JP2020125184A - Winch device and crane equipped with the same - Google Patents

Abstract

To provide a winch device capable of preventing the inconvenience of incursion of air in a hydraulic circuit of the winch device, and a crane equipped with the winch device.SOLUTION: A winch device 10 is configured such that an outer pipe 61 of a piston 6 has an outer hole H1 formed through the outer pipe 61 in the thickness direction thereof and communicated with one of positive and negative hydraulic chambers 3a, 3b, and an inner pipe 13 has an inner hole H2 formed through the inner pipe 13 in the thickness direction thereof and communicated with a cooling oil passage 14. The outer hole H1 and the inner hole H2 are set at positions relative to each other such that the outer hole H1 is covered with the outer peripheral surface of the inner pipe 13 when the piston 6 is located within a brake range R1, and at least a part of the outer hole H1 overlaps the inner hole H2 to communicate one of the hydraulic chambers with the cooling oil passage 14 of the inner pipe 13 when the piston 6 is located within a free communication range R22 constituting at least a part of a free range R2.SELECTED DRAWING: Figure 3

Description

The present invention relates to a winch device for winding a rope and a crane including the winch device.

In general, a crane is a self-propelled undercarriage, an upper revolving structure rotatably mounted on the lower revolving structure, a boom mounted on the upper revolving structure so that it can be raised and lowered, and a rope from the tip of the boom or jib. And a winch device having a winch drum for winding the rope.

For example, Patent Literature 1 discloses a winch brake device including a wet multi-plate brake. The winch (winch drum) in Patent Document 1 is provided in the upper swing body. Patent Document 2 discloses a crane in which a winch drum is supported by a boom.

JP, 2016-222380, A JP, 2016-222358, A

By the way, a crane may be disassembled into a plurality of components for various purposes and then reassembled, and accordingly, a part of the piping of the hydraulic circuit is detached from the connecting portion, and then again connected to the connecting portion. Connected. When the piping of the hydraulic circuit is detached from the connecting portion in this manner, air may be mixed in the hydraulic circuit. When air is mixed in the hydraulic circuit, the response of the brake may be reduced in a winch device including a wet brake such as the brake device disclosed in Patent Document 1, for example. Specific examples are as follows.

For example, a member such as a boom may be removed from the upper swing body for the purpose of transporting a crane. However, when the winch drum is supported by the boom, such as the winch drum in Patent Document 2, the pipe of the hydraulic circuit is arranged so as to straddle the upper swing body and the boom, and thus the boom is swung upward. When removed from the body, it is necessary to remove part of the hydraulic circuit tubing from its connection. After the transportation of the crane, the removed member such as the boom is reattached to the upper swing body, and the removed pipe of the hydraulic circuit is reconnected to the connecting portion. When the piping of the hydraulic circuit is detached from the connecting portion in this manner, air may be mixed in the hydraulic circuit.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a winch device capable of avoiding the inconvenience caused by air mixing in a hydraulic circuit in the winch device, and a crane including the winch device.

As a means for achieving the above-mentioned object, the inventors of the present invention have provided a winch device with a positive oil chamber and a negative oil chamber through which hydraulic oil flows, and a cooling oil passage through which cooling oil for cooling the clutch portion flows. Focusing on the relative position, it has been conceived to use the relative position to discharge the air mixed in the hydraulic circuit. Specifically, the cooling oil passage is generally defined by the inner peripheral surface of a tubular piston that moves relative to the cylinder, and each of the positive oil chamber and the negative oil chamber is an outer peripheral surface of the piston and the cylinder. And the inner peripheral surface of the. That is, the positive oil chamber, the negative oil chamber, and the cooling oil passage are provided so as to be adjacent to each other via the tubular portion of the piston. In each of the positive oil chamber and the negative oil chamber, the volume of each oil chamber increases or decreases with the relative movement of the piston with respect to the cylinder, and a relatively small amount of hydraulic oil corresponding to the increase or decrease in the volume of each oil chamber. Goes in and out. When such a relatively small amount of hydraulic oil comes in and out, the air mixed in the pipe of the hydraulic circuit and the oil chamber connected to the pipe cannot be effectively discharged to the outside. On the other hand, in the cooling oil passage, a relatively large amount of cooling oil for cooling the clutch portion flows continuously or intermittently. The inventors have adopted the following air bleeding structure in order to utilize the flow of a relatively large amount of cooling oil in the cooling oil passage for discharging air. Specifically, in the air bleeding structure, a tubular member (inner pipe portion) is further provided inside the tubular portion (outer pipe portion) of the piston, and each of the outer pipe portion and the inner pipe portion is provided. A through hole is provided, and the through hole (outer hole) of the outer pipe portion penetrates the inner pipe portion as the outer pipe portion of the piston moves in the axial direction relative to the inner pipe portion. A communication state that communicates with the hole (inner hole) and a closed state in which the outer hole is closed by the outer peripheral surface of the inner pipe section are switched. In the air bleeding structure, when the clutch portion is in the clutch-on state (brake state), the outer hole is in the closed state, and when the clutch portion is in the clutch-off state (brake release state). The relative position of the outer hole and the inner hole is set so that the outer hole and the inner hole are in the communication state. Therefore, when the clutch portion is in the clutch-on state (brake state), that is, during winch work in which the power of the winch motor is transmitted to the winch drum, the oil chamber does not communicate with the cooling oil passage. The parts are maintained in the clutch-on state to ensure that the power of the winch motor is properly transmitted to the winch drum. On the other hand, when the clutch portion is in the clutch-off state (brake release state), that is, when the so-called free fall operation in which the free rotation of the winch drum is allowed, the oil chamber communicates with the cooling oil passage. The air mixed in the piping of the hydraulic circuit and the oil chamber connected to the piping is effectively discharged to the outside of these.

The present invention has been made from the above viewpoint. The present invention provides a winch device mounted on a crane, in which a winch drum for winding or unwinding a rope, a winch motor for rotating the winch drum, and a power for the winch motor are provided. A clutch unit capable of performing a switching operation between a clutch-on state transmitted to the winch drum and a clutch-off state in which the winch drum is separated from the winch motor to allow free rotation of the winch drum, A cylinder and a tubular inner pipe part having a cooling oil passage through which cooling oil for cooling the clutch part flows, at least a part of the inner pipe part being arranged in the cylinder; A piston that has an outer pipe portion that surrounds the inner pipe portion in a cylinder, and that axially moves relative to the cylinder and the inner pipe portion within a predetermined movable range. A piston defining a chamber and a negative oil chamber. The outer pipe portion of the piston has an outer hole that penetrates the outer pipe portion in the thickness direction thereof and communicates with one of the positive oil chamber and the negative oil chamber, the inner pipe portion, There is an inner hole that penetrates the inner pipe portion in its thickness direction and communicates with the cooling oil passage. The movable range of the piston is a brake range in which the piston exerts a pressing force on the clutch portion so that the clutch portion is in the clutch on state, and the clutch portion is in the clutch off state. And a free range in which the pressing force is released. The outer hole is closed by the outer peripheral surface of the inner pipe portion when the piston is located in the brake range, and the piston is in the free communication range forming at least a part of the free range. When positioned, at least a part of the outer hole overlaps with the inner hole so that the one oil chamber and the cooling oil passage of the inner pipe portion communicate with each other through the outer hole and the inner hole. The relative position of the outer hole and the inner hole is set.

In this winch device, even when a part of the piping of the hydraulic circuit is detached from the connecting portion and air is mixed into the hydraulic circuit for various purposes such as transportation of a crane, By utilizing the flow of the cooling oil in the cooling oil passage, the air mixed in the pipe or the oil chamber can be effectively discharged. This makes it possible to avoid a reduction in brake responsiveness in the winch device. Specifically, when the piston is located in the brake range, the outer hole in the outer pipe portion of the piston is closed by the outer peripheral surface of the inner pipe portion, so that the pressure of the one oil chamber Is not affected by the cooling oil flowing through the cooling oil passage. This allows the piston to exert the required pressing force on the clutch part and allows the clutch part to be maintained in the clutch-on state. On the other hand, when the piston is located in the free communication range, at least a part of the outer hole overlaps with the inner hole so that the one oil chamber communicates with the cooling oil passage of the inner pipe portion. This allows the oil in the higher pressure space of the one oil chamber and the cooling oil passage to flow into the lower pressure space. That is, when the pressure of the one oil chamber is higher than that of the cooling oil passage in a state where the outer hole communicates with the inner hole, the one oil chamber and the piping of the hydraulic circuit connected to the one oil chamber. The hydraulic oil therein flows into the cooling oil passage together with air, and the air is discharged to the outside of the hydraulic circuit together with the cooling oil flowing in the cooling oil passage. Further, in a state where the outer hole communicates with the inner hole, when the pressure of the one oil chamber is lower than that of the cooling oil passage, the cooling oil in the cooling oil passage enters the one oil chamber. It flows in and flows in the pipe of the hydraulic circuit connected to the one oil chamber together with the working oil, and is discharged to, for example, a tank together with air mixed with the working oil. Therefore, in the present invention, while ensuring that the power of the winch motor is properly transmitted to the winch drum when the clutch portion is in the clutch on state (brake state), the clutch portion is in the clutch off state ( It is possible to effectively discharge the air mixed in the pipe of the hydraulic circuit and the one oil chamber connected to the pipe when the brake is released), that is, during the operation of the free fall. is there.

The winch device is interposed between the one oil chamber and the hydraulic pressure source, and a supply permissible position that allows hydraulic oil discharged from the hydraulic pressure source to be supplied to the one oil chamber and one of the one A mode switching valve capable of switching to a discharge allowable position that allows the hydraulic oil in the oil chamber to be discharged from the one oil chamber, an operation unit that is operated by an operator, the hydraulic power source, and the A brake control valve interposed between the mode switching valve and the operation amount which is the magnitude of the operation received by the operation section when the mode switching valve is switched to the discharge allowable position. A brake control valve that adjusts the supply amount of the hydraulic oil supplied from the hydraulic pressure source to the one oil chamber in accordance with the position of the piston in the movable range according to the operation amount. It is preferable to provide.

In this mode, the differential pressure between the positive oil chamber and the negative oil chamber changes due to the mode switching valve switching between the supply allowable position and the discharge allowable position. The change in the differential pressure causes the piston to move relative to the cylinder in the axial direction. That is, the piston moves from one of the brake range and the free range to the other, whereby the clutch portion switches from one of the clutch on state and the clutch off state to the other. When the mode switching valve is switched to the discharge allowable position, the brake control valve is supplied from the hydraulic pressure source to the one oil chamber according to the operation amount received by the operation section. By adjusting the supply amount of the hydraulic oil, the piston is arranged at a position in the movable range according to the operation amount. Therefore, the operator can arrange the piston within the movable range at a position corresponding to the operation amount by giving an appropriate operation to the operation portion during the free fall work. Therefore, the operator operates the operation portion during the operation of the free fall to arrange the piston within the free communication range, thereby removing the air mixed in the pipe of the hydraulic circuit or the one oil chamber. They can be effectively discharged to the outside.

In the winch device, it is preferable that the free communication range includes a high pressure free communication range that is a range corresponding to a pressure state in which the pressure in the one oil chamber is higher than the pressure in the cooling oil passage.

In this aspect, when the piston is arranged in the high-pressure free communication range, the hydraulic oil in the one oil chamber flows into the cooling oil passage through the outer hole and the inner hole that communicate with each other. This means that when the clutch portion is in the clutch-off state (brake release state), that is, when the free fall is performed, the air mixed with the working oil in the pipe or the one oil chamber is mixed with the working oil. It allows the cooling oil in the cooling oil passage to flow. Thus, the air mixed in the piping of the hydraulic circuit or the one oil chamber can be effectively discharged to the outside of the hydraulic circuit together with the cooling oil through the cooling oil passage.

In the case where the free communication range includes the high pressure free communication range, the free communication range is a range corresponding to a pressure state in which the pressure in the one oil chamber is lower than the pressure in the cooling oil passage. It is more preferable to further include

When the piston is arranged in the high-pressure free communication range and the working oil in the one oil chamber flows into the cooling oil passage through the outer hole and the inner hole many times, the piston is included in the working oil. Foreign matter such as dust that collects may accumulate near the inner hole and near the outer hole. Even in such a case, in this aspect, when the piston is arranged in the low-pressure free communication range, the cooling oil in the cooling oil passage passes through the inner hole and the outer hole that communicate with each other. Flow into. That is, in this aspect, when the piston is arranged in the high-pressure free communication range, the direction opposite to the flow direction of the working oil from the one oil chamber to the cooling oil passage, that is, from the cooling oil passage A flow of cooling oil toward the one oil chamber can be formed. This enables the foreign matter accumulated near the inner hole or near the outer hole to be removed by the flow of the cooling oil in the opposite direction, and the foreign matter causes the inner hole and the outer hole to be removed. It is possible to suppress the clogging of.

In the winch device, the free range further includes a free closing range in which the outer hole is closed by the outer peripheral surface of the inner pipe portion, the movable range of the piston, the brake range, the free closing range, And the free communication range may be arranged in the axial direction.

In this aspect, since the free closed range is provided between the brake range and the free communication range, the time at which the clutch portion switches from the clutch on state to the clutch off state, that is, the piston is At the time of moving from the brake range to the free closed range, the outer hole in the outer pipe portion of the piston does not communicate with the inner hole in the inner pipe portion, and the outer peripheral surface of the inner pipe portion causes It is still blocked. Then, the outer hole communicates with the inner hole when the piston further moves from the free closed range to the free communication range. This makes it possible to provide a time lag between the time when the clutch portion switches from the clutch-on state to the clutch-off state and the time when the outer hole communicates with the inner hole. As a result, when the clutch portion is in the clutch-on state (brake state), the pressure of the one oil chamber is less likely to be affected by the cooling oil flowing through the cooling oil passage, so that the braking state is more stable. Turn into.

In the winch device, one pipe portion of the outer pipe portion and the inner pipe portion has a throttle portion, and the throttle portion is one of the outer hole and the inner hole where the throttle portion is provided. The cross-sectional area of at least a part of the hole that defines at least a part of the hole in the tube part and is defined by the throttle part is a hole in the other tube part of the outer hole and the inner hole in which the throttle part is not provided. Is preferably smaller than the cross-sectional area of

In this aspect, since the throttle portion is provided between the one oil chamber and the cooling oil passage, as compared with the case where the throttle portion is not provided, the outer hole corresponds to the inner pipe portion. It is possible to reduce the speed of pressure change in the one oil chamber when the outer hole is in communication with the inner hole from being closed by the outer peripheral surface.

The crane of the present invention includes a self-propelled lower traveling structure, an upper revolving structure mounted on the lower traveling structure so as to be rotatable about an axis, and the winch device, and the winch drum of the winch device. Is configured to be attachable to and detachable from the upper swing body together with a part of the hydraulic circuit.

According to the crane of the present invention, the winch drum is attached to and detached from the upper swing body together with a part of the hydraulic circuit for various purposes such as transportation of the crane, and as a result, air is mixed into the hydraulic circuit. Even in such a case, the air mixed in the pipe of the hydraulic circuit or the one oil chamber connected to the pipe can be effectively discharged by utilizing the flow of the cooling oil in the cooling oil passage. This makes it possible to suppress a decrease in brake responsiveness in the winch device.

According to the present invention, it is possible to avoid the inconvenience caused by the inclusion of air in the hydraulic circuit in the winch device.

It is a side view which shows the crane which concerns on embodiment of this invention. It is a perspective view showing a wet brake unit, a hydraulic pipe, various ports, etc. in a winch device mounted on the crane. It is a figure which shows the hydraulic circuit in the winch device which concerns on embodiment of this invention. FIG. 4 is an enlarged view of a part of FIG. 3, and is a schematic view showing relative positions of an outer pipe portion and an inner pipe portion of the piston when the piston is arranged in the brake range and the clutch portion is in a clutch on state. is there. FIG. 4 is an enlarged view of a part of FIG. 3, showing a relative position between an outer pipe portion and an inner pipe portion of the piston when the clutch portion is in a clutch-off state and the piston is arranged in a high pressure free communication range. It is a schematic diagram showing. FIG. 4 is an enlarged view of a part of FIG. 3, showing a relative position between an outer pipe portion and an inner pipe portion of the piston when the clutch portion is in a clutch-off state and the piston is arranged in a low pressure free communication range. It is a schematic diagram showing. In the winch device, it is a graph showing the relationship between the position of the piston within the movable range of the piston and the pressure in the positive oil chamber. In the winch device, it is a graph showing the relationship between the position of the piston within the movable range of the piston and the communication area that communicates the positive oil chamber and the cooling oil passage. FIG. 6 is a cross-sectional view showing the relative positions of the outer pipe portion and the inner pipe portion of the piston when the piston is arranged in the brake range and the clutch portion is in the clutch on state. FIG. 6 is a cross-sectional view showing a relative position between an outer pipe portion and an inner pipe portion of the piston when the clutch portion is in a clutch-off state and the piston is arranged in a high pressure free communication range. It is a figure which shows the hydraulic circuit in the winch device which concerns on the modification of the said embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[crane]
FIG. 1 is a side view showing a crane 100 including a winch device 10 according to an embodiment of the present invention. As shown in FIG. 1, the crane 100 is capable of self-propelled lower traveling body 101, upper revolving body 103 mounted on lower traveling body 101 so as to be rotatable around an axis, and undulating on upper revolving body 103. The boom 104 attached thereto, the hook 105 suspended from the tip of the boom 104 via the rope R, the gantry 107 attached to the upper swing body 103, and the winch device 10 having the winch drum 1 are provided. When the jib is attached to the tip of the boom 104, the hook 105 is suspended from the tip of the jib via the rope R.

The winch device 10 is for winding the rope R connected to the hook 105 around the winch drum 1 or unwinding it from the winch drum 1 to cause the hook 105 to perform an elevating operation for hanging work. The rope R is paid out from the winch drum 1, passes through the tip of the boom 104, and is hung from the tip of the boom 104 to suspend the hook 105. A suspended load 106 is suspended on the hook 105. The winch drum 1 winds the rope R by rotating in one rotation direction (winding rotation direction) around the rotation axis thereof, thereby raising the hook 105. The winch drum 1 is rotated in the direction opposite to the winding rotation direction to pay out the rope R, thereby lowering the hook 105.

As shown in FIG. 1, in the present embodiment, the winch drum 1 is provided on the boom 104. The winch drum 1 is supported by the boom 104 such that its rotation axis and the vehicle width direction of the crane 100 coincide with each other. Although not shown in FIG. 1, a part of the piping in the hydraulic circuit of the winch device 10 is arranged so as to straddle between the upper swing body 103 and the boom 104.

FIG. 2 is a perspective view showing the wet brake unit 2, hydraulic pipes, various ports and the like in the winch device 10. The hydraulic pipe connected to the wet brake unit 2 of the winch device 10 is connected to the connecting portion via the coupler, so that the coupler can be attached to and detached from the connecting portion. Therefore, when the boom 104 is removed from the upper swing body 103 to transport the crane 100, the winch drum 1 supported by the boom 104 can be easily separated from the upper swing body 103 together with a part of the hydraulic pipe. it can. In particular, it is preferable that all hydraulic pipes connected to the winch device 10 are connected to the connecting portion by the coupler.

[Winch device]
Hereinafter, the winch device 10 according to the embodiment of the present invention will be described in detail.

FIG. 3 is a diagram showing a hydraulic circuit in the winch device 10 according to the embodiment of the present invention. As shown in FIG. 3, the winch device 10 includes a wet brake unit 2, a winch motor 20, a speed reducer 21, a mode switching valve 22, and a hydraulic pump 24 as a hydraulic power source, in addition to the winch drum 1 described above. The brake operating device 25, the rotation direction switching valve 27, the hydraulic pump 28, the winch operating device 29, the mode switching switch 30, and the controller 40 are further included.

The winch motor 20 is a drive source for rotationally driving the winch drum 1. The winch motor 20 is a hydraulic motor having an output shaft 201 that rotates by receiving hydraulic oil supplied from the hydraulic pump 28. The winch motor 20 has a first port 20a and a second port 20b, and the supply of hydraulic oil to one of these ports causes the output shaft 201 to rotate in a direction corresponding to the one port. And discharge the hydraulic oil from the other port.

The rotation direction switching valve 27 is interposed between the hydraulic pump 28 and the winch motor 20, and supplies hydraulic oil for driving the winch motor 20 from the hydraulic pump 28 to the first port 20a and the second port of the winch motor 20. 20b is a control valve for controlling the rotation speed of the winch motor 20 by controlling the rotation direction of the winch motor 20 while controlling the rotation direction of the winch motor 20 by adjusting the flow rate of the hydraulic oil supplied to the winch motor 20. .. The rotation direction switching valve 27 has pilot ports 27a and 27b.

The winch operation device 29 has an operation lever 29a as an operation member and a pilot valve 29b. The operation lever 29a rotates in that direction when an operator operates the operation lever 29a. The pilot valve 29b has an unillustrated inlet port connected to an unillustrated pilot pump and a pair of unillustrated outlet ports. The pair of outlet ports are connected to pilot ports 27a and 27b of the rotation direction switching valve 27 via pilot lines, respectively. The pilot valve 29b is opened to allow the pilot pressure corresponding to the magnitude of the operation to be supplied from the pilot pump to the pilot ports 27a and 27b corresponding to the operation direction of the operation lever 29a. Speak.

The rotation direction switching valve 27 is held at the neutral position (center position in FIG. 3) when the pilot pressure is not input to the pilot ports 27a and 27b. At this neutral position, the hydraulic pump 28 and the winch motor 20 are disconnected from each other and the center bypass line is opened, whereby the hydraulic oil from the hydraulic pump 28 returns to the tank T1 as it is through the center bypass line.

When the pilot pressure is supplied to the pilot port 27a, the rotation direction switching valve 27 moves from the neutral position to the first drive position (upper position in FIG. 3) with a stroke corresponding to the magnitude of the pilot pressure. Shift to. At the first drive position, the hydraulic oil from the hydraulic pump 28 is supplied to the first port 20a of the winch motor 20 at a flow rate corresponding to the stroke, and the hydraulic oil discharged from the second port 20b is supplied to the tank T1. Return.

Further, when the pilot pressure is supplied to the pilot port 27b, the rotation direction switching valve 27 has a stroke corresponding to the magnitude of the pilot pressure from the neutral position to the second drive position (the lower position in FIG. 3). Shift to. At the second drive position, the hydraulic oil from the hydraulic pump 28 is supplied to the second port 20b of the winch motor 20 at a flow rate corresponding to the stroke, and the hydraulic oil discharged from the first port 20a is supplied to the tank T1. Return.

The speed reducer 21 is interposed between the output shaft 201 of the winch motor 20 and the winch drum 1 to transmit the power of the winch motor 20 to the winch drum 1, and is composed of, for example, a planetary gear mechanism. There is. A plate (for example, the inner plate 8) of the clutch unit 4 described later is connected to the carrier shaft 211 of the speed reducer 21.

The wet brake unit 2 has a cylinder portion 3 and a clutch portion 4.

The clutch unit 4 is between a clutch-on state in which the power of the winch motor 20 is transmitted to the winch drum 1 and a clutch-off state in which the winch drum 1 is separated from the winch motor 20 and allows free rotation of the winch drum 1. It is configured to be switchable with. The clutch unit 4 includes a clutch case 7, an inner plate 8 arranged inside the clutch case 7, an outer plate 9, and a spring 11.

The cylinder portion 3 has a cylinder 5, an inner pipe portion 13, and a piston 6. The cylinder 5 has a cylindrical shape and has a housing space defined by an inner peripheral surface thereof. The cylinder 5 is fixed to the clutch case 7 or formed integrally with the clutch case 7. The accommodation space of the cylinder 5 and the accommodation space defined by the inner peripheral surface of the clutch case 7 communicate with each other.

The inner pipe portion 13 is a tubular (cylindrical) member and has a cooling oil passage 14 defined by the inner peripheral surface thereof. The inner pipe portion 13 has openings 13a and 13b at one end (upstream end) and the other end (downstream end) of the central axis in the axial direction (see FIG. 4). When the pump 36 for sending the cooling oil to the upstream opening 13a of the inner pipe portion 13 is operated, the cooling oil flows into the cooling oil passage 14 from the upstream opening 13a at the upstream end, and the cooling oil passage It is guided by 14 and flows out from the downstream opening 13b at the downstream end. The cooling oil flowing out from the downstream opening 13b is guided to the hollow portion of the piston 6 described later and supplied to the clutch portion 4 to cool the clutch portion 4. The cooling oil that has cooled the clutch unit 4 is discharged from the clutch unit 4 and collected in the tank 37. In the present embodiment, the cooling oil is the same as the hydraulic oil discharged from the hydraulic pump 24, but may be different from the hydraulic oil.

In the present embodiment, most of the inner pipe portion 13 including the downstream opening portion 13b is arranged in the cylinder 5. The inner pipe portion 13 is connected to the cylinder 5 at a cylinder opening portion provided at one end of the cylinder 5 and extends toward the clutch portion 4. The inner pipe portion 13 is integrated with the cylinder 5 and does not move relative to the cylinder 5. The inner pipe portion 13 may be molded separately from the cylinder 5 and then fixed to the cylinder 5, or may be integrally molded with the cylinder 5.

The piston 6 is configured to be able to move relative to the cylinder 5 and the inner pipe portion 13 in the axial direction within a predetermined movable range. The piston 6 has an outer pipe portion 61, a flange portion 62, and a pressing portion 63.

The outer pipe portion 61 is a tubular (cylindrical) portion that surrounds the inner pipe portion 13. The outer tube portion 61 has openings 6a and 6b at one end (upstream end) and the other end (downstream end) of the central axis in the axial direction (see FIG. 4). The inner pipe portion 13 is inserted into a columnar hollow portion defined by the inner peripheral surface of the outer pipe portion 61. The inner peripheral surface of the outer pipe portion 61 radially faces the outer peripheral surface of the inner pipe portion 13, and is in contact with or close to the outer peripheral surface. The outer pipe portion 61 is configured to be slidable with respect to the inner pipe portion 13. The gap between the inner peripheral surface of the outer pipe portion 61 and the outer peripheral surface of the inner pipe portion 13 is designed to be small so that the amount of hydraulic oil and cooling oil leaking from the gap is small.

The upstream opening 6a at the upstream end of the outer pipe portion 61 is located between the upstream opening 13a and the downstream opening 13b of the inner pipe portion 13 in the axial direction. The downstream opening portion 6b of the outer pipe portion 61 is located closer to the clutch portion 4 than the downstream opening portion 13b of the inner pipe portion 13 in the axial direction. The outer pipe portion 61 extends from the upstream opening 6a toward the clutch portion 4. When the cooling oil flowing through the cooling oil passage 14 in the inner pipe portion 13 flows out from the downstream opening portion 13b, the cooling oil is guided to the hollow portion of the outer pipe portion 61 and flows out from the downstream opening portion 6b of the outer pipe portion 61. And then supplied to the clutch unit 4. Therefore, the hollow portion of the outer pipe portion 61 has a function as a guide path for guiding the cooling oil.

The flange portion 62 is a portion having a shape that protrudes radially outward from the outer peripheral surface of the outer pipe portion 61 in a ring shape. The flange portion 62 is provided on the outer peripheral surface of the outer pipe portion 61 at an intermediate portion between the upstream opening portion 6a and the downstream opening portion 6b of the outer pipe portion 61. An outer peripheral surface on the radially outer side of the flange portion 62 is radially opposed to the inner peripheral surface of the cylinder 5 and is in contact with or close to the inner peripheral surface. The flange portion 62 is configured to be slidable with respect to the cylinder 5.

The piston 6 and the cylinder 5 define a positive oil chamber 3a and a negative oil chamber 3b. Specifically, the outer peripheral surface of the outer pipe portion 61, the pair of outer surface of the flange portion 62 on both sides in the axial direction, the inner peripheral surface of the cylinder 5, and the pair of inner surfaces on both sides in the axial direction of the cylinder 5. The side surface defines a positive oil chamber 3a and a negative oil chamber 3b.

The positive chamber 3a generates a pressure in a direction in which the clutch portion 4 is in the clutch-on state. The negative oil chamber 3b generates a pressure in a direction in which the clutch portion 4 is in the clutch-off state.

The pressing portion 63 is a portion having a shape projecting radially outward from the outer peripheral surface of the outer pipe portion 61 in a ring shape. The pressing portion 63 is provided on the outer peripheral surface of the outer pipe portion 61 at a portion closer to the clutch portion 4 than the flange portion 62. Specifically, the pressing portion 63 is provided at the other end (downstream end) of the outer pipe portion 61 in the axial direction. When the piston 6 moves in the axial direction, the clutch portion 4 switches between the clutch on state (brake applied state) and the clutch off state (brake released state). Specifically, as the piston 6 moves in the axial direction toward the clutch portion 4, the pressing portion 63 of the piston 6 contacts the inner plate 8 and the outer plate 9 of the clutch portion 4. By thus applying a pressing force to these, the clutch portion 4 is brought into the clutch-on state. On the other hand, as the piston 6 moves in the axial direction away from the clutch portion 4, the inner plate 8 and the outer plate 9 are separated from each other, and the clutch portion 4 is in the clutch-off state.

The spring 11 biases the pressing portion 63 of the piston 6 in a direction in which the clutch portion 4 is in a clutch-on state, that is, in a direction in which the piston 6 approaches the clutch portion 4. The spring 11 is arranged between the side surface of the clutch case 7 and the side surface of the pressing portion 63.

The mode switching valve 22 is a control valve for switching the clutch unit 4 between a clutch-on state (brake state) and a clutch-off state (brake release state) in cooperation with a brake operating device 25 described later. The mode switching valve 22 is interposed between the hydraulic pump 24 and the positive oil chamber 3a.

The mode switching valve 22 has a supply permissible position (the left side position in FIG. 3) that allows the hydraulic oil from the hydraulic pump 24 to be supplied to the positive oil chamber 3a, and the hydraulic oil in the positive oil chamber 3a is the positive oil. It is configured to be able to switch to a discharge allowable position (right side position in FIG. 3) that allows discharge from the chamber 3a. In this embodiment, the mode switching valve 22 is composed of a solenoid valve.

The mode changeover switch 30 is a switch for switching between the brake mode and the free fall mode, and is provided in the cab of the crane, for example, so that it can be operated by the operator. The mode changeover switch 30 is configured to input a free fall mode signal to the controller 40 when the switch is turned on, and to input a brake mode signal to the controller 40 when the switch is turned off. Has been done.

When the mode changeover switch 30 is turned off, the mode changeover valve 22 receives a command from the controller 40, the solenoid is de-energized, and the discharge allowance position is changed to the supply allowance position (left side position in FIG. 3). Switch. When the mode switching valve 22 switches from the discharge allowable position to the supply allowable position, the mode switching valve 22 allows the hydraulic oil from the hydraulic pump 24 to be supplied to the positive oil chamber 3a. On the other hand, when the mode changeover switch 30 is turned on, the solenoid of the mode changeover valve 22 is excited in response to a command from the controller 40, and the supply allowance position to the discharge allowance position (right side position in FIG. 3). Switch to. When the mode switching valve 22 switches from the supply allowable position to the discharge allowable position, the mode switching valve 22 prevents the hydraulic oil from the hydraulic pump 24 from being supplied to the positive oil chamber 3a, while Allow the hydraulic oil in 3a to return to the tank T2.

The brake operation device 25 has an operation pedal (foot pedal) 25a as an operation unit that receives an operation by an operator, and a brake control valve 25b. The brake control valve 25b is interposed between the hydraulic pump 24 and the mode control valve 22, and operates according to the operation received by the operation pedal 25a.

Specifically, the positive line 31 (pipe 31) connected to the inlet port 3A of the positive oil chamber 3a is connected to one outlet port of the mode switching valve 22. One inlet port of the mode switching valve 22 is connected to the hydraulic pump 24, and the other inlet port is connected to the outlet port of the brake control valve 25b. One inlet port of the brake control valve 25b is connected to the tank T2, and the other inlet port of the brake control valve 25b is connected to the hydraulic pump 24. The negative line 32 (pipe 32) connected to the inlet port 3B of the negative oil chamber 3b is directly connected to the hydraulic pump 24.

The brake control valve 25b supplies the positive oil chamber 3a from the hydraulic pump 24 according to the operation amount received by the operation pedal 25a when the mode switching valve 22 is switched to the discharge allowable position. The piston 6 is arranged at a position corresponding to the operation amount within the movable range by adjusting the supplied amount of the hydraulic oil.

Specifically, in the brake control valve 25b, the operation pedal 25a is not operated when the mode changeover switch 30 is in the ON state (the mode changeover valve 22 is in the discharge allowable position (right side position in FIG. 3)). At some times, the hydraulic oil in the positive oil chamber 3a is allowed to return to the tank T2 via the mode switching valve 22. On the other hand, when the operation pedal 25a is operated when the mode changeover switch 30 is in the ON state (the mode changeover valve 22 is in the discharge allowable position), the brake control valve 25b is in accordance with the operation amount of the operation pedal 25a. The valve is opened to allow the hydraulic oil from the hydraulic pump 24 to be supplied to the positive oil chamber 3a via the mode switching valve 22.

The controller 40 comprises a central processing unit (CPU), a ROM that stores various control programs, a RAM used as a work area of the CPU, and the like.

4, FIG. 5, and FIG. 6 are enlarged views of a part of FIG. FIG. 4 is a schematic diagram showing the relative positions of the outer pipe portion 61 and the inner pipe portion 13 of the piston 6 when the clutch portion 4 is in the clutch-on state. 5 and 6 are schematic views showing the relative positions of the outer pipe portion 61 and the inner pipe portion 13 of the piston 6 when the clutch portion 4 is in the clutch-off state. FIG. 7 is a graph showing the relationship between the position of the piston 6 within the movable range of the piston 6 and the pressure in the positive oil chamber 3a. FIG. 8 is a graph showing the relationship between the position of the piston 6 within the movable range of the piston 6 and the communication area that communicates the positive oil chamber 3a with the cooling oil passage 14.

As shown in FIG. 4, the outer pipe portion 61 of the piston 6 has an outer hole H1 that penetrates the outer pipe portion 61 in its thickness direction and communicates with the positive oil chamber 3a. The inner pipe portion 13 has an inner hole H2 that penetrates the inner pipe portion 13 in its thickness direction and communicates with the cooling oil passage 14. The outer hole H1 is provided in the lower portion of the outer pipe portion 61, and the inner hole H2 is provided in the lower portion of the inner pipe portion 13.

The shapes of the outer hole H1 and the inner hole H2 are not particularly limited, and include, for example, a circular shape, an elliptical shape, a long hole formed along the circumferential direction, a long hole formed along the axial direction, and the like. Various shapes of can be adopted.

As shown in FIGS. 7 and 8, the movable range of the piston 6 in the axial direction is from a position A where the piston 6 is closest to the clutch portion 4 to a position E where the piston 6 is farthest from the clutch portion 4. The range is up to.

The movable range of the piston 6 includes a brake range R1 and a free range R2. As shown in FIG. 4, FIG. 7 and FIG. 8, the brake range R1 is within the movable range of the piston 6, and the piston 6 is in the clutch part 4 so that the clutch part 4 is in the clutch-on state. This is the range where the pressing force is applied to. When the piston 6 is arranged within the braking range R1, the outer hole H1 is closed by the outer peripheral surface of the inner pipe portion 13. As shown in FIGS. 7 and 8, the brake range R1 is a range from a position A where the piston 6 is closest to the clutch portion 4 to a position B where the piston 6 moves away from the position A.

As shown in FIG. 5, FIG. 6, FIG. 7 and FIG. 8, the free range R2 is relative to the clutch part 4 so that the clutch part 4 is in the clutch-off state in the movable range of the piston 6. This is a range in which the pressing force by the piston 6 is released. As shown in FIGS. 7 and 8, the free range R2 is a range from the position B to the position E where the piston 6 is farthest from the clutch portion 4.

The free range R2 includes a free closed range R21 and a free communication range R22. As shown in FIGS. 7 and 8, the free closing range R21 is a range of the free range R2 in which the outer hole H1 is closed by the outer peripheral surface of the inner pipe portion 13. The free closed range R21 is a range from the position B to a position C where the piston 6 moves away from the position B.

As shown in FIGS. 5, 6, 7 and 8, in the free communication range R22, at least a part of the outer hole H1 of the free range R2 overlaps with the inner hole H2. 3a and the cooling oil passage 14 of the inner pipe portion 13 communicate with each other. The free communication range R22 is a range from the position C to a position E where the piston 6 is farthest from the clutch portion 4.

As shown in FIGS. 7 and 8, the free communication range R22 includes a high pressure free communication range R221 and a low pressure free communication range R222. The high-pressure free communication range R221 is a range of the free communication range R22 in which the pressure in the positive oil chamber 3a is higher than the pressure in the cooling oil passage 14. The high-pressure free communication range R221 is a range from the position C to a position D where the piston 6 moves away from the position C. The low-pressure free communication range R222 is a range of the free communication range R22 corresponding to a pressure state in which the pressure in the positive oil chamber 3a is lower than the pressure in the cooling oil passage 14. The low-pressure free communication range R222 is a range from the position D to a position E where the piston 6 is farthest from the clutch portion 4.

As shown in FIGS. 7 and 8, the brake range R1, the free closing range R21, and the free communication range R22 are arranged in this order in the axial direction. The brake range R1, the free closed range R21, the high pressure free communication range R221, and the low pressure free communication range R222 are arranged in this order in the axial direction.

In this embodiment, the relative positions of the outer hole H1 and the inner hole H2 are set so as to satisfy the following conditions. That is, when the piston 6 is located in any one of the brake range R1 and the free closing range R21, the outer hole H1 in the outer pipe part of the piston 6 is formed in the inner pipe part 13. Blocked by the outer peripheral surface. When the piston 6 is located in the free communication range R22, that is, when the piston 6 is located in any one of the high pressure free communication range R221 and the low pressure free communication range R222, the outer hole H1 At least part of which overlaps with the inner hole H2 so that the positive oil chamber 3a communicates with the cooling oil passage 14 of the inner pipe portion 13.

When the mode switching valve 22 is switched to the supply allowable position, the piston 6 moves to the position closest to the clutch portion 4 in the movable range as shown in FIGS. 4, 7, and 8. It is located at A. Further, when the mode switching valve 22 is switched to the discharge allowable position and the operation amount of the operation pedal 25a is the maximum operation amount, that is, the operation pedal 25a is most depressed. At some time, the piston 6 is arranged at the position A closest to the clutch portion 4 in the movable range as shown in FIGS. 4, 7, and 8. As shown in FIG. 7, when the piston 6 is in the position A, the pressure in the positive oil chamber 3a is highest.

As shown in FIG. 7, when the mode switching valve 22 is switched to the discharge allowable position and the operation amount of the operation pedal 25a gradually decreases from the maximum operation amount, the operation from the pump 24 is started. The supply amount of oil supplied to the positive oil chamber 3a gradually decreases. As a result, the pressure in the positive oil chamber 3a gradually decreases, and the piston 6 moves from the position A toward the position E according to the operation amount.

When the mode switching valve 22 is switched to the discharge allowable position and the operation amount of the operation pedal 25a is the minimum operation amount, that is, the operation pedal 25a is not depressed at all. At this time, the piston 6 is arranged at the position E farthest from the clutch portion 4 in the movable range as shown in FIGS. 6, 7, and 8. As shown in FIG. 7, when the piston 6 is at the position E, the pressure in the positive oil chamber 3a becomes the lowest.

Further, as shown in FIG. 8, when the piston 6 is arranged in any one of the brake range R1 and the free closing range R21, that is, when the piston 6 extends from the position A to the position C. When arranged within the range, since the outer hole H1 is closed by the outer peripheral surface of the inner pipe portion 13, the communication area that connects the positive oil chamber 3a and the cooling oil passage 14 is the smallest. .. Note that, in FIG. 8, when the piston 6 is arranged in any one of the brake range R1 and the free closed range R21, a communication area for communicating the positive oil chamber 3a and the cooling oil passage 14 is It does not become zero because there is a slight gap between the inner peripheral surface of the outer pipe portion 61 and the outer peripheral surface of the inner pipe portion 13.

Then, when the piston 6 moves in a direction away from the clutch portion 4 from the position C, that is, when the piston 6 enters the free communication range R22, the positive oil chamber 3a and the cooling oil passage 14 are communicated with each other. The communication area for communication gradually increases.

Specifically, in this embodiment, as described later, the inner pipe portion 13 has a narrowed portion 16 (see FIGS. 9 and 10), and the opening of the narrowed portion 16 is an inner portion of the inner pipe portion 13. It constitutes a part of the hole H2. In the present embodiment, the opening area of the narrowed portion 16 is smaller than the opening area of the outer hole H1 and is set to the size shown in the graph of FIG. When the piston 6 moves in a direction away from the clutch portion 4 from the position C, the communication area that communicates the positive oil chamber 3a and the cooling oil passage 14 is equal to the opening area of the throttle portion 16. It gets bigger and bigger. After the communication area matches the opening area of the throttle section 16, even if the piston 6 moves further in the direction away from the clutch section 4, the communication area has the same size as the opening area of the throttle section 16. Maintained.

In the present embodiment, the opening area of the throttle portion 16 is such that when the piston 6 is located between the position C and the position D, that is, the piston 6 is located within the high pressure free communication range R221. The size of the communication area is set so as to match the opening area of the narrowed portion 16 during the operation. However, the opening area of the throttle unit 16 is not limited to the specific example shown in FIG. 8, and, for example, when the piston 6 is in a position between the position D and the position E, that is, when the piston 6 is The size may be set such that the communication area matches the opening area of the throttle portion 16 when located in the low-pressure free communication range R222. Further, the opening area of the throttle portion 16 may be set to a size such that the communication area continues to increase while the piston 6 moves from the position C to the position E. In this case, When the piston 6 is at the position E, the communication area that connects the positive oil chamber 3a and the cooling oil passage 14 is the largest.

As shown in FIG. 7, the pressure of the cooling oil passage 14 is set to a constant value (0.3 MPa in the specific example of FIG. 7), and the piston 6 is arranged within the free communication range R22. Is smaller than the upper limit pressure and larger than the lower limit pressure. That is, the pressure of the cooling oil passage 14 is smaller than the pressure of the positive oil chamber 3a when the piston 6 is arranged at the position C, and the positive pressure when the piston 6 is arranged at the position E. It is larger than the pressure in the oil chamber 3a. The pressure of the cooling oil passage 14 can be adjusted, for example, by changing the capacity of the pump 36 for supplying the cooling oil to the cooling oil passage 14.

The winch device 10 according to the above embodiment performs the following operation.

As shown in FIG. 3, when the mode changeover switch 30 is turned off and the winch device 10 is changed over to the brake mode, the solenoid of the mode changeover valve 22 is de-energized, and the mode changeover valve 22 moves from the discharge allowable position. It switches to the supply allowable position (the position on the left side in FIG. 3). In this case, the same pressure is applied to the positive oil chamber 3a and the negative oil chamber 3b. Therefore, the piston 6 is arranged at the position A by the biasing force of the spring 11, and the pressing portion 63 of the piston 6 applies a pressing force to the inner plate 8 and the outer plate 9 so that they are in contact with each other. As a result, the winch drum 1 and the winch motor 20 are connected via the reduction gear 21 (clutch on state, brake state).

On the other hand, when the mode changeover switch 30 is turned on and the winch device 10 is changed over to the free fall mode, the solenoid of the mode changeover valve 22 is energized, and the mode changeover valve 22 moves from the supply allowable position to the discharge allowable position (Fig. 3, the positive oil chamber 3a is connected to the brake control valve 25b of the brake operating device 25.

In this case, the operator turns on the mode selector switch 30 in a state in which the operation pedal 25a is operated so that the operation amount of the operation pedal 25a becomes the maximum operation amount, that is, the operation pedal 25a is fully depressed. In this state, since the same pressure is applied to the positive oil chamber 3a and the negative oil chamber 3b, the piston 6 is arranged at the position A, and the pressing portion 63 of the piston 6 contacts the inner plate 8 and the outer plate 9. Pressing force is applied to these. As a result, the winch drum 1 and the winch motor 20 are connected via the reduction gear 21 (brake state).

Next, when the operation amount of the operation pedal 25a gradually decreases from the maximum operation amount, the opening degree of the brake control valve 25b gradually decreases, so that the hydraulic oil from the pump 24 is supplied to the positive oil chamber 3a. Supply gradually decreases. As a result, the pressure in the positive oil chamber 3a gradually decreases, and the piston 6 moves from the position A toward the position E according to the operation amount. Then, as shown in FIG. 8, when the piston 6 reaches the position C, that is, when the piston 6 reaches the free communication range R22, the outer hole H1 of the outer pipe portion 61 and the inner pipe portion Communication with the inner hole H2 of 13 is started. As described above, in the present embodiment, as shown in FIGS. 7 and 8, the communication start point (position C) at which the outer hole H1 starts communicating with the inner hole H2 is at the pressure of the positive oil chamber 3a in the cooling oil passage 14. It is closer to the position A than the same pressure point (position D) where the pressure is the same. In other words, when the pressure in the positive oil chamber 3a is higher than the pressure in the cooling oil passage 14, the communication between the outer hole H1 and the inner hole H2 is started.

As shown in FIG. 7, when the piston 6 is arranged in the high pressure free communication range R221 of the free communication range R22, the pressure of the positive oil chamber 3a is higher than the pressure of the cooling oil passage 14. Since it is large, the working oil existing between the positive oil chamber 3a and the hydraulic pump 24 flows into the cooling oil passage 14 through the outer hole H1 and the inner hole H2 together with the air mixed in the working oil. The hydraulic oil and the air flowing into the cooling oil passage 14 are supplied to the clutch portion 4 together with the cooling oil flowing in the cooling oil passage 14, and then discharged from the clutch portion 4 to the outside and collected in the tank 37. .. Thereby, the air mixed in the hydraulic oil in the hydraulic circuit is effectively discharged to the outside of the hydraulic circuit.

Further, as shown in FIG. 7, when the piston 6 is arranged in the low pressure free communication range R222 of the free communication range R22, the pressure of the positive oil chamber 3a is the pressure of the cooling oil passage 14. Therefore, a part of the cooling oil flowing through the cooling oil passage 14 flows into the positive oil chamber 3a. The cooling oil flowing into the positive oil chamber 3a is collected in the tank T2 through the positive line 31. Thereby, the air mixed in the hydraulic oil in the hydraulic circuit is effectively discharged to the outside of the hydraulic circuit. Further, the flow of the cooling oil from the cooling oil passage 14 toward the positive oil chamber 3a removes the foreign matter accumulated near the inner hole H2 and near the outer hole H1. The clogging of H2 and the outer hole H1 is suppressed.

The operator can also reciprocate the piston 6 between the high pressure free communication range R221 and the low pressure free communication range R222 by repeatedly increasing and decreasing the operation amount of the operation pedal 25a. In such a case, the effect of discharging the air and the effect of removing the foreign matter can be more significantly obtained.

FIG. 9 is a cross-sectional view showing the relative positions of the outer pipe portion 61 and the inner pipe portion 13 of the piston 6 when the piston 6 is arranged in the brake range R1 and the clutch portion 4 is in the clutch-on state. FIG. 10 shows the relative positions of the outer pipe portion 61 and the inner pipe portion 13 of the piston 6 when the clutch portion 4 is in the clutch-off state and the piston 6 is arranged in the high pressure free communication range R221. FIG.

As shown in FIGS. 9 and 10, the inner tube portion 13 has a throttle portion 16. The narrowed portion 16 defines a part of the inner hole H2 in the inner pipe portion 13. A cross-sectional area (opening area) of a part of the inner hole H2 defined by the narrowed portion 16 is smaller than a cross-sectional area (opening area) of the outer hole H1 in the outer pipe portion 61.

Specifically, the inner hole H2 is defined by an inner peripheral surface of the first enlarged portion 15 located radially outside the narrowed portion 16 and an inner peripheral surface of the narrowed portion 16. And an inner inner hole H23 defined by the inner peripheral surface of the second enlarged portion 17 positioned radially inward of the narrowed portion 16. The cross-sectional area (opening area) of the outer inner hole H21 is larger than the cross-sectional area (opening area) of the portion of the outer hole H1 of the outer tube portion 61 adjacent to the outer inner hole H21. The cross-sectional area (opening area) of the intermediate inner hole H22 defined by the inner peripheral surface of the narrowed portion 16 is smaller than the cross-sectional area (opening area) of the outer hole H1 of the outer tube portion 61, It is smaller than the cross-sectional area (opening area) of H21. The cross-sectional area (opening area) of the inner inner hole H23 is larger than the cross-sectional area (opening area) of the intermediate inner hole H22 defined by the inner peripheral surface of the narrowed portion 16.

In the present embodiment, the inner hole H2 includes the outer inner hole H21. This enables the outer hole H1 to communicate with the inner hole H2 in a wide range in the axial direction. Further, the inner hole H2 includes an intermediate inner hole H22 defined by the inner peripheral surface of the narrowed portion 16. This means that the outer hole H1 is changed from the state in which the outer hole H1 is blocked by the outer peripheral surface of the inner tube portion 13 to the inner hole H2, as compared with the case where the narrowed portion 16 is not provided. It is possible to reduce the speed of the pressure change in the positive oil chamber 3a when changing to the communication state. The inner hole H2 includes the inner inner hole H23. This means that when a flow of cooling oil from the cooling oil passage 14 to the positive oil chamber 3a is formed, the cooling oil in the cooling oil passage 14 is defined by the inner peripheral surface of the throttle portion 16. It facilitates the flow into the inner hole H22.

FIG. 11 is a diagram showing a hydraulic circuit in the winch device 10 according to the modified example of the embodiment. The hydraulic circuit in the modified example shown in FIG. 11 is different from the hydraulic circuit in the embodiment shown in FIG. 3 in the following points, and the other configurations are the same as the hydraulic circuit in the embodiment shown in FIG. Only the points different from the hydraulic circuit in the above embodiment will be described below.

In the hydraulic circuit according to the modification, a positive line 31 is connected to the inlet port 3A of the positive oil chamber 3a. The positive line 31 is not connected to the mode switching valve 22 and the hydraulic pump 24 as in the above embodiment, but is connected to the tank T3.

A negative line 32 is connected to the inlet port 3B of the negative oil chamber 3b. The negative line 32 is not directly connected to the hydraulic pump 24 as in the above embodiment, but is connected to one outlet port of the mode switching valve 22. Then, one inlet port of the mode switching valve 22 is connected to the tank T2. The other inlet port of the mode switching valve 22 is connected to the outlet port of the brake control valve 25b. One inlet port of the brake control valve 25b is connected to the hydraulic pump 24. The other inlet port of the brake control valve 25b is connected to the tank T2.

As shown in FIG. 11, in the modification, the outer pipe portion 61 of the piston 6 has an outer hole H1 that penetrates the outer pipe portion 61 in its thickness direction and communicates with the negative oil chamber 3b. The inner pipe portion 13 has an inner hole H2 that penetrates the inner pipe portion 13 in its thickness direction and communicates with the cooling oil passage 14. When the outer hole H1 is closed by the outer peripheral surface of the inner pipe portion 13 when the piston 6 is located in the brake range R1, and the piston 6 is located in the free communication range R22. Of the outer hole H1 and the inner hole H2 so that at least a part of the outer hole H1 overlaps with the inner hole H2 so that the negative oil chamber 3b and the cooling oil passage 14 of the inner pipe portion 13 communicate with each other. The relative position is set.

The winch device 10 according to the modified example of the above embodiment performs the following operation.

As shown in FIG. 11, when the mode changeover switch 30 is turned off and the winch device 10 is changed over to the brake mode, the solenoid of the mode changeover valve 22 is de-energized and the mode changeover valve 22 moves from the supply allowable position. It switches to the discharge allowable position (the position on the left side in FIG. 11). In this case, the same pressure is applied to the positive oil chamber 3a and the negative oil chamber 3b. Therefore, the urging force of the spring 11 causes the pressing portion 63 of the piston 6 to apply a pressing force to the inner plate 8 and the outer plate 9 so that they are in contact with each other. As a result, the winch drum 1 and the winch motor 20 are connected via the speed reducer 21 (clutch on state, brake state).

On the other hand, when the mode changeover switch 30 is turned on and the winch device 10 is changed over to the free fall mode, the solenoid of the mode changeover valve 22 is energized, and the mode changeover valve 22 moves from the discharge allowable position to the supply allowable position (Fig. 11) and the negative oil chamber 3b is connected to the brake control valve 25b of the brake operating device 25.

In this case, the operator turns on the mode selector switch 30 in a state in which the operation pedal 25a is operated so that the operation amount of the operation pedal 25a becomes the maximum operation amount, that is, the operation pedal 25a is fully depressed. In this state, the negative oil chamber 3b is connected to the tank T2, and the same pressure is applied to the positive oil chamber 3a and the negative oil chamber 3b. Therefore, the piston 6 is arranged at the position A closest to the clutch portion 4, The pressing portion 63 of 6 applies a pressing force to the inner plate 8 and the outer plate 9 so that they are in contact with each other. As a result, the winch drum 1 and the winch motor 20 are connected via the reduction gear 21 (brake state).

Next, when the operation amount of the operation pedal 25a gradually decreases from the maximum operation amount, the opening degree of the brake control valve 25b gradually decreases, so that the hydraulic oil from the pump 24 is supplied to the negative oil chamber 3b. Supply gradually increases. As a result, the pressure of the negative oil chamber 3b gradually increases, and the piston 6 moves from the position A toward the position E farthest from the clutch portion 4 according to the operation amount. Then, when the piston 6 reaches the free communication range R22, the communication between the outer hole H1 of the outer pipe portion 61 and the inner hole H2 of the inner pipe portion 13 is started.

When the piston 6 is arranged in the low pressure free communication range R222 of the free communication range R22, the pressure of the negative oil chamber 3b is smaller than the pressure of the cooling oil passage 14, so the cooling oil passage A part of the cooling oil flowing through 14 flows into the negative oil chamber 3b. The cooling oil flowing into the negative oil chamber 3b is collected in the tank T2 through the negative line 32. Thereby, the air mixed in the hydraulic oil in the hydraulic circuit is effectively discharged to the outside of the hydraulic circuit. Further, the flow of the cooling oil from the cooling oil passage 14 toward the negative oil chamber 3b removes the foreign matter accumulated near the inner hole H2 and near the outer hole H1. The clogging of H2 and the outer hole H1 is suppressed.

When the piston 6 is arranged in the high pressure free communication range R221 of the free communication range R22, the pressure of the negative oil chamber 3b is higher than the pressure of the cooling oil passage 14, so that the negative oil chamber The hydraulic oil existing between 3b and the hydraulic pump 24 flows into the cooling oil passage 14 through the outer hole H1 and the inner hole H2 together with the air mixed in the hydraulic oil. The hydraulic oil and the air flowing into the cooling oil passage 14 are supplied to the clutch portion 4 together with the cooling oil flowing in the cooling oil passage 14, and then discharged from the clutch portion 4 to the outside and collected in the tank 37. .. Thereby, the air mixed in the hydraulic oil in the hydraulic circuit is effectively discharged to the outside of the hydraulic circuit.

When comparing the inconvenience caused by air mixing in the positive oil chamber 3a and the inconvenience caused by air mixing in the negative oil chamber 3b, the former has a higher degree of inconvenience. Therefore, the position where the outer hole H1 is provided in the outer pipe portion 61 of the piston 6 is the positive oil chamber 3a as shown in FIG. 3 rather than the position communicating with the negative oil chamber 3b as shown in FIG. It is preferable that the position communicates with.

[Other modifications]
The present invention is not limited to the embodiments described above. The present invention includes the following forms, for example.

(A) Regarding the movable range of the piston In the embodiment, the movable range includes the brake range R1 and the free range R2, and the free range R2 includes the free closed range R21 and the free communication range R22. Although the free communication range R22 includes the high pressure free communication range R221 and the low pressure free communication range R222, the movable range is not limited to the above embodiment. For example, the free range R2 may not include the free closed range R21, and may be composed of only the free communication range R22. Further, the free communication range R22 may be configured by only one of the high pressure free communication range R221 and the low pressure free communication range R222.

(B) Regarding Outer Hole and Inner Hole In the above-described embodiment, the outer hole H1 is provided only in the lower portion of the outer tube portion 61, and the inner hole H2 is provided only in the lower portion of the inner tube portion 13. However, it is not limited to these configurations. The outer hole H1 may be provided in a portion other than the lower portion of the outer pipe portion 61, for example, in an upper portion or a side portion of the outer pipe portion 61, and the inner hole H2 is a portion other than the lower portion of the inner pipe portion 13. For example, it may be provided on the upper portion or the side portion of the inner pipe portion 13.

Further, the outer pipe portion 61 may have a plurality of outer holes H1, and the inner pipe portion 13 may have a plurality of inner holes H2.

(C) Position where the winch drum is supported In the above-described embodiment, the case where the winch drum 1 is supported by the boom 104 is illustrated, but the position is not limited thereto. Even if the winch drum 1 is provided on the upper revolving structure 103, if the winch drum 1 is arranged near a member such as the gantry 107 (see FIG. 1) or a mast (not shown), the gantry 107 or When removing the mast from the upper revolving structure 103, it may be necessary to remove the winch drum 1 from the upper revolving structure for reasons such as space restrictions. Even in such a case, the winch device 10 and the crane 100 according to the above-described embodiment can be used.

(D) Throttle Portion In the above embodiment, the throttle portion 16 was provided in the inner pipe portion 13, but may be provided in the outer pipe portion 61. Further, the diaphragm unit 16 can be omitted.

(E) Regarding Pressure in Cooling Oil Passage In the above embodiment, the target value of the pressure in the cooling oil passage 14 is set to a constant value, but the present invention is not limited to this. The target value of the pressure in the cooling oil passage 14 may change based on a preset condition.

1 winch drum 3a positive oil chamber 3b negative oil chamber 4 clutch part 5 cylinder 6 piston 10 winch device 13 inner pipe part 14 cooling oil passage 16 throttle part 20 winch motor 22 mode switching valve 24 hydraulic pump (an example of hydraulic pressure source)
25a Operation pedal (an example of operation unit)
25b Brake control valve 61 Outer pipe part 100 Crane 101 Lower traveling body 103 Upper revolving structure 104 Boom H1 Outer hole H2 Inner hole R1 Brake range R2 Free range R21 Free block range R22 Free communication range R221 High pressure free communication range R222 Low pressure free communication range

Claims (7)

A winch device mounted on a crane,
A winch drum for winding or unwinding the rope,
A winch motor for rotating the winch drum,
A switching operation can be performed between a clutch-on state in which the power of the winch motor is transmitted to the winch drum and a clutch-off state in which the winch drum is separated from the winch motor to allow free rotation of the winch drum. With possible clutch part,
A cylinder,
An inner pipe part having a tubular oil pipe part having a cooling oil passage through which cooling oil for cooling the clutch part is disposed, and at least a part of the inner pipe part is arranged in the cylinder,
A piston that has an outer tube portion that surrounds the inner tube portion in the cylinder, and that axially moves relative to the cylinder and the inner tube portion within a predetermined movable range, and is positive together with the cylinder. A piston defining an oil chamber and a negative oil chamber,
The outer pipe portion of the piston has an outer hole that penetrates the outer pipe portion in the thickness direction thereof and communicates with one of the positive oil chamber and the negative oil chamber, the inner pipe portion, Having an inner hole that penetrates the inner pipe portion in its thickness direction and communicates with the cooling oil passage,
The movable range of the piston is a brake range in which the piston exerts a pressing force on the clutch portion so that the clutch portion is in the clutch on state, and the clutch portion is in the clutch off state. And a free range that is a range where the pressing force is released,
The outer hole is closed by the outer peripheral surface of the inner pipe portion when the piston is located in the brake range, and the piston is in the free communication range forming at least a part of the free range. When positioned, at least a part of the outer hole overlaps with the inner hole so that the one oil chamber and the cooling oil passage of the inner pipe portion communicate with each other through the outer hole and the inner hole. A winch device in which the relative position of the outer hole and the inner hole is set in the. The winch device according to claim 1,
A supply permissible position that is interposed between the one oil chamber and the hydraulic pressure source and that allows hydraulic oil discharged from the hydraulic pressure source to be supplied to the one oil chamber and the operation in the one oil chamber. A mode switching valve capable of switching to a discharge allowable position that allows oil to be discharged from the one oil chamber,
An operation unit that receives an operator's operation,
A brake control valve interposed between the hydraulic power source and the mode switching valve, the magnitude of the operation received by the operating portion when the mode switching valve is switched to the discharge allowable position. A brake control for adjusting the supply amount of the working oil supplied from the hydraulic pressure source to the one oil chamber according to the operation amount and arranging the piston at a position in the movable range according to the operation amount. A winch device further comprising a valve. The winch device according to claim 1 or 2, wherein
The winch device includes a high pressure free communication range that is a range in which the pressure in the one oil chamber corresponds to a pressure state higher than the pressure in the cooling oil passage. The winch device according to claim 3,
The winch device further includes a low pressure free communication range, which is a range corresponding to a pressure state in which a pressure in the one oil chamber is lower than a pressure in the cooling oil passage. The winch device according to any one of claims 1 to 4,
The free range further includes a free closing range in which the outer hole is closed by the outer peripheral surface of the inner tube portion,
The winch device, wherein the movable range of the piston is arranged in the axial direction in the order of the brake range, the free closing range, and the free communication range. The winch device according to any one of claims 1 to 5,
One of the outer pipe portion and the inner pipe portion has a throttle portion, and the throttle portion is a hole in the one pipe portion where the throttle portion is provided among the outer hole and the inner hole. The cross-sectional area of at least a part of the hole that defines at least a portion and is defined by the narrowed portion is larger than the cross-sectional area of the hole in the other pipe portion of the outer hole and the inner hole where the narrowed portion is not provided. A small, winch device. A crane,
Self-propelled undercarriage,
An upper revolving structure mounted on the lower traveling structure so as to be rotatable around an axis,
A winch device according to any one of claims 1 to 6;
The crane in which the winch drum of the winch device is configured to be attachable to and detachable from the upper swing body together with a part of a hydraulic circuit.

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