speed position in the illustrated embodiment) by the hydraulic pressure of the second oil chamber 262a. The second operating state is maintained.

Further, when hydraulic oil is supplied to both the first oil chamber 261a and the second oil chamber 262a, the ring piston 270a is moved between the large diameter space and the small diameter space by the pressure oil in the second oil chamber 262a. The piston main body 265a is pushed to a position where the head portion 266a abuts against the ring piston 270a by the pressure oil in the first oil chamber 261a.
That is, in a state where hydraulic oil is supplied to both the first and second oil chambers 261a and 261b, the piston is applied to the piston rod 267a by the hydraulic pressure of the first and second oil chambers 261a and 261b. The linked vehicle speed tuning shifter 243 is held in an intermediate state in which it is positioned at the neutral position.
As shown in FIGS. 12 and 13, the oil passage block 215 has one end opened into the cylinder 263 a at a position straddling the step between the large diameter space and the small diameter space, and the other end. An open oil passage 514a having a portion opened to the atmosphere is formed, and the open oil passage 514a allows movement of only the other without moving one of the piston body 265a and the ring piston 270a. .

  Similarly to the vehicle speed tuning side hydraulic mechanism 260a, the constant speed side hydraulic mechanism 260b controls the supply and discharge of hydraulic oil to and from the first oil chamber 261b and the second oil chamber 262b, so that the piston main body 265b moves back and forth in the axial direction. Accordingly, the constant speed shifter 253 operatively connected to the piston rod 265b via an appropriate mechanical link mechanism is selectively positioned at the pouring position, the high speed cutting position, or the neutral position. (See FIG. 16 described later).

Here, the hydraulic circuit of the combine 1 will be described.
FIG. 14 shows a schematic hydraulic circuit diagram of the combine.
As shown in FIGS. 10 and 14, the combine 1 includes a threshing / cutting operation switching circuit for supplying and discharging hydraulic oil to / from the threshing hydraulic mechanism 230 and the chopping hydraulic mechanisms 260 a and 260 b, and the chopping lifting hydraulic pressure. A work machine drive circuit that controls supply and discharge of hydraulic fluid to and from other hydraulic mechanisms including the mechanism 11 and a travel system circuit that controls hydraulic control of the travel system hydraulic mechanism including the travel HST and the turning HST are provided.

As shown in FIGS. 10 and 14, the work machine drive circuit is configured so that the left and right sides and the other side of the machine frame 3 are connected to the traveling unit 2 in addition to the hydraulic oil supply / discharge of the cutting lift hydraulic mechanism 11. The first hydraulic mechanism 60a for raising and lowering the vehicle body, the second hydraulic mechanism 60b for raising and lowering the vehicle body, and the raising and lowering of the discharge auger 17 (see FIGS. 1 and 2). It is also configured to control and supply hydraulic oil to and from the hydraulic mechanism 65.
The detailed configuration of the work machine drive circuit and the detailed configuration of the threshing / reaping operation switching circuit will be described later.

As shown in FIG. 10, the traveling system circuit includes a pair of traveling hydraulic oil lines 400 that fluidly connect the traveling hydraulic pump main body 122 and the traveling hydraulic motor main body 123 so as to form a closed circuit. The swing hydraulic pump main body 132 and the swing hydraulic motor main body 133 are fluidly connected to each other so as to form a closed circuit, and a pair of swing hydraulic oil lines 410 and the pair of travel hydraulic oil lines 400 are respectively connected. And a charge line 420 for supplying hydraulic oil to each of the pair of turning hydraulic oil lines 410, the charge line 420 adjusted to a predetermined pressure by a charge pressure setting relief valve 425, and the travel line A traveling hydraulic servo circuit 430 for supplying and discharging hydraulic oil to and from the hydraulic servo mechanism 35 and the turning hydraulic servo mechanism 45 And a swing hydraulic servo mechanism 440 which controls the hydraulic oil supply and discharge.
The traveling hydraulic servo mechanism 35 and the turning hydraulic servo mechanism 45 are configured to operate using the pressure oil in the charge line 420.

  As shown in FIGS. 10 and 14, the combine 1 according to the present embodiment includes a charge pump 810 and an auxiliary pump 820 in addition to the above configuration, and the threshing / reaping operation switching circuit and the work machine drive Pressure oil is supplied from the auxiliary pump 820 to the circuit, and pressure oil is supplied from the charge pump 810 to the charge line 420.

  10 and 14, the charge pump 810 is configured to operate using oil stored in the mission case 110 as an oil source, and the auxiliary pump 820 is stored in the counter case 210. It is configured to operate using oil as an oil source, whereby the transmission efficiency of the traveling transmission mechanism housed in the mission case 110 is caused by the stirring resistance caused by the stored oil in the mission case 110. It effectively prevents the deterioration.

  That is, pressure oil from a single charge pump that uses oil stored in the mission case 110 as an oil source is added to the charge line 420 and also supplied to the threshing / reaping operation switching circuit and the work machine drive circuit. In addition to the amount of oil necessary for the charge oil of the HSTs 120 and 130 in the mission case 110, the conventional configuration that is configured as described above is necessary as hydraulic fluid for the threshing hydraulic mechanism and the reaping hydraulic mechanism. There is a problem that the amount of oil must be stored, and the transmission efficiency of the traveling transmission mechanism housed in the transmission case 110 is deteriorated due to the stirring resistance caused by the stored oil.

On the other hand, in the combine 1 according to the present embodiment, the auxiliary pump 820 that supplies hydraulic oil to the threshing / reaping operation switching circuit and the work machine drive circuit, and the charge line 420 are pressurized. The charge pump 810 for supplying oil, and the auxiliary pump 820 uses the oil stored in the counter case 210 as an oil source, and the charge pump 810 uses the oil stored in the mission case 110 as an oil source. ing.
Accordingly, it is possible to reduce the amount of oil stored in the transmission case 110, thereby effectively preventing the transmission efficiency of the traveling transmission mechanism from deteriorating due to the oil stored in the transmission case 110. it can.

Thus, in the present embodiment, the amount of stored oil in the mission case 110 is reduced as much as possible.
In such a configuration, preferably, an oil extraction port 115 from the mission case 110 to the charge pump 810 can be provided at the lowermost part of the mission case 110 (see FIG. 15). It is possible to effectively prevent the oil shortage phenomenon from occurring in 420.

The charge pump 810 is directly or indirectly supported by the mission case 110 so that it can be driven to rotate by the turning pump shaft 131, for example.
The auxiliary pump 820 is directly or indirectly supported by the engine 21 so that the auxiliary pump 820 can be rotationally driven by the engine 21.

Here, a detailed configuration of the threshing / reaping operation switching circuit will be described.
FIG. 16 shows a hydraulic circuit diagram of the threshing / reaping operation switching circuit.
As described above, the counter case 210 is open at the top, and the opening is closed by the oil passage block 215.

As shown in FIGS. 12, 13 and 16, the oil passage block 215 includes the vehicle speed tuning side switching valve 500a for switching between supply and discharge of hydraulic fluid to the vehicle speed tuning side hydraulic mechanism 260a and the constant speed side hydraulic pressure. A constant speed side switching valve 500b for switching the supply and discharge of hydraulic oil to and from the mechanism 260b and the threshing side switching valve 500c for switching the supply and discharge of hydraulic oil to and from the threshing hydraulic mechanism 230 are mounted.
Specifically, the vehicle speed tuning side switching valve 500a and the constant speed side switching valve 500b are mounted on the first valve block 215c, and the threshing side switching valve 500c is mounted on the second valve block 215e ( (See FIG. 12).

Further, as shown in FIGS. 12 and 13, the oil passage block 215 includes the vehicle speed tuning side hydraulic mechanism 260 a and the constant speed side hydraulic mechanism 260 b in a portion of the lower surface facing the internal space of the counter case 210. The threshing hydraulic mechanism 230 is supported at a portion of the lower surface that is positioned outside the counter case 210.
Specifically, the vehicle speed tuning side hydraulic mechanism 260a and the constant speed side hydraulic mechanism 260b are supported by the first cylinder block 215b, and the threshing hydraulic mechanism 230 is supported by the second cylinder block 215e ( (See FIG. 12).

  Further, as shown in FIG. 16, the oil passage block 215 includes a supply oil passage 510 having one end portion opened to the outer surface and forming a pump port 510P, and one end portion of the oil passage block 215 in the vehicle speed tuning side hydraulic mechanism 260a. A vehicle speed tuning side first hydraulic oil passage 511a fluidly connected to the first oil chamber 261a and the other end fluidly connected to the vehicle speed tuning side switching valve 500a, and one end of the first oil chamber 261a in the vehicle speed tuning side hydraulic mechanism 260a. A second hydraulic fluid passage 512a that is fluidly connected to the two oil chamber 262a and the other end of which is fluidly connected to the vehicle speed tuning side switching valve 500a, and one end of which is fluidly connected to the vehicle speed tuning side switching valve 500a. The vehicle speed tuning side drain oil passage 513a and one end thereof are fluidly connected to the first oil chamber 261b in the constant speed hydraulic mechanism 260b and the other end is connected to the constant speed switching valve 500b. The body-connected constant speed side first hydraulic fluid passage 511b, one end portion of which is fluidly connected to the second oil chamber 262b of the constant speed side hydraulic mechanism 260b, and the other end portion of which is fluidly connected to the constant speed side switching valve 500b. The connected constant speed side second hydraulic oil passage 512b, the constant speed side drain oil passage 513b whose one end is fluidly connected to the constant speed switching valve 500b, and one end thereof in the hydraulic mechanism 230 for threshing. A threshing-side first hydraulic oil passage 511c fluid-connected to one oil chamber 231 and the other end fluidly connected to the threshing-side switching valve 500c, and the second oil chamber 232 in the threshing hydraulic mechanism 230 having one end portion. And a threshing side drain oil passage 513c whose other end is fluidly connected to the threshing side switching valve 500c, and a threshing side drain oil passage 513c whose one end is fluidly connected to the threshing side switching valve 500c. And formed It has been.

  As shown in FIG. 16, the vehicle speed tuning side switching valve 500a includes a neutral position N for fluidly connecting the supply oil passage 510 to both the vehicle speed tuning side first and second hydraulic oil passages 512a, b, and the supply. A high speed position H for fluidly connecting the oil passage 510 to the vehicle speed tuning side first hydraulic fluid passage 511a and fluidly connecting the vehicle speed tuning side second hydraulic fluid passage 512a to the vehicle speed tuning side drain oil passage 513a; A low speed position L can be taken to fluidly connect the path 510 to the vehicle speed tuning side second hydraulic oil path 512a and to fluidly connect the vehicle speed tuning side first hydraulic oil path 511a to the vehicle speed tuning side drain oil path 513a. It is configured.

  As shown in FIG. 16, the constant speed side switching valve 500b includes a neutral position N that fluidly connects the supply oil passage 510 to both the first and second hydraulic oil passages 511b, b, and the supply A pouring position L for fluidly connecting the oil passage 510 to the first constant speed side hydraulic fluid passage 511b and fluidly connecting the constant speed side second hydraulic fluid passage 512b to the constant speed side drain oil passage 513c; A high-speed cut position H can be taken which fluidly connects the path 510 to the constant speed side second hydraulic oil path 512b and fluidly connects the constant speed side first hydraulic oil path 511b to the constant speed side drain oil path 513c. It is configured.

  As shown in FIG. 16, the threshing side switching valve 500c fluidly connects the supply oil passage 510 to the threshing side first hydraulic oil passage 511c and connects the threshing side second hydraulic oil passage 512c to the threshing side drain oil. A blocking position OFF for fluidly connecting to the passage 513c, fluid connection of the supply oil passage 510 to the second threshing-side second hydraulic oil passage 512c, and fluidization of the threshing-side first hydraulic oil passage 511c to the threshing-side drain oil passage 513c. It is configured to be able to take the engagement position ON to be connected.

In the present embodiment, as shown in FIG. 16, the other end of the vehicle speed tuning side drain oil passage 513a, the constant speed side drain oil passage 513b, and the threshing side drain oil passage 513c functions as an oil sump. The counter case 210 can be fluidly connected to the internal space.
As described above, in the present embodiment, the oil discharged from the vehicle speed tuning side hydraulic mechanism 260a, the low speed side hydraulic mechanism 260b, and the threshing hydraulic mechanism 230 is discharged into the counter case 210. As a result, the drain piping structure can be simplified compared to the conventional configuration in which the oil discharged from each hydraulic mechanism is returned to the transmission case in the traveling transmission via the external piping. Yes.
Furthermore, in the present embodiment, as described above, the vehicle speed tuning side hydraulic mechanism 260a, the low speed side hydraulic mechanism 260b, and the threshing hydraulic mechanism 230 use the auxiliary oil using the oil stored in the counter case 210 as an oil source. It is configured to operate by pressure oil from the pump 820. Therefore, the hydraulic oil of each hydraulic mechanism is circulated in the counter case 210, thereby simplifying the supply / discharge oil passage of each hydraulic mechanism.

In the present embodiment, as shown in FIGS. 13 and 16, the vehicle speed tuning side drain oil passage 513a uses the open oil passage 514a to discharge oil from the vehicle speed tuning side hydraulic mechanism 260a. Is discharged into the counter case 210.
Specifically, as shown in FIGS. 13 and 16, the vehicle speed tuning side drain oil passage 513a has one end fluidly connected to the vehicle speed tuning side switching valve 500a and the other end connected to the large-diameter space and the The cylinder 263a is opened at a position across the step between the small diameter spaces.

Similarly, the constant speed side drain oil passage 513b uses the open oil passage 514b to discharge the oil discharged from the constant speed side hydraulic mechanism 260b into the counter case 210 as shown in FIG. It is configured as follows.
Specifically, as shown in FIG. 16, the constant speed side drain oil passage 513b has one end fluidly connected to the constant speed side switching valve 500b and the other end connected to the large diameter space and the small diameter space. The cylinder 263b is opened at a position across the step.

With such a configuration, the oil discharged from the first oil chamber 261a or the second oil chamber 262a in the vehicle speed tuning side hydraulic mechanism 260a is supplied to the piston main body 265a and the piston in the vehicle speed tuning side hydraulic mechanism 260a. It can be returned to the counter case 210 acting as an oil reservoir while being used as lubricating oil for both of the ring pistons 270a.
The constant speed hydraulic mechanism 260b operates in substantially the same manner as the vehicle speed tuning hydraulic mechanism 260a. Therefore, the description of the constant speed hydraulic mechanism 260b is omitted.

  That is, as described above, when the vehicle speed tuning side switching valve 500a is located at the neutral position N, the ring piston 270a abuts against the step by the pressure oil in the second oil chamber 262a and the first oil chamber. The piston main body 265a is in contact with the ring piston 270a by the pressure oil of 261a. In this state, the vehicle speed tuning side drain oil passage 513a is closed by the ring piston 270a and the head portion 266a of the piston body 265a (see FIG. 13).

On the other hand, when the vehicle speed tuning side switching valve 500a is positioned at the high speed position H, the first oil chamber 261a receives pressure oil from the supply oil path 510 via the vehicle speed tuning side first hydraulic oil path 511a and The second oil chamber 262a is fluidly connected to the vehicle speed tuning side discharge oil path 513a via the vehicle speed tuning side second hydraulic oil path 512a.
In this state, the piston main body 265a moves in a direction to reduce the second oil chamber 262a while pushing the ring piston 270a, whereby the vehicle speed tuning side drain oil passage 513a is connected to the cylinder 263a. The open oil passage 514a communicates with a large-diameter space and a gap between the head portion 266a.
In other words, when the vehicle speed tuning side switching valve 500a is positioned at the high speed position H, the second oil chamber 262a includes the vehicle speed tuning side second hydraulic oil path 512a, the vehicle speed tuning side drain oil path 513a, and the cylinder. It is fluidly connected to the internal space of the counter case 210 through the large-diameter space of 263a and the gap between the head portion 266a and the open oil passage 514a.
At this time, the oil flowing from the vehicle speed tuning side drain oil passage 513a to the open oil passage 514a effectively acts as lubricating oil for the head portion 266a.

When the vehicle speed tuning side switching valve 500a is positioned at the low speed position L, the second oil chamber 262a receives pressure oil from the supply oil path 510 via the vehicle speed tuning side second hydraulic oil path 512a and The first oil chamber 261a is fluidly connected to the vehicle speed tuning side discharge oil path 513a via the vehicle speed tuning side first hydraulic oil path 511a.
In this state, the piston main body 265a moves in a direction to reduce the first oil chamber 261a, whereby the vehicle speed tuning side drain oil passage 513a is connected to the small-diameter space of the cylinder 263a and the back pressure rod portion 268a. Is communicated with the open oil passage 514a through a gap therebetween.
In other words, when the vehicle speed tuning side switching valve 500a is located at the low speed position L, the first oil chamber 261a includes the vehicle speed tuning side first hydraulic oil path 511a, the vehicle speed tuning side discharge oil path 513a, and the cylinder. It is fluidly connected to the internal space of the counter case 210 via the gap between the small diameter space of 263a and the back pressure rod portion 268a, and the open oil passage 514a.
At this time, the oil flowing from the vehicle speed tuning side drain oil passage 513a to the open oil passage 514a effectively acts as lubricating oil for the back pressure rod portion 268a.

The threshing drain oil passage 513c is also configured to discharge drain oil into the counter case 210, similarly to the vehicle speed tuning side drain oil passage 513a and the constant speed side drain oil passage 513b.
In the present embodiment, as shown in FIG. 16, the threshing drain oil passage 513c is fluidly connected to the vehicle speed tuning side drain oil passage 513a and the constant speed side drain oil passage 513b at the other end. The oil discharged from the threshing hydraulic mechanism 230 is discharged into the counter case 210 through the vehicle speed tuning side drain oil passage 513a and the constant speed side drain oil passage 513b.

Preferably, an opening end portion of the vehicle speed tuning side drain oil passage 513a and / or the constant speed side drain oil passage 513b into the counter case 210 can be directed to the cutting transmission mechanism.
By providing such a configuration, oil flowing into the counter case 210 via the vehicle speed tuning side drain oil passage 513a and / or the constant speed side drain oil passage 513b is allowed to flow into the vehicle speed tuning transmission mechanism 240 and the constant speed. It can also be used as lubricating oil for the transmission mechanism 250.
In the present embodiment, as described above, the vehicle speed tuning side drain oil passage 513a is opened in the counter case 210 through the open oil passage 514a. The constant speed side drain oil passage 513b is opened in the counter case 210 through the open oil passage 514b. Accordingly, the open end of the open oil passage 514a (and / or 514b) to the counter case 210 is opened toward the cutting transmission mechanism (see FIG. 12).

Preferably, the one end portion of the open oil passage 514a (514b) is opposed to the other end portion of the drain oil passage 513a (513b) across the piston, and the cylinder 261a (261b) Opened to the inner peripheral surface.
That is, the open end of the open oil passage 514a (514b) to the cylinder and the open end of the drain oil passage 513a (513b) to the cylinder are spaced 180 degrees in the circumferential direction with respect to the axis of the cylinder. The oil flowing from the drain oil passage 513a (513b) to the open oil passage 514a (514b) can be efficiently brought into contact with the piston.

Next, a detailed configuration of the work machine drive circuit will be described.
FIG. 17 shows a hydraulic circuit diagram of the work machine drive circuit.
As shown in FIG. 17, in the present embodiment, the work machine drive circuit includes a cutting lift hydraulic circuit 600 that supplies and discharges hydraulic oil to and from the cutting lift hydraulic mechanism 11, and the first vehicle lifting first. A first hydraulic circuit for raising and lowering the vehicle body 550a for supplying and discharging hydraulic oil to and from the hydraulic mechanism 60a, a second hydraulic circuit for raising and lowering the vehicle body for supplying and discharging hydraulic oil to and from the second hydraulic mechanism for raising and lowering the vehicle body 60b, and the discharge And a discharge auger lifting / lowering hydraulic circuit 570 for supplying / discharging hydraulic oil to / from the auger lifting / lowering hydraulic mechanism 65.

The mowing raising / lowering hydraulic circuit 600 selectively supplies the hydraulic oil from the auxiliary pump 820 acting as a hydraulic pressure source to the mowing raising / lowering hydraulic mechanism 11 acting as a hydraulic actuator, and the supply line 601 selectively. And a direction switching valve 610 that communicates with or shuts off.
The detailed configuration of the cutting lift hydraulic circuit 600 will be described later.

The first hydraulic circuit 550a for raising and lowering the vehicle body includes a supply line 551a fluidly connected to the auxiliary pump 820 having one end acting as a hydraulic pressure source, and an oil sump (in the present embodiment, the internal space of the counter case 210). A drain line 552a fluidly connected to the vehicle body, a supply / discharge line 553a fluidly connected to the first hydraulic mechanism 60a for raising and lowering the vehicle body, and a direction of switching the supply line 551a and the drain line 552a with respect to the supply / discharge line 553a. And a switching valve 555a.
The second lifting / lowering hydraulic circuit 550b has the same configuration as the first lifting / lowering hydraulic circuit 550a. Therefore, the second hydraulic circuit for raising / lowering the vehicle body 550b is denoted by a reference numeral in the drawing in which the end of the reference numeral in the first hydraulic circuit for raising / lowering the vehicle body 550a is replaced with “b”, and detailed description thereof is omitted. .

  The discharge auger lifting / lowering hydraulic circuit 570 includes a supply line 571 fluidly connected to the auxiliary pump 820 having one end acting as a hydraulic pressure source, and an oil sump (in the present embodiment, the internal space of the counter case 210). A fluid-connected drain line 572, a supply / discharge line 573 fluidly connected to the discharge auger lifting / lowering hydraulic mechanism 65, and a direction switching valve that switches the supply line 571 and the drain line 572 to the supply / discharge line 573. 575.

  In the present embodiment, the mowing raising / lowering hydraulic circuit 600, the vehicle body raising / lowering first hydraulic circuit 550a, the vehicle body raising / lowering second hydraulic circuit 550b, and the discharge auger raising / lowering hydraulic circuit 570 are configured as a single unit. It is formed in a working machine oil passage block 700.

Here, the detailed configuration of the hydraulic circuit for lifting and lowering will be described.
As shown in FIG. 16, the cutting lift hydraulic circuit 600 includes a drain line 602 communicated with the supply line 601 between the direction switching valve 610 and the cutting lift hydraulic mechanism 11 in addition to the above-described configuration. A pilot pressure actuated variable throttle valve 611 inserted in the drain line 602, a pilot line 603 for applying pilot pressure to the variable throttle valve 611, and pressure oil supply to the pilot line 603. An electromagnetic proportional pressure reducing valve 612 to be adjusted, and the position control of the variable throttle valve 611 is performed by adjusting the pressure oil supply to the pilot line 603 by the electromagnetic proportional pressure reducing valve 612, and the cutting lift hydraulic pressure The operation speed of the mechanism 11 can be controlled.
According to such a configuration, the electromagnetic proportional pressure reducing valve 612 is not inserted in the oil supply / discharge oil passage 601 of the hydraulic actuator, so that the electromagnetic proportional pressure reducing valve 612 does not increase in size, and the cutting lifting and lowering hydraulic mechanism is increased. 11 operating speeds can be controlled within a sufficient range.

  Further, in the present embodiment, pressure oil is supplied from the charge line 420 for supplying hydraulic oil to the traveling HST 120 and the turning HST 130 to the pilot line 603 via the electromagnetic proportional pressure reducing valve 612. As a result, the load on the auxiliary pump 820 is reduced, and the flow rate adjustment valve 695 and the pilot line relief valve 696 (see FIG. 18), which are conventionally required, are unnecessary. We are trying to make it.

That is, as shown in FIG. 18, the conventional mowing lifting / lowering hydraulic circuit is configured such that a part of the pressure oil in the supply line 601 is taken out and supplied to the primary side of the electromagnetic proportional pressure reducing valve 612. Regardless of whether or not the variable throttle valve 611 is operated, there is a problem that a load is always applied to the auxiliary pump 820.
That is, in the conventional hydraulic structure, as shown in FIG. 18, a part of the pressure oil in the supply line 601 is branched to the pilot pressure extraction line 690 via the flow rate adjusting valve 695, and the pilot extraction line 690 is branched. Is supplied to the primary side of the electromagnetic proportional pressure reducing valve 612 in a state in which the pressure oil is regulated by the relief valve 696.
In such a configuration, even when the variable throttle valve 611 is not operated, a constant amount of pressure oil always flows through the pilot pressure extraction line 690, and an unnecessary load is applied to the auxiliary pump 820. It always takes.
Further, in the conventional configuration, the flow rate adjusting valve 695 for taking out the pressure oil to the pilot pressure take-out line 690 and the relief valve 696 for setting the oil pressure of the pilot pressure take-out line 690 are necessary. There is also a problem that the cost increases and the size increases due to an increase in the number of points.

On the other hand, in the present embodiment, as described above, the hydraulic oil in the pilot line 603 is taken out from the charge line 420 adjusted to a predetermined pressure by the charge pressure setting relief valve 425. (See FIG. 10 etc.).
Therefore, the load on the auxiliary pump 820 can be reduced, and the flow rate adjusting valve 695 and the relief valve 696 for the pilot line can be eliminated.
It should be noted that the charge pump 810 is constantly supplied with a sufficient amount of pressure oil to sufficiently supply hydraulic oil to the traveling HST 120 and the turning HST 130 to the charge line 420, and surplus oil is set to the charge pressure setting. The relief valve 425 is used for relief into the mission case 110.
Therefore, even if the hydraulic fluid for the pilot line 603 is taken out from the charge line 420, the load on the charge pump 810 does not increase so much.
Preferably, the relief oil of the charge pressure setting relief valve 425 flows into the transmission case 110 at a position where the transmission mechanism accommodated in the transmission case 110 can be lubricated.

Preferably, the oil may overflow from the counter case 210 to the mission case 110 when the amount of oil stored in the counter case 210 exceeds a predetermined amount.
That is, in the present embodiment, the traveling system drive circuit forms a closed circuit including the internal space of the mission case 110, and the threshing / reaping operation switching circuit and the work implement drive circuit are the counter. A closed circuit including the case is formed.
Accordingly, when a part of the pressure oil from the charge pump 810 using the stored oil in the mission case 110 as an oil source is caused to flow to the pilot line 603, the entire closed circuit formed by the traveling system circuit is formed. While the oil amount gradually decreases, the total oil amount in the closed circuit formed by the threshing / reaping operation switching circuit and the work implement drive circuit gradually increases.
In view of this point, preferably, the counter case 210 and the mission case 110 can be fluidly connected by a communication line 490 such as an external pipe (see FIG. 14).
According to such a configuration, the amount of stored oil in the counter case 210 and the amount of stored oil in the mission case can be maintained substantially constant.
As described above, the counter case 210 is supported on the machine frame 3, while the mission case 110 is arranged so as to be positioned above and below the machine frame 3 (see FIG. 4 and FIG. 6).
Therefore, the fluid stored in the counter case 210 and the mission case 110 can be fluidly connected to the mission case 110 from the counter case 210 (by gravity) by fluid connection with an external pipe.

  Reference numeral 620P in FIGS. 10 and 17, etc., is a pump port provided in the working machine oil passage block 700 for fluidly connecting the supply line 601 to the auxiliary pump 820, and reference numeral 620T is the work port. A tank port provided in the oil passage block 700 for the working machine in order to discharge drain oil from the machine drive circuit to the oil sump (the counter case 210 in the present embodiment), and reference numeral 620Pa denotes the charge line A pilot port provided in the working machine oil passage block 700 for receiving the hydraulic oil for the pilot line 603 from 420.

  In the present embodiment, the cutting lift hydraulic circuit 600 further includes a main relief valve 615 that sets the hydraulic pressure of the supply line 601, and one end portion between the direction switching valve 610 and the cutting lift mechanism 11. The bypass line 605 is fluidly connected to the supply line 601 and the other end is fluidly connected to an oil sump, and includes a bypass line 605 in which a manually operable on-off valve 618 is inserted.

In the present embodiment, hydraulic fluid is supplied from the supply line 601 to the supply lines 551a, 551b, and 571 via the direction switching valve 610.
Specifically, the working machine oil passage block 700 is formed with a discharge line 606 having one end fluidly connected to the drain line 602 and the other end fluidly connected to the direction switching valve 610.
Then, the direction switching valve 610 includes a cutting lift hydraulic mechanism operating position for supplying the pressure oil in the supply line 601 only to the cutting lift hydraulic mechanism 11, and the supply of the pressure oil in the supply line 601. Another hydraulic mechanism operating position for supplying to the lines 551a, 551b, and 571 and a hydraulic mechanism non-operating position for supplying the pressure oil in the supply line 601 to the discharge line 606 can be taken.
The oil in the drain lines 602, 552a, 552b, and 572 and the discharge line 606 is concentrated in a single tank line 607, and the tank line 607 is fluidly connected to the oil sump via the tank port 620T. Yes.

FIG. 1 is a perspective view of a combine to which an embodiment of the present invention is applied. FIG. 2 is a right side view of the combine. FIG. 3 is a schematic diagram of transmission of the combine. FIG. 4 is a front left side view of the machine in the combine. FIG. 5 is a front view of the machine in the combine. FIG. 6 is a partial left side view of the vicinity of the engine, the traveling transmission, and the work implement transmission in the combine. FIG. 7 is a transmission schematic diagram of the traveling transmission. FIG. 8 is a plan view of the traveling transmission. FIG. 9 is a longitudinal rear view of the traveling transmission. FIG. 10 is a hydraulic circuit diagram of the traveling transmission and the work implement transmission. FIG. 11 is a transmission schematic diagram of the work machine transmission. FIG. 12 is a partial longitudinal sectional side view of the work machine transmission. FIG. 13 is a partial longitudinal rear view of the work machine transmission along the line XIII-XIII in FIG. 13. FIG. 14 is a schematic hydraulic circuit diagram of the combine. FIG. 15 is a side view of the traveling transmission. FIG. 16 is a hydraulic circuit diagram of a threshing / reaping operation switching circuit in the combine. FIG. 17 is a hydraulic circuit diagram of a work machine drive circuit in the combine. FIG. 18 is a hydraulic circuit diagram of a conventional work machine drive circuit.

Explanation of symbols

1 Combine 11 Mowing lifting hydraulic mechanism (hydraulic actuator)
21 Engine 110 Mission case 120 Traveling HST (traveling system HST)
130 HST for turning (travel system HST)
210 Countercase 420 Charge line 490 Communication line 601 Supply line 602 Drain line 603 Pilot line 610 Directional switching valve 611 Variable throttle valve 612 Electromagnetic proportional pressure reducing valve 810 Charge pump 820 Auxiliary pump (hydraulic pump)

Claims (2)

A traveling system HST operatively connected to the engine; a charge pump operatively coupled to the engine; a charge line regulated to a predetermined pressure to replenish hydraulic fluid from the charge pump to the traveling system HST; An auxiliary pump operatively connected to the engine, a cutting lift hydraulic mechanism that lifts and lowers the cutting part by pressure oil from the auxiliary pump, a supply line that supplies pressure oil from the auxiliary pump to the cutting lift hydraulic mechanism, A direction switching valve for selectively communicating or shutting off the supply line, a drain line communicating with the supply line between the direction switching valve and the cutting lift hydraulic mechanism, and a pilot inserted in the drain line A pressure-actuated variable throttle valve, a pilot line for applying a pilot pressure to the variable throttle valve, and the pilot line An electromagnetic proportional pressure reducing valve for adjusting the pressure oil supply, and adjusting the position of the variable throttle valve by adjusting the pressure oil supply to the pilot line by the electromagnetic proportional pressure reducing valve; A combine configured to control the operating speed,
A combine configured to supply pressure oil from the charge line to the pilot line via the electromagnetic proportional pressure reducing valve. The charge pump is configured to use oil stored in the mission case as an oil source, and surplus oil in the charge line is returned to the mission case.
The auxiliary pump uses oil stored in the counter case as an oil source, drain oil from the cutting lifting hydraulic mechanism and pressure oil from the charge line that is blocked from being supplied to the pilot line by the electromagnetic proportional pressure reducing valve, It is configured to be returned to the counter case,
The combine according to claim 1, wherein the counter case and the mission case are fluidly connected via a communication line.

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