WO2018110606A1

WO2018110606A1 - Cargo platform lifting device

Info

Publication number: WO2018110606A1
Application number: PCT/JP2017/044760
Authority: WO
Inventors: 克弘堀川; 幹洋辻; 荘太片岡
Original assignee: 極東開発工業株式会社
Priority date: 2016-12-16
Filing date: 2017-12-13
Publication date: 2018-06-21

Abstract

The present invention addresses the problem of providing a cargo platform lifting device comprising a power unit that has an economically superior configuration. A valve block is connected to a hydraulic actuator and is made up of one main block 41 and at least one sub block 42. The main block 41 has incorporated therein a check valve 411 for preventing backflow of working fluid, a relief valve 412 for suppressing a working fluid overpressure state, a solenoid valve 413 that is opened when the hydraulic actuator contracts, and a main block fluid passage 414 that is connected to each of the valves. The at least one sub block 42 has incorporated therein at least one sub block fluid passage 421 connected to the main block fluid passage 414.

Description

Loading platform lifting device

Cross-reference of related applications

This application claims priority based on Japanese Patent Application No. 2016-244654 and Japanese Patent Application No. 2016-244656, and is incorporated herein by reference.

The present invention relates to a load receiving table lifting device mounted on a truck.

Conventionally, in a truck, a lifting platform lifting device mounted behind the loading platform is known. This load receiving device lifting device is disclosed in, for example, Japanese Patent No. 4823197 or Japanese Patent Application Laid-Open No. 58-12844.

2. Description of the Related Art A conventional load receiving table elevating device (for example, Japanese Patent No. 4823197) includes a hydraulically driven cylinder for raising and lowering a load receiving table and a power unit for supplying hydraulic oil to the cylinder.

However, the valve block with a built-in valve or the like in the conventional power unit is composed of a single block. For this reason, when changing or adding the function of the valve block according to the function required for the load receiving device lifting / lowering device, such as how to operate the lifting / lowering and storage of the load receiving device, the overall configuration of the valve block It was necessary to change to uneconomical.

Further, in a conventional load receiving table lifting device (for example, Japanese Patent Laid-Open No. 58-12844), when unloading, for example, the load receiving table is unfolded from the stowed state and lowered so as to be in contact with the ground from the loading table. Let The “ground” is not limited to a ground surface such as a road surface on which a lorry can travel, but also includes a surface having a height difference from the ground surface, such as a top surface of a concrete base. In other words, the entire surface on the ground side that can be contacted by the receiving platform during cargo handling is called “the ground”. The angle (tilt) of the load receiving platform is adjusted according to the positional relationship with the ground. The lifting and lowering of the load receiving table is performed by a hydraulically driven lift cylinder, and the unfolding and angle adjustment of the load receiving table are performed by a hydraulically driven tilt cylinder. The tilt cylinder is contracted by discharging the hydraulic oil when the load receiving platform is deployed and when the angle is adjusted to lower the rear of the load receiving platform.

However, in this conventional load receiving table lifting device, the operating speed is constant because the amount of hydraulic oil discharged in the contracting operation of the tilt cylinder is constant. For this reason, at the end of the contraction operation of the tilt cylinder, there is a possibility that the balance of the load on the load receiving platform will be lost due to the impact when the load receiving platform contacts the ground or the operation at a rapid speed, and the load will fall or fall over was there. For this reason, there was room for improvement.

Japanese Patent No. 4823197 (FIG. 5) Japanese Unexamined Patent Publication No. 58-12844 (Fig. 2)

Then, this invention makes it a subject to provide the load receiving stand raising / lowering apparatus provided with the power unit of the structure excellent economically.
Another object of the present invention is to provide a load receiving table lifting / lowering device capable of reducing the operation speed at the end of the contraction operation of the tilt cylinder.

The present invention is a load receiving table lifting device mounted on a truck, comprising: a load receiving table on which a load is placed; a hydraulic actuator that operates the load receiving table; and a power unit that supplies hydraulic oil to the hydraulic actuator. The power unit includes an oil feed pump that pumps hydraulic oil to the outside of the power unit, a drive unit that drives the oil pump, a tank that can store the hydraulic oil, a valve that controls oil flow, and the like. The valve block is connected to the hydraulic actuator and includes one main block and at least one sub-block, and the main block includes a check valve for preventing backflow of hydraulic oil. And a relief valve for suppressing the overpressure state of the hydraulic fluid, and when the hydraulic actuator contracts And at least one sub-block side connected to the main block-side oil passage is included in the at least one sub-block. An oil passage is incorporated, and the main block side oil passage includes a port connected to the oil feed pump, a port connected to the tank, and a port connected to the at least one sub block side oil passage. The at least one sub-block side oil passage includes a port connected to the main block and a port connected to the hydraulic actuator connected to the valve block. .

According to the above configuration, the function of the valve block can be changed by changing at least one sub-block combined with the main block into a sub-block having a different structure. Therefore, the main block can be shared between power units of different models. For this reason, the valve block can be formed by diverting the main block in the power unit of another model. Therefore, the man-hour for manufacturing a valve block can be reduced.

Still further, the main block can include a flow control valve for adjusting the oil amount in the middle of the oil passage reaching the tank via the solenoid valve in the main block side oil passage.

According to this configuration, the flow control valve can make the amount of oil during expansion and contraction constant for the hydraulic actuator. For this reason, even if the weight of the load placed on the load receiving table is different, the load receiving table can be operated at a constant speed.

Furthermore, the hydraulic actuator includes a hydraulically driven lift cylinder that raises and lowers the load cradle and a hydraulically driven tilt cylinder that adjusts an angle of the load cradle, and the at least one sub-block includes the lift actuator. A solenoid valve for passing oil through one or both of the cylinder and the tilt cylinder is incorporated, and the at least one sub-block side oil passage is connected to the port connected to the main block-side oil passage, and the lift cylinder A port to be connected and a port to be connected to the tilt cylinder can be provided.

According to this configuration, it is possible to configure a valve block suitable for a load receiving table lifting device that opens and closes the load receiving table by a tilt cylinder.

Still further, the power unit is disposed rearward of the axis of the rear wheel of the lorry, a front cover is provided in front of the power unit, and a solenoid valve provided in the valve block is provided on the valve block. It can be provided on the front side.

According to this configuration, the front cover can avoid collision of sand or mud wound up by the rear wheel with the solenoid valve. For this reason, the solenoid valve is unlikely to fail.

The present invention is also a load receiving table lifting device mounted on a truck, a load receiving table for placing a load, a hydraulically driven lift cylinder for moving the load receiving table up and down, and a hydraulic drive for adjusting an angle of the load receiving table. A tilt cylinder, and a power unit that supplies hydraulic oil to the lift cylinder and the tilt cylinder. The tilt cylinder is connected to the piston, a cylindrical cylinder tube, a piston that reciprocates in the cylinder tube, and the piston. A piston rod, a valve portion provided on the tip side of the piston so as to be movable in the axial direction of the piston rod, and a biasing portion for biasing the valve portion in the tip direction of the tilt cylinder. The cylinder tube is provided with a downstream oil passage on the tip side of the movable range of the piston, and the valve portion is provided with the downstream oil passage. Among them, it has a cross-sectional area larger than the cross-sectional area of the oil passing portion, and is configured to cover the piston so as to reduce the passing amount of hydraulic oil in the downstream oil passage before the piston reaches the tip of the movable range. It is a receiving platform lifting device.

According to the above configuration, before the piston reaches the tip of the movable range, the valve portion can be covered so as to reduce the passing amount of the hydraulic oil in the downstream oil passage. For this reason, the piston can be decelerated by reducing the amount of oil passing on the downstream side of the tilt cylinder. Therefore, the speed of the angle change of the load receiving platform can be reduced via the piston rod.

Still further, the piston rod includes a spindle that protrudes in the axial direction of the piston rod from a surface on the tip side, and the downstream oil passage is configured so that the piston rod reaches the tip of the movable range. A portion extending in the axial direction of the piston rod from the tip side surface of the piston rod, the spindle enters the downstream oil passage with the piston reaching the tip of the movable range, and the valve portion The spindle may pass through and may have a through hole having a cross-sectional area larger than the cross-sectional area of the spindle.

作動 According to this configuration, the hydraulic oil passes through the gap between the through hole of the valve portion and the spindle. For this reason, when the valve portion blocks the downstream oil passage, there is no need to separately form an oil passage for allowing the hydraulic oil having a reduced oil amount to pass therethrough.

Furthermore, the cylinder tube or the piston may be provided with a recess into which the valve portion enters in a state where the piston reaches the tip of the movable range.

According to this configuration, when the piston rod contracts and the piston reaches the tip of the movable range, the valve portion enters the recess. For this reason, it can prevent that a valve | bulb part is pinched | interposed into a piston and a cylinder tube, and is broken.

Still further, the biasing portion is a coil spring, the piston rod includes a protruding portion protruding from the piston toward the distal end side, and the coil spring is fitted into the protruding portion, and the proximal end side of the valve portion A spring support recess in which the coil spring tip is located can be formed.

According to this configuration, the coil spring as the urging portion is guided by the piston rod, and the position of the valve portion and the coil spring can be prevented from being shifted by the spring support recess. For this reason, it can be reliably operated without shifting the valve portion.

According to the present invention, the function of the valve block can be changed by changing at least one sub-block to a different structure. For this reason, a load receiving table lifting device including a power unit having an economically excellent configuration can be provided.
Moreover, according to this invention, the speed of the angle change of a load receiving stand can be reduced via a piston rod. Therefore, the operation speed can be reduced at the end of the contraction operation of the tilt cylinder. Therefore, it can suppress that the balance of the load on the load receiving stand is lost.

FIG. 1 is a schematic side view of a state in which each of the states of a cargo cradle is collectively shown, in which a cargo cradle lifting device according to an embodiment of the present invention is mounted on a truck. FIG. 2 is a side view showing the loading platform lifting device in the retracted state. FIG. 3 is a partial longitudinal sectional view showing the tilt cylinder. 4 is an enlarged view of a main part of FIG. FIG. 5A is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 5B is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 5C is a side view illustrating the change in posture of the load receiving table by the tilt cylinder in order. FIG. 5D is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 5E is a side view illustrating the change in posture of the load receiving table by the tilt cylinder in order. FIG. 5F is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 6A is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 6B is a side view illustrating the change in posture of the load receiving table by the tilt cylinder in order. FIG. 6C is a side view illustrating the change in posture of the load receiving table by the tilt cylinder in order. FIG. 6D is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 6E is a side view showing the change in posture of the load receiving table by the tilt cylinder in order. FIG. 6F is a side view illustrating the change in posture of the load receiving table by the tilt cylinder in order. FIG. 7 is an enlarged view of a main part of FIG. 6A. FIG. 8 is an enlarged view of a main part of FIG. 6B. FIG. 9 is an enlarged view of a main part of FIG. 6D. FIG. 10 is a plan view showing the arrangement of power units and the like in the cargo receiving platform lifting apparatus. FIG. 11A is a plan view showing the positional relationship between the power unit and the front cover. FIG. 11B is a diagram showing the positional relationship between the power unit and the front cover, as viewed from the vehicle rear side. FIG. 12 is a hydraulic circuit diagram of the power unit. FIG. 13 is a hydraulic circuit diagram of a power unit according to another embodiment.

Next, an embodiment of the present invention will be described. The vertical direction in the following description is the vertical direction on the paper surface of FIG. The front-rear and left-right directions correspond to the front-rear and left-right directions of the truck. That is, the left side in FIG. 1 is “front”, the right side is “back”, and the direction orthogonal to the plane of FIG. 1 is the left-right direction. And about the lift cylinder 2, it is a contraction side of a piston rod, Comprising: The side of the load receiving stand 1 in this embodiment is a "base end side", It is an expansion | extension side of a piston rod, Comprising: The lift frame 5 in this embodiment The side is the “tip side”. As for the tilt cylinder 3, it is the extension side of the piston rod 33, the load receiving platform 1 side in this embodiment is the “base end side”, the contraction side of the piston rod 33, and the lift frame 5 in this embodiment is The side is the “tip side”.

As shown in FIG. 1 (illustrated mounted state on the cargo vehicle T) and FIG. 2 (illustrated with the cargo table 1 and the

cylinders

2 and 3 extracted), the cargo receiving platform lifting / lowering device Pg of the present embodiment. A load receiving base 1 (also referred to as a “platform”) on which a load is placed and a hydraulic actuator for operating the load receiving base 1, and a hydraulically driven lift cylinder that moves the load receiving base 1 up and down 2, a hydraulically driven tilt cylinder 3 that adjusts the angle of the load receiving platform 1, and a power unit 4 (shown in FIG. 10) that supplies hydraulic oil to the lift cylinder 2 and the tilt cylinder 3. . Each

cylinder

2 and 3 is substantially cylindrical, and as shown in FIG. Each of the

cylinders

2 and 3 is configured to be able to expand and contract by allowing the piston rod to move in the axial direction with respect to the cylinder tube so that the cylinder rod can protrude and retract. The load receiving platform 1 is supported by a lift arm 6 that is rotatable with respect to a lift frame 5 fixed to the chassis of the lorry T, and is operated by the expansion and contraction of the

cylinders

2 and 3. Can do. The load receiving platform 1 is supported by a lift arm 6 via a rotating shaft 7. The load receiving platform 1 can be rotated with respect to the lorry T and the ground G such as the ground (tilt operation) by extending and retracting the tilt cylinder 3.

As shown in FIG. 1, the state of the loading platform 1 is as follows. For example, when unloading when the ground G is a horizontal plane, the loading platform 1 stands up with respect to the loading platform of the lorry T (state P1 / 2). It is rotated clockwise by 90 ° from the figure (shown by a dotted line) and developed 90 ° rearward, so that the upper surface 11 of the load receiving table is in a horizontal state (state P2). When the state P1 changes to the state P2, the tilt cylinder 3 contracts. In this state, the operator moves a load (not shown) from the loading platform to the loading platform 1. And the load receiving stand 1 descend | falls with the load receiving stand upper surface 11 in a horizontal state (state P3). This lowering stops in a state where a part of the load receiving platform 1 is in contact with the ground G (state P4). When the load receiving platform 1 is lowered, the lift cylinder 2 contracts. When the ground G is a horizontal plane, the rear portion of the load receiving platform 1 is not yet grounded in this state P4. Then, the angle of the load receiving platform 1 is adjusted according to the height and inclination of the ground G, and the rear portion of the load receiving platform 1 is grounded (state P5 / illustrated by a two-dot chain line). When the state P4 changes to the state P5, the tilt cylinder 3 contracts. In this state P5, the operator unloads the load on the ground G. When loading, it is the reverse of the above, that is, the operator moves the load from the ground G onto the load receiving platform 1 in the state P5, changes the angle of the load receiving platform 1 to the state P4, and changes from the state P4 to the load receiving platform. 1 changes to the rising state P2. When loading on the loading platform is completed, the state is set to P1, and the truck T can run. In the load receiving platform elevating device Pg of this embodiment, this operation is performed by an operator such as a driver of the truck T operating a switch of a controller (not shown).

When the load receiving platform 1 is raised and the load receiving platform 1 is rotated counterclockwise in FIG. 1, the

cylinders

2 and 3 are extended by being supplied with hydraulic fluid pressurized from the power unit 4. On the contrary, when the load receiving table 1 is lowered and the load receiving table 1 in FIG. 1 is rotated clockwise, the cap side provided on the cylinder cap (the portion indicated by 31A in the tilt cylinder 3 (see FIG. 3)). A port (which corresponds to the downstream oil passage outlet 3113 in the tilt cylinder 3) communicates with the tank 45 (see FIGS. 10 to 12). For this reason, each

cylinder

2, 3 moves the piston rod in the contracting direction mainly due to gravity applied to the load receiving platform 1, discharges the hydraulic oil from each

cylinder

2, 3, and the hydraulic oil flows out to the power unit 4. Shrink. In addition, at the moment when the load receiving platform 1 starts to fall from the state P1 shown in FIG. 1, since it is difficult for gravity to work in the direction of lowering the load receiving platform 1, the load receiving platform 1 is moved by the bias of the spring 37 provided inside the tilt cylinder 3. On the other hand, it causes the force to fall backward.

A stopper 12 protrudes upward at the rear part of the upper surface 11 of the cargo cradle 11 to prevent the luggage from sliding backward from the cradle 1. The stopper 12 is movable and can be stored in the cargo receiving platform 1.

Of the

cylinders

2 and 3, the tilt cylinder 3 has a built-in speed reduction mechanism 3s. Here, from the time immediately before the state P4 shown in FIG. 1 until the state P5 is reached, the conventional load receiving table elevating device operates at a constant speed. For this reason, there is a possibility that the balance of the load on the receiving platform 1 is lost and the load is dropped or falls. In the present embodiment, the possibility is suppressed by the speed reduction mechanism 3s. The deceleration mechanism 3s will be described below. The speed reduction mechanism 3s is provided in the tilt cylinder 3, but is not provided in the lift cylinder 2.

As shown in FIG. 3, the tilt cylinder 3 includes a cylindrical cylinder tube 31, a piston 32 that reciprocates in the cylinder tube 31, and a piston rod 33 that is coupled to the piston 32. FIG. 3 shows a state in which the tilt cylinder 3 is most contracted and the speed reduction mechanism 3s is working.

The cylinder tube 31 includes a cylinder cap 31A on the tip side. The cylinder tube 31 includes a downstream oil passage 311 on the tip side of the movable range of the piston 32. The cylinder tube 31 is provided with a recess 312 having a space for the valve portion 35 to enter in a state where the piston 32 reaches the tip of the movable range. The downstream oil passage 311 is an axis extending in the axial direction of the piston rod (the axial direction of the piston rod 33, the same applies hereinafter) from the surface on the distal end side of the piston rod 33 with the piston 32 reaching the distal end of the movable range. A directional oil passage 3111 and a radial oil passage 3112 extending in the radial direction from the distal end side of the axial oil passage 3111 and opening to the outer peripheral surface of the cylinder tube 31 are provided. The axial oil passage 3111 has a space in which a spindle 34 described later can enter.

The recess 312 of the present embodiment is formed such that the inner diameter of the proximal end portion of the axial oil passage 3111 is enlarged. The cross-sectional shape of the downstream oil passage 311 (including the recess 312) is circular. As shown in FIGS. 3 and 4, a later-described valve portion 35 and a protruding portion 331 of the piston rod 33 can enter the recess 312. The valve portion 35 is in contact with the inner surface 3121 on the distal end side in the recess 312. This contact prevents the hydraulic oil from passing between the tip surface of the valve portion 35 and the tip side inner surface 3121 of the recess 312. When the valve portion 35 enters the recess 312, the valve portion 35 can be prevented from being sandwiched between the piston 32 and the cylinder tube 31 and broken. Further, regarding the movable range of the piston 32, after the valve portion 35 abuts on the cylinder cap 31A of the cylinder tube 31, before the piston 32 abuts on the cylinder cap 31A (before the piston 32 reaches the tip of the movable range) 32 does not come into contact with the valve portion 35, and the movable range is not reduced by the presence of the valve portion 35. Therefore, the movable range of the piston 32 can be set to the maximum. For this reason, since the angle at the time of inclining the load receiving stand 1 can be taken large, the rear portion of the load receiving stand 1 can be grounded even if there is a distance between the ground G and the rear portion of the load receiving stand 1. In order to more reliably prevent the hydraulic oil from passing, a packing can be provided on the tip surface of the valve portion 35.

The piston rod 33 includes a spindle 34 that protrudes in the axial direction of the piston rod 33 from the tip side surface. The spindle 34 of the present embodiment is a round bar having a diameter smaller than that of the distal end portion of the piston rod 33, and the base end portion 341 is located at the distal end portion of the piston rod 33 so as to penetrate the piston 32. It is fixed by being screwed into. An enlarged portion 342 having an enlarged diameter is formed at the tip portion of the spindle 34 so that the valve portion 35 cannot be removed. The cross-sectional shape of the spindle 34 of this embodiment is circular. As shown in FIGS. 3 and 4, the spindle 34 enters the axial oil passage 3111 in the downstream oil passage 311 of the cylinder cap 31A with the piston 32 reaching the tip of the movable range.

The tilt cylinder 3 further includes a valve portion 35 provided on the tip side of the piston 32 so as to be movable in the axial direction of the piston rod 33, and a biasing portion 36 for biasing the valve portion 35 in the tip direction of the tilt cylinder 3. With. As shown in FIGS. 3 and 4, the valve portion 35 in the present embodiment is provided further on the distal end side than the surface on the distal end side of the piston 32.

The valve portion 35 has a cross-sectional area larger than the cross-sectional area of the oil passage portion in the axial oil passage 3111 in the downstream oil passage 311 in the cylinder tube 31. In the present embodiment, the “cross-sectional area of the oil passage portion” refers to the cross-sectional area of the spindle 34 (the portion where oil does not pass) when the spindle 34 enters the axial oil passage 3111 as shown in FIGS. Is the cross-sectional area at the inlet end of the axial oil passage 3111. The cross-sectional area of the spindle 34 may not be constant in the axial direction so that the enlarged portion 342 exists in the present embodiment, for example, but the “cross-sectional area of the oil passage portion” is the inlet end of the axial oil path 3111. It will be evaluated at. On the other hand, in the state where the spindle 34 does not enter the axial oil passage 3111, the “cross-sectional area of the oil passage portion” is the same cross-sectional area at the inlet end of the axial oil passage 3111. The valve part 35 of this embodiment is a disk-shaped body. The valve unit 35 is provided before the piston 32 reaches the front end of the movable range before the piston 32 reaches the front end of the movable range, specifically, after the valve unit 35 contacts the front end side inner surface 3121 in the recess 312. In the meantime, it is configured to cover the downstream oil passage 311 (axial oil passage 3111) so as to reduce the passing amount of hydraulic oil. For this purpose, the valve portion 35 is provided with a through hole 351 having a cross-sectional area (diameter dimension) larger than the cross-sectional area (diameter dimension) of the spindle 34 at the center in the radial direction. That is, the diameter of the outer edge of the cross-sectional shape of the valve portion 35 is larger than the diameter of the outer edge of the cross-sectional shape of the axial oil passage 3111. The diameter of the outer edge of the cross-sectional shape of the axial oil passage 3111 is larger than the diameter of the outer edge of the cross-sectional shape of the spindle 34 (part of the enlarged portion 342 in the present embodiment). The cross-sectional shape of the through hole 351 of the present embodiment is circular, and has a larger diameter than the diameter of the spindle 34 (the diameter of the portion excluding the enlarged portion 342). For this reason, a gap exists between the inner surface of the through hole 351 and the outer surface of the spindle 34. Even in a state where the valve portion 35 is in contact with the inner surface 3121 on the front end side in the recess 312 (that is, a state where most of the axial oil passage 3111 is closed), a small amount of hydraulic oil may pass through this gap. it can. That is, even in the contacted state, the inlet of the axial oil passage 3111 is maintained in a contracted state. Here, the “small amount” means that the amount of oil passing is smaller than that when the axial oil passage 3111 is opened.

The through hole 351 according to the present embodiment has both an effect of guiding the movement of the valve portion 35 in the axial direction by the spindle 34 and an effect of keeping the inlet of the axial oil passage 3111 in a contracted state. For this reason, the speed reduction mechanism 3s can be configured economically. Further, by forming the through hole 351 at the center in the radial direction of the valve portion 35, the valve portion 35 can be made rotationally symmetric, so that the valve portion 35 is easy to manufacture.

In the present embodiment, the biasing portion 36 is a coil spring that expands and contracts along the axial direction of the piston rod 33. By using the coil spring, it is possible to freely set the dimension in the axial direction in a free state (a state where the valve portion 35 is not in contact with the inner surface 3121 of the tip end side in the recess 312). Therefore, by appropriately selecting the length of the spindle 34 and the dimension of the urging portion (coil spring) 36 in the free state, the axial movement range of the valve portion 35, that is, the range in which the speed reduction mechanism 3s operates can be freely set. Can be set.

Here, the piston rod 33 is provided with a protruding portion 331 protruding from the piston 32 toward the tip side. The protruding portion 331 of this embodiment is cylindrical, and an urging portion (coil spring) 36 is fitted to the protruding portion 331. As shown in FIGS. 3 and 4, the protrusion 331 enters the recess 312 when the piston 32 reaches the tip of the movable range. Further, a spring support recess 352 in which the distal end portion of the biasing portion (coil spring) 36 is located is formed on the proximal end side of the valve portion 35. With this configuration, the urging portion (coil spring) 36 is guided in the axial direction by the protruding portion 331 of the piston rod 33, and the valve portion 35 and the urging portion (coil spring) are formed by the spring support recess 352. The position in the radial direction with respect to 36 can be prevented from shifting. For this reason, the valve portion 35 can be reliably operated without shifting. In particular, by using a coil spring as the urging portion 36 as in the present embodiment, since this coil spring has a cylindrical space inside, the protruding portion 331 of the piston rod 33 is urged ( Easy to insert into the coil spring 36. However, the present invention is not limited to this configuration, and for example, a guide member separate from the piston rod 33 is provided, or a guide member is not provided inside the coil spring that is the urging portion 36, and the guide member is expanded and contracted without any guide. You may comprise.

In the present embodiment, the axial oil passage 3111 of the downstream oil passage 311, the spindle 34, and the central portion of the valve portion 35 coincide with each other and are on the central axis of the piston rod 33. For this reason, even if the piston 32 and the piston rod 33 are displaced in the rotational direction when the piston 32 contracts, the spindle 34 enters the axial oil passage 3111 and the valve portion 35 covers the inlet of the axial oil passage 3111. Is made stable.

As described above, the speed reduction mechanism 3 s included in the tilt cylinder 3 includes the downstream oil passage 311 (axial oil passage 3111), the recess 312, the protruding portion 331 of the piston rod 33, the spindle 34, the valve portion 35, and the biasing portion 36. ing. Next, the operation accompanying the contraction of the tilt cylinder 3 of the deceleration mechanism 3s will be described.

FIG. 5A to FIG. 5F and FIG. 6A to FIG. 6F show a process of developing the receiving platform 1. 5 and FIG. 6 differ in the angle of the load receiving platform 1 due to the degree of expansion / contraction of the lift cylinder 2 being different. FIG. 5 shows a case where the surface of the lorry T where the wheel is grounded and the ground G, which is the surface where the cargo cradle 1 is lowered, are at the same height, and FIG. 6 shows that the wheel of the lorry T is grounded. The case where the ground G which is the surface which lowers the receiving stand 1 is in a higher position than the surface which is carrying out is shown. Incidentally, FIG. 6A shows a state in which the cargo vehicle T is stored, and the cargo vehicle T can travel.

FIG. 5A and FIG. 6A show an initial state that is the extension side stroke end (most extended) of the tilt cylinder 3. 5B, FIG. 5C, FIG. 6B, and FIG. In the state of FIGS. 5A to 5C and FIGS. 6A to 6C, the hydraulic oil is discharged from the tilt cylinder 3 mainly due to gravity applied to the load receiving platform 1 and the hydraulic oil flows out to the power unit 4 so that the tilt cylinder 3 contracts. . Up to this point, as shown in FIG. 7 (enlarged view of FIG. 6A) and FIG. 8 (enlarged view of FIG. 6B), the valve portion 35 and the recessed portion 312 are separated from each other, so that no deceleration is performed. 5D and 6D show the moment when deceleration is started. In this embodiment, as shown in FIG. 9 (enlarged view of FIG. 6D) when the angle of the upper surface 11 of the load receiving table 11 rises to 3 ° (before 3 ° when the load receiving table 1 becomes horizontal). The valve portion 35 comes into contact with the inner surface 3121 (see FIG. 4) on the front end side in the recess 312. As a result of this contact, the hydraulic oil that is about to flow out of the tilt cylinder 3 due to gravity passes only through the gap between the inner surface of the through hole 351 (see FIG. 4) and the outer surface of the spindle 34 in the valve portion 35. Become. For this reason, the contraction speed of the tilt cylinder 3 is reduced by reducing the amount of oil flowing out from the tilt cylinder 3. FIG. 5E and FIG. 6E show a state where the upper surface 11 of the cargo receiving table is horizontal. Then, when the rear portion of the load receiving platform 1 comes into contact with the ground G until the load receiving table upper surface 11 is tilted rearward and reaches the state shown in FIGS. 5F and 6F, the unfolding operation is stopped at that point (this time) In the embodiment, it is stopped by an operator's switch operation). In this state, the tilt cylinder 3 is further contracted, and the urging portion 36 is shortened while the valve portion 35 is in contact with the tip side inner surface 3121 of the recess 312. For this reason, deceleration is continued. 5F and FIG. 6F show the final state that is the contraction side stroke end of the tilt cylinder 3 (the tilt cylinder 3 is most contracted). The speed reduction mechanism 3s is in the state shown in FIG. In this state, the load receiving table upper surface 11 is inclined backward. For example, when the lorry T is stopped in the middle of the downhill and the cargo handling work is performed on the uphill side, the cargo receiving table upper surface 11 can be made horizontal in this state. In this state, the urging portion 36 is in the most shortened state while the valve portion 35 is in contact with the inner surface 3121 on the distal end side in the recess 312.

Through the above process, before the piston 32 reaches the tip of the movable range, the valve portion 35 can be covered so as to reduce the amount of hydraulic oil passing through the downstream oil passage 311. With the piston 32 reaching the tip of the movable range, the spindle 34 enters the axial oil passage 3111 of the downstream oil passage 311. For this reason, at the contraction side stroke end of the tilt cylinder 3, the valve portion 35 can always reduce the passage of hydraulic oil. Note that the timing of the start of the decrease in the passage of hydraulic oil (that is, the time when the valve unit 35 covers the downstream oil passage 311) depends on the timing at which the spindle 34 starts to enter the axial oil passage 3111 of the downstream oil passage 311. Can be adjusted.

In this way, the piston 32 can be decelerated by reducing the amount of oil passing on the downstream side of the tilt cylinder 3. Therefore, the speed of the angle change of the load receiving platform 1 can be reduced via the piston rod 33. As a result, at the end of the contraction operation of the tilt cylinder 3, the impact speed when the load receiving platform 1 touches the ground G and the rapid speed at the start of the operation when tilting the load receiving platform upper surface 11 from the horizontal state to lower the load. It is possible to suppress the operation with. For this reason, since the balance of the load on the load receiving stand 1 can be prevented from falling and the load falling, the cargo handling operation can be performed safely. Note that the tilt cylinder 3 may stop operating until reaching the stroke end. In this case, if the spindle 34 has entered the axial oil passage 3111 of the downstream oil passage 311 at the time of stopping, the piston 32 can be decelerated as described above.

It should be noted that the same effect can be obtained even when the electrical control is performed so as to reduce the oil amount at the end of the contraction operation of the tilt cylinder 3. However, in the present embodiment, since the speed reduction mechanism 3s is provided in the tilt cylinder 3, it is not particularly necessary to deal with the control surface. Therefore, for example, there is a merit that the control program of the load receiving platform elevating device Pg can be simplified. Moreover, since the sensor for detecting the horizontal state of the load receiving table upper surface 11 in the load receiving table 1 is not required, the structure of the load receiving table lifting / lowering device Pg can be simplified and inexpensive.

In the configuration of the present embodiment, the hydraulic oil passes through the gap between the through hole 351 of the valve unit 35 and the spindle 34. For this reason, when the valve part 35 blocks the downstream oil passage 311, it is not necessary to separately form an oil passage for allowing the hydraulic oil to pass with a reduced passage amount. Therefore, the structure of the tilt cylinder 3 provided with the speed reduction mechanism 3s can be simplified.

Next, the power unit 4 will be described. As shown in FIG. 10 to FIG. 12, the power unit 4 of the present embodiment mainly includes a main block 41 and a sub block 42 that can be configured by combining valve blocks that incorporate valves and the like that control oil passage, and operation. An oil feed pump 43 that pumps oil to the outside of the power unit 4 (main block 41 and sub-block 42 in the present embodiment), a motor 44 that is a driving means for driving the oil feed pump 43, a tank 45 that can store hydraulic oil, an oil A filter 46 is provided. In the present embodiment, the driving means is an electric motor 44, but is not limited to this. For example, the driving means may be a means for taking in a driving force from the outside of the power unit 4 to change the speed.

The power unit 4 is fixed on a bracket 51 that extends to the rear of the lift frame 5. In the present embodiment, the power unit 4 is disposed behind the rear wheel axis Rc (see FIG. 1) of the lorry T.

The arrangement of the portions appearing in the appearance of the power unit 4 is as shown in FIG. 10, FIG. 11A, and FIG. 11B. The main block 41 is disposed vertically on the bracket 51 in the direction when viewed from the rear (the direction orthogonal to the paper surface in FIG. 11B), the sub-block 42 is disposed thereon, and the motor 44 is disposed to the left of the main block 41. A tank 45 is arranged on the right side. In addition, an oil feed pump 43 is disposed on the right side of the main block 41 and an oil filter 46 is disposed on the right side. In addition, arrangement | positioning of each element which comprises the power unit 4 is not limited to the thing of this embodiment, It can arrange | position with a various pattern.

In this embodiment, the upper end position of the motor 44 is lower than the upper end position of the tank 45 as shown in FIG. 11B. The sub block 42 is located above the motor 44 so that the upper end of the sub block 42 does not protrude from the upper end position of the tank 45. By arranging the sub-block 42 in this way, the vertical dimension of the power unit 4 can be made compact, and the cover 8 can also be miniaturized.

In the main block 41, the solenoid part 41s is positioned so as to protrude forward. In the sub-block 42, the

solenoid portions

42s and 42s are positioned so as to protrude to the left.

Further, as shown in FIGS. 10, 11A, and 11B, the power unit 4 is covered with a hollow, substantially rectangular parallelepiped cover 8 in the front, rear, left, and right directions (only the front cover 81 is shown in FIGS. 11A and 11B). ). The cover 8 is formed from a plate-like body and is assembled by bolts. For this reason, the power unit 4 can be exposed by being removed during maintenance of the power unit 4. Although not shown, the cover 8 can be provided with a ventilation opening for cooling the motor 44 and the like.

In the main block 41, a check valve 411 for preventing backflow of hydraulic oil in the direction toward the port 4143 and an overpressure state of the hydraulic oil in the entire hydraulic circuit are suppressed, so that the main block 41 is opened when a predetermined pressure is exceeded. The relief valve 412, the solenoid valve 413 that is opened when the cylinders (the lift cylinder 2 and the tilt cylinder 3 in this embodiment) connected to the valve block contract, and the main block side that is connected to each of the valves 411 to 413 An oil passage 414 is incorporated. As the solenoid valve 413 of this embodiment, a 2-port 2-position switching type solenoid valve is used (however, the configuration of the solenoid valve is not limited to this). The main block side oil passage 414 includes a port 4141 connected to the oil feed pump 43, a port 4142 connected to the tank 45, and

ports

4143 and 4144 connected to the sub block side oil passage 421 of the sub block 42. Prepare. Each port 4141 to 4144 is formed in a shape that allows connection of a pipe joint as required.

The main block 41 is in the middle of an oil passage that reaches the tank 45 via the solenoid valve 413 in the main block-side oil passage 414 (the hydraulic oil that returns from the

cylinders

2 and 3 to the tank 45 flows in this oil passage). In the embodiment, a flow control valve 415 for adjusting the oil amount is provided on the downstream side (left side in FIG. 12) when the solenoid valve 413 is oiled. With this flow control valve 415, the amount of oil when contracted with respect to the lift cylinder 2 can be made constant. For this reason, even if the weight of the load placed on the load receiving platform 1 is different, the load receiving platform 1 can be lowered at a constant speed. In the present embodiment, the same applies to the tilt cylinder 3, and the oil amount during contraction can be made constant by the flow control valve 415. Therefore, the load receiving platform 1 can be rotated at a constant speed. A filter 416 is provided between the solenoid valve 413 and the flow control valve 415. Note that the flow control valve 415 and the filter 416 are not essential and may be omitted.

The main block side oil passage 414 includes a first upper and lower oil passage 4145 that connects the

ports

4141 and 4143 and extends up and down, a second upper and lower oil passage 4146 that connects the

ports

4142 and 4144 and extends up and down, a first upper and lower oil passage 4145 Two upper and lower oil passages 4146 are connected to each other and extend to the left and right in the drawing. The first upper and lower oil passages 4147 and the left and right oil passages 4147 where the solenoid valve 413, the flow control valve 415, and the filter 416 are located The oil passage 4145 and the second upper and lower oil passage 4146 are connected to each other and extend to the left and right in the drawing, and is composed of a second left and right oil passage 4148 in which the relief valve 412 is located. The check valve 411 is located between the branch portion of the first left and right oil passage 4147 and the branch portion of the second left and right oil passage 4148 in the first upper and lower oil passage 4145.

The sub block 42 is connected above the main block 41. The sub block 42 incorporates at least a sub block side oil passage 421 connected to the main block side oil passage 414 of the main block 41. The sub-block side oil passage 421 includes

ports

4211 and 4212 connected to the main block 41, and

ports

4213 and 4214 connected to the lift cylinder 2 and the tilt cylinder 3, respectively. Each port 4211 to 4244 is formed in a shape that allows connection of a pipe joint as required.

The sub-block 42 of the present embodiment further incorporates

solenoid valves

422 and 423 for passing oil through one or both of the lift cylinder 2 and the tilt cylinder 3.

Filters

424 and 425 are provided below the solenoid valves 422 and 423 (on the oil feed pump 43 side when oil is passed).

The sub-block-side oil passage 421 branches from the gathering oil passage 4215 positioned directly above the port 4211 and the gathering oil passage 4215 to pass through the lift cylinder 2 and extends to the port 4213, and includes the solenoid valve 422 and the filter 424. The oil passage 4216 for the lift is located, branches from the collecting oil passage 4215 so as to pass through the tilt cylinder 3, and extends to the port 4214. The oil passage 4217 for the tilt where the solenoid valve 423 and the filter 425 are located, the oil for the tilt The self-lubricating passage 4218 is branched from the passage 4217 and extends to the lower port 4212. A self-lubricating passage 4218 is provided with a check valve 426 for preventing backflow in the direction toward the port 4212.

Note that, depending on the model of the load receiving platform lifting / lowering device Pg, a tilt operation, which is an operation of rotating the load receiving platform 1 with respect to the ground vehicle G and the ground G such as the ground, is performed manually without using the tilt cylinder 3. There is something. In this case (when the load receiving platform 1 is manually rotated), it is not necessary to provide the tilt oil passage 4217, the self-supply oil passage 4218, the solenoid valve 423, and the filter 425 in the sub-block 42.

Further, the self-supply oil passage 4218 is an oil for sending hydraulic oil to the tilt cylinder 3 when the load receiver 1 is manually rotated to store the load receiver 1 from the unfolded state in the configuration including the tilt cylinder 3. Road. Due to the self-lubricating passage 4218, the side where the piston rod 33 does not exist (the side of the cylinder cap 31A) in the tilt cylinder 3 is in a vacuum state, and the next time the load receiving platform 1 is deployed (the tilt cylinder 3 contracts). When the piston rod 33 is suddenly moved in the contraction direction, it is possible to prevent the load receiving platform 1 from being suddenly rotated in the deployment direction. In the case where such manual operation is not performed, the self-lubricating passage 4218 can be omitted. In this case, the port 4144 in the main block 41 and the section of the second upper and lower oil passages 4146 to the branch portion of the first left and right oil passages 4147 are also functionally unnecessary. However, from the viewpoint of sharing the main block 41, in the present embodiment, the unnecessary portion is left provided in the main block 41 in a state where the port 4144 is closed so that the hydraulic oil does not leak. . As a result, the main block 41 can be shared.

With the above configuration, it is possible to configure a valve block suitable for a load receiving table lifting device of the type that opens and closes the load receiving table 1 with the tilt cylinder 3 and changes the angle (tilt).

The main block 41 and the sub-block 42 have the main body portions 41m and 42m formed in a substantially rectangular parallelepiped block shape. However, the

solenoid parts

41s and 42s in the valve block of the present embodiment protrude from the main body parts 41m and 42m, respectively. The main block 41 and the sub-block 42 are used with their outer surfaces in contact with each other. At the time of this connection, the

ports

4143, 4211/4144, and 4212 located at the connection portion between them are also connected. In this embodiment, the connection is made by a bolt, but the connection means is not particularly limited.

Thus, the main block 41 and the sub-block 42 are configured to be connectable and detachable. For this reason, the sub-block 42 combined with the main block 41 can be changed to a sub-block 42 having a different structure. As a result, the function of the valve block can be easily changed. Therefore, at least two different types of power units 4 of the hydraulic mechanism are gathered in the main block 41, and the essential parts are added to the sub block 42 in the hydraulic mechanism. By concentrating general parts, that is, by sharing the function between the main block 41 and the sub-block 42, the configuration of the valve block can be diversified while the main block 41 is shared. That is, when the valve block is manufactured, for example, if there is surplus stock in the main block 41 for other models, the main block 41 can be used to reduce the number of steps compared to manufacturing the entire valve block from the beginning. . For this reason, a freedom degree can be raised about the function of a valve block, and valve block arrangement | positioning to the lorry T. And it can contribute to the manufacturing cost reduction of the power unit 4. FIG.

A front cover 81 is provided as a part of the cover 8 in front of the power unit 4 in the present embodiment. At least a part of the solenoid valve provided in the valve block (the solenoid portion 41s in the main block 41 in the present embodiment) is provided on the front side of the valve block (the main block 41 and the sub block 42). According to this configuration, since the solenoid valve is positioned immediately after the front cover 81, the front cover 81 can avoid collision of sand and mud wound up by the rear wheel with the solenoid valve, and the solenoid valve is unlikely to break down. . This is very advantageous in a lorry T that often runs on an unpaved road.

As mentioned above, although one embodiment was taken up and explained per the present invention, the present invention is not limited to the above-mentioned embodiment. For example, the hydraulic actuator is not limited to the hydraulically driven cylinder as in the above embodiment, and may be a hydraulic motor. In addition, the valve portion 35 can be supported only by the urging portion 36 without providing the spindle 34. Specifically, one end of the urging portion 36 can be connected to the piston 32 or the piston rod 33, and the other end of the urging portion 36 can be connected to the valve portion 35. In addition, although the spindle 34 of the above embodiment is separate from the piston rod 33, the spindle 34 can be formed as a part of the piston rod 33. Moreover, in the said embodiment, although the protrusion part 331 of the piston rod 33 penetrated the piston 32 and protruded to the front end side, it can also be prevented from penetrating or protruding. In this case, the protruding portion 331 can be formed as a part of the piston 32, or can be formed of another member (such as a bar) different from the piston 32 and the piston rod 33. With the protruding portion 331 thus formed, The urging portion 36 can be guided in the axial direction.

Further, the cross-sectional shapes of the downstream oil passage 311, the spindle 34, and the valve portion 35 are not limited to a circle, and may be a polygon. In this case, the cross-sectional outer edge of the valve portion 35 may not be in a relationship covering the entire cross-sectional outer edge of the downstream oil passage 311. In short, it is only necessary that when the valve portion 35 covers the downstream oil passage 311, the amount of oil passing through can be reduced so that the piston 32 can be decelerated.

Further, in the valve portion 35, another through hole through which a small amount of hydraulic oil is exclusively passed may be provided at a position different from the through hole 351 and the spindle 34. Further, the valve portion 35 is not provided with a through hole through which hydraulic oil can pass, and a bypass oil passage that passes through the inside and outside of the cylinder tube 31 is opened at a position that is not covered by the valve portion 35, such as the inner surface of the recess 312 Further, the bypass oil passage can be configured not to be blocked by the valve portion 35 by connecting the recess 312 and the axial oil passage 3111 at positions outside the diameter of both. Then, a small amount of hydraulic oil can be passed through this bypass oil passage. When the bypass oil passage is provided in this way, the through hole 351 of the valve portion 35 is not essential. For example, when the spindle 34 is provided, the dimension of the through hole 351 can be set to a minimum dimension that allows the valve portion 35 to move with respect to the spindle 34 so that the hydraulic oil does not pass through the through hole 351. Further, when the spindle 34 is not provided, the through hole 351 can be prevented from being formed. Further, the concave portion 312 into which the valve portion 35 enters is provided in the cylinder tube 31 in the embodiment. However, the present invention is not limited to this, and a recess can be provided in the piston 32. In this case, the valve portion 35 is provided on the distal end side with respect to the proximal end side of the concave portion provided in the piston 32.

Further, in the above-described embodiment, it is set so that the deceleration is started from 3 ° before the loading platform 1 becomes horizontal when the loading platform 1 is deployed. However, the angle at which deceleration is started can be set to another angle by changing the position of the valve portion 35 with respect to the piston rod 33 in the free state of the urging portion 36.

Further, although the speed reduction mechanism 3s of the above embodiment is configured to decelerate when contracted, it can also be configured to decelerate when expanded. Further, the lift cylinder 2 may be provided with a speed reduction mechanism similar to that of the above embodiment.

Also, the load receiving platform lifting / lowering device Pg may be a model having only the lift cylinder 2 without the tilt cylinder 3.

Alternatively, the load receiving platform 1 may be configured to be foldable at an intermediate portion in the front-rear direction, and the intermediate portion may be folded and unfolded by a hydraulic actuator. In this case, the hydraulic actuator corresponds to the “hydraulic actuator that operates the load receiving table 1”.

Also, a load receiving platform lifting / lowering device that includes a slide cylinder (not shown) as a hydraulic actuator for operating the load receiving platform 1 for moving the load receiving table 1 in the longitudinal direction of the vehicle and that can store the load receiving table 1 under the floor of the truck T. The present invention can also be applied to Pg models. An example of the hydraulic circuit in this case is shown in FIG. The configuration of the main block 41 is the same as that in the embodiment (see FIG. 12). In the present embodiment, the sub-block 47 includes a solenoid valve 472 for passing oil through the lift cylinder 2, a solenoid valve 473 that is excited when the slide cylinder is extended, and a solenoid valve 474 that is excited when the slide cylinder is contracted. Has been.

Filters

475, 476, and 477 are provided below the solenoid valve 472, to the right of the solenoid valve 473, and above the solenoid valve 474, respectively.

The sub-block side oil passage 471 branches from the collective oil passage 471f to pass through the lift cylinder 2 and extends to the port 471c, and extends to the port 471c. The sub-block side oil passage 471 extends to the port 471c. The lift oil passage 471g in which the valve is located is branched from the collective oil passage 471f to pass through the slide cylinder and extends to the

ports

471d and 471e, and the slide expansion / contraction oil passage 471h in which the check valve 479 and the flow control valve 480 are located. , A slide contraction oil passage 471i extending up and down connecting the

ports

471b and 471d, a slide extension oil passage 471h connecting the slide contraction oil passage 471h and the slide contraction oil passage 471i and extending in the left and right directions in the drawing. ing. The slide contraction oil passage 471i is provided with a check valve 478 for preventing a reverse flow toward the port 471b, and the slide expansion / contraction oil passage 471h is provided with a check valve 479 for preventing a reverse flow in the

ports

471a and 471e. It has been. When the main block 41 and the sub-block 47 are connected, the

ports

4143, 471a / 4144, 471b located at the connection portion between them are connected. As described above, even if the sub block 47 is changed, it is not necessary to newly provide an oil passage or a valve in the main block 41, and the main block 41 can be shared.

In the embodiment, one main block 41 and one sub block 42 are used, but a valve block may be configured by connecting two or more sub blocks 42 to one main block 41. .

Also, the sub-block 42 can be provided with only an oil passage and a port without any valves or filters.

In the above embodiment, the number of ports for connecting the sub-block 42 in the main block 41 is two (ports 4143 and 4144). However, the number of ports is not limited to this, and the number of ports may be three or more.

Further, the number of ports for connecting the main block 41 in the sub block 42 may be smaller than the number of ports for connecting the sub block 42 of the main block 41. In this case, ports that are not used to connect the sub-block 42 in the main block 41 are closed by attaching a plug or the like.

Further, in the above-described embodiment, regarding the

solenoid valves

422, 423, 472, 473, and 474 in the sub-blocks 42 and 47, two-port two-position switching type solenoid valves are respectively provided in the oil passages for passing oil through the cylinders. It was done. However, the configuration of the solenoid valve is not limited to this, and may be, for example, a switching type solenoid valve having three ports or more and three positions or more. Further, it may be a solenoid valve that only allows oil to pass through any one of the lift cylinder 2, the tilt cylinder 3, and the slide cylinder. Further, it may be a solenoid valve that allows oil to pass through one or more of the lift cylinder 2, the tilt cylinder 3, and the slide cylinder. Furthermore, a mechanism for blocking oil flow to each cylinder can be added to these solenoid valves.

DESCRIPTION OF SYMBOLS 1 Loading stand 2 Hydraulic actuator, lift cylinder 3 Hydraulic actuator, tilt cylinder 31 Cylinder tube 311 Downstream side oil path 3111 A part extended in an axial direction among downstream side oil paths, Axial direction oil path 312 Recessed part 32 Piston 33 Piston rod 331 Protrusion part 34 Spindle 35 Valve portion 351 Through hole 352 Spring support recess 36 Energizing portion 3s Reduction mechanism 4 Power unit 41 Valve block (main block)
411 Check valve 412 Relief valve 413 Solenoid valve 414 Main block side oil passage 4141 Port connected to

oil feed pump

4143, 4144 Port connected to sub block side oil passage 415 Flow control valve 42 Valve block (sub block)
421 Sub-block

side oil passages

4211, 4212 Port connected to main block 4213 Port connected to lift cylinder 4214 Port connected to tilt

cylinder

422, 423 Solenoid valve 43 Oil feed pump 44 Drive means, motor 45 Tank 8 Cover 81 Front cover Pg Cargo stand lifting device T Lorry Rc Lorry rear axle

Claims

A load receiving table lifting device mounted on a truck, comprising: a load receiving table on which a load is placed; a hydraulic actuator that operates the load receiving table; and a power unit that supplies hydraulic oil to the hydraulic actuator,
The power unit includes an oil feed pump that pumps hydraulic oil to the outside of the power unit, a drive unit that drives the oil pump, a tank that can store the hydraulic oil, a valve block that incorporates a valve that controls oil flow, and the like. And
The valve block is connected to the hydraulic actuator and includes one main block and at least one sub block.
The main block includes a check valve for preventing backflow of hydraulic oil, a relief valve for suppressing an overpressure state of hydraulic oil, a solenoid valve that is opened when the hydraulic actuator contracts, The main block side oil passage connected to each valve is built-in,
The at least one sub block includes at least one sub block side oil passage connected to the main block side oil passage,
The main block side oil passage includes a port connected to the oil feeding pump, a port connected to the tank, and a port connected to the at least one sub block side oil passage,
The at least one sub-block-side oil passage includes a port connected to the main block and a port connected to the hydraulic actuator connected to the valve block.
The said main block is provided with the flow control valve for adjusting the oil quantity in the middle of the oil path which reaches the said tank via the said solenoid valve among the said main block side oil paths, The load receiving stand of Claim 1 lift device.
The hydraulic actuator includes a hydraulically driven lift cylinder that raises and lowers the cargo cradle, and a hydraulically driven tilt cylinder that adjusts the angle of the cargo cradle,
The at least one sub-block has a built-in solenoid valve for passing oil through one or both of the lift cylinder and the tilt cylinder,
The at least one sub-block side oil passage includes a port connected to the main block-side oil passage, a port connected to the lift cylinder, and a port connected to the tilt cylinder. Or the load receiving table raising / lowering device of 2.
The power unit is disposed behind the axis of the rear wheel of the truck,
A front cover is provided in front of the power unit,
The load receiving platform lifting apparatus according to any one of claims 1 to 3, wherein the solenoid valve provided in the valve block is provided in front of the valve block.
A load receiving table lifting device mounted on a lorry, a load receiving table on which a load is placed, a hydraulically driven lift cylinder that lifts and lowers the load receiving table, a hydraulically driven tilt cylinder that adjusts an angle of the load receiving table, A power unit for supplying hydraulic oil to the lift cylinder and the tilt cylinder,
The tilt cylinder has a cylindrical cylinder tube, a piston that reciprocates in the cylinder tube, a piston rod that is coupled to the piston, and is movable in the axial direction of the piston rod closer to the tip than the piston. A provided valve portion, and a biasing portion that biases the valve portion toward the tip of the tilt cylinder,
The cylinder tube includes a downstream oil passage on the tip side of the movable range of the piston,
The valve portion has a cross-sectional area larger than the cross-sectional area of the oil passage portion in the downstream oil passage, and before the piston reaches the tip of the movable range, the hydraulic oil in the downstream oil passage A load receiving table elevating device configured to cover so as to reduce a passing amount.
The piston rod includes a spindle that protrudes in the axial direction of the piston rod from a surface on the tip side,
The downstream oil passage has a portion extending in the axial direction of the piston rod from the surface on the tip side of the piston rod in a state where the piston reaches the tip of the movable range,
The spindle enters the downstream oil passage with the piston reaching the tip of the movable range,
6. The load receiving platform lifting device according to claim 5, wherein the valve portion includes a through-hole through which the spindle passes and having a cross-sectional area larger than a cross-sectional area of the spindle.
The load receiving platform lifting device according to claim 5 or 6, wherein the cylinder tube or the piston is provided with a recess into which the valve portion enters in a state where the piston reaches the tip of the movable range.
The biasing portion is a coil spring;
The piston rod includes a protruding portion protruding from the piston toward the tip side, and the coil spring is fitted to the protruding portion,
The load receiving platform lifting apparatus according to any one of claims 5 to 7, wherein a spring support recess in which a distal end portion of the coil spring is located is formed on a proximal end side of the valve portion.