JP7066451B2 - Concrete pump - Google Patents

Description

The present invention is used when placing ready-mixed concrete in a building or the like, and relates to a concrete pump for extruding ready-mixed concrete.

Conventionally, as a technique related to a concrete pump, for example, there is one described in Patent Document 1. Patent Document 1 describes the configuration of a hydraulic cylinder in a concrete pump as a conventional example. As shown in FIG. 5, the hydraulic cylinder 50 described here is provided with a piston 52 and a cylinder rod 53 that reciprocate inside the cylinder tube 51, and further, a sensor rod extending in the longitudinal direction is provided inside the cylinder tube 51. 54 is fixed on one end side. The piston 52 and the cylinder rod 53 are hollow in the radial center, and the sensor rod 54 is located in the hollow portion. Further, a magnet 55 is provided inside the piston 52 at a position facing the outer peripheral surface of the sensor rod 54. A pipe material is used as the sensor rod 54, and a magnetic sensor 56 is provided inside the sensor rod 54.

In this hydraulic cylinder 50, when the piston 52 moves, the piston 52 moves with respect to the sensor rod 54, so that the magnetic sensor 56 detects a change in the magnetic field due to the magnet 55 provided on the piston 52. This makes it possible to measure the position of the piston 52 in the hydraulic cylinder 50.

Jitsukaihei No. 2-18662

Since the sensor rod 54 having the above configuration is fixed to the cylinder tube 51 only on one end side, bending (bending) may occur. When the piston 52 and the cylinder rod 53 move in a state where the sensor rod 54 is bent, the inner surface of the hollow portion of the piston 52 and the cylinder rod rod 53 may come into contact with the sensor rod 54. If such contact is repeated, the sensor rod 54 will be worn, and the magnetic sensor 56 may be erroneously detected or may not be detected.

Therefore, it is an object of the present invention to provide a concrete pump that can be correctly detected by a sensor for a long period of time.

The present invention comprises a plurality of concrete cylinders for extruding ready-mixed concrete and a plurality of drive cylinders that reciprocate by being supplied with hydraulic oil to drive each of the plurality of concrete cylinders. A cylindrical cylinder tube, a piston that moves in the longitudinal direction with respect to the cylinder tube, a cylinder rod that is fixed to the piston and has a hollow portion that extends in the longitudinal direction inside, and the cylinder rod with respect to the cylinder tube. The stroke sensor includes a stroke sensor for detecting the amount of movement of the cylinder tube, the stroke sensor is fixed to the base end side of the cylinder tube and is located in the hollow portion, and a rod-shaped sensor rod made of a magnetic material and the piston or the said. It is a magnetic strain type sensor provided with a magnet fixed to the cylinder rod facing the outer peripheral surface of the sensor rod, and the hollow portion of the cylinder rod has an inner surface of the hollow portion and an outer surface of the sensor rod. It is a concrete pump which is separated from the above and has a cushioning layer formed which is softer than the sensor rod.

According to the above configuration, the cushioning layer can prevent the cylinder rod and the sensor rod from coming into direct contact with each other. Therefore, it is possible to prevent the sensor rod from being worn due to the movement of the piston and the cylinder rod.

Furthermore, the cushioning layer may include a tubular body inserted into the hollow portion.

According to this configuration, the buffer layer is formed by inserting the tubular body into the hollow portion, so that the buffer layer can be easily formed.

Furthermore, the cushioning layer may include a plurality of tubular bodies inserted into the hollow portion, and each of the plurality of tubular bodies may be formed to have the same length.

According to this configuration, a buffer layer having a desired length can be formed by appropriately combining a plurality of tubular bodies. Therefore, the manufacturing cost can be reduced.

Furthermore, the cushioning layer can be formed on the tip end side of the cylinder rod with respect to the magnet.

According to this configuration, even if the cushioning layer is displaced toward the base end side of the cylinder rod, the cushioning layer hits the magnet, so that further displacement of the cushioning layer is suppressed.

Further, a slip-preventing portion for preventing the shock-absorbing layer from slipping in the longitudinal direction by abutting is provided, and the slip-preventing portion may be formed at intervals in the longitudinal direction with respect to the cushioning layer. ..

According to this configuration, even when the buffer layer is thermally expanded, it is possible to prevent the buffer layer extending in the longitudinal direction from colliding with the slip prevention portion.

According to the present invention, it is possible to prevent the sensor rod from being worn due to the movement of the piston and the cylinder rod. Therefore, it is possible to provide a concrete pump that can be correctly detected by a sensor for a long period of time.

It is a schematic diagram which shows the structure of the hydraulic circuit about the concrete pump which concerns on one Embodiment of this invention. It is a radial sectional view which shows the whole of the concrete cylinder in the concrete pump. It is an enlarged view of the main part of FIG. FIG. 3 is an enlarged view of a main part of a radial cross section of a concrete cylinder (a state in which a rod is pulled out from the state of FIG. 3) in the concrete pump. It is a radial sectional view which shows the structure of the hydraulic cylinder in the conventional concrete pump.

Next, one embodiment of the present invention will be taken up and described. The concrete pump 1 of the present embodiment is mounted on, for example, a concrete pump vehicle which is a vehicle used when placing ready-mixed concrete in a building or the like. In the concrete pump vehicle, the ready-mixed concrete supplied from the concrete mixer vehicle or the like is supplied to the hopper located at the rear of the vehicle, and the ready-mixed concrete located inside the hopper is pumped by the concrete pump 1. This pumped ready-mixed concrete can be sent to the casting location via piping.

The concrete pump 1 of the present embodiment includes a concrete cylinder 11 and a drive cylinder 12.

A plurality of concrete cylinders 11 are provided for extruding ready-mixed concrete with respect to connected pipes and the like. In this embodiment, two concrete cylinders 11 and 11 are provided in parallel.

A plurality of drive cylinders 12 are provided to reciprocate due to the supply of hydraulic oil to drive each of the plurality of concrete cylinders 11 and 11. The drive cylinder 12 is provided coaxially with the concrete cylinder 11. Therefore, the cylinder rod 121 included in the drive cylinder 12 is connected to the rod 111 included in the concrete cylinder 11 at the tip end portion (see FIG. 1). In this embodiment, two drive cylinders 12 and 12 are provided in parallel, and each drive cylinder 12 is provided in each concrete cylinder 11 in a one-to-one correspondence. The hydraulic oil sent from the hydraulic pump 13 which is the supply source of the hydraulic oil is supplied to the inside of each drive cylinder 12 from the hydraulic oil inlet / outlet 124 at the end on the side of the concrete cylinder 11 (end on the side of the cylinder rod 121). Each drive cylinder 12 contracts.

When the ready-mixed concrete is pumped, each drive cylinder 12 expands and contracts alternately. Since the rods 111 and 121 are connected to each other, each concrete cylinder 11 also expands and contracts alternately. Inside the hopper included in the concrete pump truck, a switching member 2 that swings so that the rear end opening 112 of each concrete cylinder 11 can be opened or covered is provided (see FIG. 1). The switching member 2 is a curved pipe-shaped member that connects the base end portion of the concrete pumping pipe (not shown) provided in the concrete pump truck to the rear end opening 112 of each concrete cylinder 11. Each concrete cylinder 11 sucks ready-mixed concrete located inside the hopper with the rear end opening 112 not covered by the switching member 2. Then, after the switching member 2 swings to cover the rear end opening 112, ready-mixed concrete is extruded from each concrete cylinder 11 to the switching member 2. By repeating this, ready-mixed concrete is continuously pumped to the concrete pumping pipe.

2 to 4 show the drive cylinder 12. FIG. 2 shows the most contracted state. FIG. 3 shows the base end portion in the state of FIG. FIG. 4 shows a base end portion slightly extended from the states of FIGS. 2 and 3. The drive cylinder 12 is a cylinder rod provided with a cylindrical cylinder tube 122, a piston 123 that moves in the longitudinal direction with respect to the cylinder tube 122, and a hollow portion 121a that is fixed to the piston 123 and extends in the longitudinal direction inside. It includes 121 (already mentioned) and a stroke sensor 3 that detects the amount of movement of the cylinder rod 121 with respect to the cylinder tube 122.

The stroke sensor 3 is fixed to the base end side of the cylinder tube 122 and is located in the hollow portion 121a, and has a rod-shaped sensor rod 31 made of a magnetic metal and the sensor rod 31 attached to the piston 123 or the cylinder rod 121. It is a magnetostrictive type sensor including a magnet 32 fixed facing the outer peripheral surface of the cylinder tube and a detection unit 36 connected to a sensor rod 31 on the proximal end side of the cylinder tube 122. Since the principle of the magnetostrictive sensor is known, it will be briefly described. A pulse current is input to the sensor rod 31 from the proximal end side. As a result, a magnetic field is generated around the sensor rod 31. In the vicinity of the magnet 32, the sensor rod 31 is affected by the magnetic field of the magnet 32, and a minute torsional strain is locally generated. This torsional strain is transmitted to the base end side of the sensor rod 31 as vibration. By detecting this torsional strain (vibration) by the detection unit 36, the position of the magnet with respect to the sensor rod 31 can be measured.

The magnet 32 of the present embodiment has a ring shape provided so as to surround the out-of-diameter position of the sensor rod 31 on the inner surface of the cylinder rod 121. The magnet 32 is sandwiched between the magnet support rings 33 from the proximal end side and the distal end side in the axial direction (longitudinal direction of the drive cylinder 12) with respect to the sensor rod 31. Further, a spacer 34 is provided on the tip end side of the magnet support ring 33 on the tip end side. The spacer 34 abuts on a step formed on the inner circumference of the cylinder rod 121. These are fixed to the cylinder rod 121 by fitting the snap ring 35 on the inner surface of the cylinder rod 121 on the proximal end side of the magnet support ring 33 on the proximal end side. The spacer 34 has a ring shape fixed to the cylinder rod 121, and functions as a slip prevention portion for preventing the cushion layer 4 described later from slipping in the longitudinal direction by abutting.

In the hollow portion 121a of the cylinder rod 121, an inner surface of the hollow portion 121a and an outer surface of the sensor rod 31 are separated from each other, and a cushioning layer 4 which is softer than the sensor rod 31 is formed. The cushioning layer 4 of the present embodiment is arranged so as to abut on the inner surface of the hollow portion 121a in the cylinder rod 121. Further, the tip of the buffer layer 4 coincides with the tip of the hollow portion 121a, and the base end is located on the tip side of the base end of the hollow portion 121a. By forming the soft buffer layer 4 in this way, the cylinder rod 121 and the sensor rod 31 can be prevented from coming into direct contact with each other. Therefore, it is possible to prevent the sensor rod 31 from being worn as the piston 123 and the cylinder rod 121 move.

The cushioning layer 4 of the present embodiment is a tubular body 41 inserted into the hollow portion 121a of the cylinder rod 121. By using the tubular body 41 as the buffer layer 4, the buffer layer 4 is formed by inserting the tubular body 41 into the hollow portion 121a, so that there is an advantage that the buffer layer 4 can be easily formed. In this embodiment, a resin pipe is used. When a pipe is used, in addition to the resin, a pipe made of a metal softer than the metal (magnetic material) constituting the sensor rod 31, such as an alumnium alloy or brass, can also be used. When a resin is used, it may be a soft resin or a hard resin.

The tubular body 41 may be a single real body continuous in the longitudinal direction. Alternatively, a plurality of tubular bodies 41 ... 41 can be used by connecting them in the longitudinal direction. In FIGS. 3 and 4, the boundary lines of the adjacent cylindrical bodies 41 and 41 appear. Thereby, the buffer layer 4 having a desired length can be formed by appropriately combining a plurality of tubular bodies 41 ... 41. Therefore, the manufacturing cost can be reduced. In particular, it is advantageous to form each of the plurality of tubular bodies 41 ... 41 to have the same length because it is possible to suppress management costs and mistakes in selecting the length of the tubular bodies 41 during manufacturing.

The cushioning layer 4 is formed on the tip end side of the cylinder rod 121 with respect to the magnet 32 constituting the stroke sensor 3. With such a positional relationship, even if the cushioning layer 4 (cylindrical body in the present embodiment) is displaced toward the base end side of the cylinder rod 121, the cushioning layer 4 hits the magnet 32, so that the cushioning layer 4 has a positional relationship. Further deviation is suppressed.

Further, the cushioning layer 4 is formed at intervals in the longitudinal direction with respect to the portion of the stroke sensor 3 provided on the side of the cylinder rod 121 including the magnet 32. In the present embodiment, as shown in FIG. 3, the buffer layer 4 is formed with an interval D with respect to the spacer 34 provided when the magnet 32 is fixed to the cylinder rod 121. Here, as an example, the distance associated with the expansion and contraction of the drive cylinder 12 is about 2 m, and the time required for one-way stroke is 2 to 3 seconds. Then, in connection with the switching of the two concrete cylinders 11 and 11 to which the two drive cylinders 12 and 12 are connected, the switching of the switching member 2 is performed in about 0.3 seconds. Since the drive speed of the concrete pump 1 is high as described above, the drive cylinder 12 during operation is heated to a high temperature. Along with this, thermal expansion occurs in the buffer layer 4 (cylindrical body in this embodiment). On the other hand, by setting the spacer 34 and the buffer layer 4 in the positional relationship of the present embodiment, when the buffer layer 4 thermally expands, it abuts on the spacer 34 and cannot expand in the longitudinal direction but expands in the radial direction. Therefore, it is possible to prevent the hollow portion 121a from becoming narrow and obstructing the flow of hydraulic oil (which may cause abnormal vibration in the sensor rod 31). Further, even when the buffer layer 4 is thermally expanded in the longitudinal direction, it is possible to prevent the buffer layer 4 extending in the longitudinal direction from pressing the magnet 32 and causing a problem in the detection of the stroke sensor 3.

Although the present invention has been described above by taking up embodiments, the present invention is not limited to these embodiments.

For example, the concrete pump 1 of the above embodiment was mounted on a concrete pump truck. However, the concrete pump 1 of the present invention is not limited to the vehicle-mounted vehicle, and may be a stationary type. Since the concrete pump 1 receives the vibration of the vehicle in the vehicle-mounted vehicle as in the above embodiment, the concrete pump 1 is in a more disadvantageous condition, so that the effect of the present invention can be further obtained.

Further, in the above embodiment, the cushioning layer 4 is arranged so as to abut on the inner surface of the hollow portion 121a in the cylinder rod 121. However, it may be arranged so as to abut on the outer surface of the sensor rod 31.

Further, in the above embodiment, the cushioning layer 4 is a tubular body inserted into the hollow portion 121a of the cylinder rod 121. However, the cushioning layer 4 is not limited to this, and can be implemented by protrusions formed of a soft material such as a resin coating, a coating film, and a brush-like body protruding in the radial direction. In the case of carrying out with protrusions, a plurality of protrusions can be provided at predetermined intervals, and the intervals may be set so as not to allow the sensor rod 31 to enter. That is, the distance may be such that the sensor rod 31 can hold the cylinder rod 121 (float with respect to the inner surface) so that the sensor rod 31 does not abut on the inner surface of the hollow portion 121a of the cylinder rod 121. If the cross section of the rod-shaped sensor rod 31 is circular as in the above embodiment, the distance between the protrusions in the circumferential direction may be smaller than the diameter of the cross section of the sensor rod 31. Further, in the case of a cushioning layer that does not need to be in close contact with a surface such as a cylindrical body, the cushioning layer may be fixed to the inner surface of the hollow portion 121a or the like, or may simply abut.

Further, in the above embodiment, the spacer 34 in the stroke sensor 3 functions as a slip prevention portion for preventing the shock absorber 4 from slipping in the longitudinal direction by abutting. However, it is also possible to provide a dedicated slip prevention portion separately from the spacer 34. In this case, as in the above embodiment, the cushioning layer 4 is formed with a distance D in the longitudinal direction with respect to the dedicated slip-preventing portion.

1 Concrete pump 11 Concrete cylinder 12 Drive cylinder 121 Cylinder rod 121a Hollow part 122 Cylinder tube 123 Piston 3 Stroke sensor 31 Sensor rod 32 Magnet 34 Anti-slip part, spacer 4 Buffer layer 41 Cylindrical body D Interval

Claims (4)

With multiple concrete cylinders that extrude ready-mixed concrete,
It is provided with a plurality of drive cylinders that reciprocate by being supplied with hydraulic oil to drive each of the plurality of concrete cylinders.
The drive cylinder includes a cylindrical cylinder tube, a piston that moves in the longitudinal direction with respect to the cylinder tube, a cylinder rod that is fixed to the piston and has a hollow portion that extends in the longitudinal direction inside, and the cylinder. A stroke sensor that detects the amount of movement of the cylinder rod with respect to the tube is provided.
The stroke sensor is fixed to the base end side of the cylinder tube and is located in the hollow portion, and has a rod-shaped sensor rod made of a magnetic material and the piston or the cylinder rod facing the outer peripheral surface of the sensor rod. It is a magnetostrictive sensor with a fixed magnet and
In the hollow portion of the cylinder rod, an inner surface of the hollow portion and an outer surface of the sensor rod are separated from each other, and a cushioning layer that is softer than the sensor rod is formed .
The cushioning layer is provided with a slip-preventing portion that prevents the shock-absorbing layer from slipping in the longitudinal direction by abutting.
The slip stopper is a concrete pump formed at intervals in the longitudinal direction with respect to the cushioning layer . The concrete pump according to claim 1, wherein the cushioning layer includes a tubular body inserted into the hollow portion. The cushioning layer comprises a plurality of tubular bodies inserted into the hollow portion.
The concrete pump according to claim 2, wherein each of the plurality of tubular bodies is formed to have the same length. The concrete pump according to any one of claims 1 to 3, wherein the cushioning layer is formed on the tip end side of the cylinder rod with respect to the magnet.

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