Water supply device for blade

Abstract

Provided is a water supply device for a blade capable of continuously supplying a sufficient amount of cooling water from a water supply tank to a blade, and reliably and smoothly executing water supply work in cutting work.　The present invention is characterized in that: the water supply device has a pressurizing case 4 surrounding an outer side of an outer peripheral surface of a blade shaft 2 and forming a pressure chamber 45; an impeller 8 is fixed, in the pressure chamber 45, to the outer peripheral surface of the blade shaft 2; a region on the inner side in the radial direction in the pressure chamber 45 is configured to communicate with supply passages (an introduction chamber 44, the water supply tank and the like) on the upstream side for supplying cooling water to the pressure chamber 45; and a region on the outer side in the radial direction in the pressure chamber 45 is configured to communicate with supply passages (a water supply chamber 46, a central water passage 21 and the like) on the downstream side for supplying cooling water to a blade 6.

Description

Blade water supply device

[0001] The present invention relates to a device for supplying cooling water to blades used for cutting or milling asphalt pavement, concrete, stone, metal materials, etc., and in particular to a water supply device for blades that can be applied to work machines that use blades that rotate at high speeds, such as concrete cutters (devices that cut or mill the asphalt pavement surface or concrete surface of a road) used in road repair work, removal work, etc.

[0002] Some concrete cutters used in road repair and removal work are equipped with a blade water supply system that supplies cooling water to both the left and right sides of the blade (known as wet concrete cutters). Wet concrete cutters can cool the blade disk and tip during cutting work and prevent dust from flying.

[0003] Conventional wet concrete cutters employ a water supply system in which multiple nozzles are located near the blade (e.g., inside the blade cover), and these nozzles are connected to a water tank with hoses to spray cooling water onto both the left and right sides of the blade. Also employed is a system in which a water channel is provided inside the blade shaft, one end of the blade shaft is connected to a water tank, and cooling water is sent from that end through the water channel inside the blade shaft to the opposite end, and is supplied to both sides of the blade from a position radially inward of the blade and blade fixing means (see, for example, Patent Document 1).

[0004] Conventional wet concrete cutters often use a gravity-fed water supply system, where cooling water is delivered from a water tank to a location near the blade. In this case, the water tank must be installed higher than the nozzle and the water channels inside the blade shaft. However, when using a concrete cutter that does not use a gravity-fed water supply system, or when circumstances make it impossible to supply water by gravity, a water pump is used to simultaneously supply water and cut the concrete.

[0005] Japanese Patent No. 6120197 Japanese Patent Laid-Open No. 2022-062420 Japanese Utility Model Laid-Open No. 55-004114 Japanese Utility Model Laid-Open No. 55-004113

[0006] When using a gravity-fed wet concrete cutter for cutting work, a problem occurs: the supply pressure and flow rate decrease as the water level in the water tank drops. For example, when the amount of cooling water remaining in the water tank becomes low, the pressure and flow rate required to spray cooling water from the nozzle or the pressure and flow rate required to send cooling water through the water passage inside the blade shaft and supply it to the blade from a position radially inward of the blade and blade fixing means cannot be obtained, and the cooling water may not reach the blade. In this case, the blade cannot be properly cooled, which can cause blade deterioration and shorten its lifespan and prevent dust from flying.

[0007] Therefore, in order to maintain the pressure and flow rate necessary to properly supply cooling water, it is necessary to replenish water in the water supply tank in parallel with cutting operations or by interrupting cutting operations.

[0008] Furthermore, when using a water supply pump to perform cutting work and water supply work simultaneously, a separate power source (battery, commercial power, engine generator, etc.) must be secured to operate the water supply pump, which is extremely troublesome and incurs additional costs. Furthermore, the concrete cutter and the water supply pump must be operated simultaneously, which is difficult for a single worker to perform.

[0009] The present invention seeks to solve the problems associated with the prior art, and aims to provide a blade water supply device that can continuously supply a sufficient amount of cooling water from a water supply tank to the blade, enabling water supply operations to be carried out reliably and smoothly during cutting operations.

[0010] The blade water supply device of the present invention can be applied to a device that rotates a blade fixed to a blade shaft to cut or mill an object, and is characterized in that it has a pressurized case that surrounds the outside of the outer surface of the blade shaft and forms a circular pressure chamber between the outer surface of the blade shaft, and an impeller is fixed to the outer surface of the blade shaft within the pressure chamber or formed integrally with the blade shaft, and the radially inner region of the pressure chamber is configured to communicate with an upstream supply passage that supplies cooling water to the pressure chamber, and the radially outer region of the pressure chamber is configured to communicate with a downstream supply passage that supplies cooling water to the blade, and as the impeller rotates within the pressure chamber, the pressure in the radially inner region of the pressure chamber decreases, causing cooling water to continuously flow into the pressure chamber from the upstream supply passage, and the pressure in the radially outer region of the pressure chamber increases, causing cooling water to continuously flow out of the pressure chamber to the downstream supply passage.

[0011] Furthermore, in this blade water supply device, it is preferable that one end opens in the pressure chamber, a tangential flow path extending tangentially to the inner surface of the pressure chamber is connected to the pressure chamber, and the cooling water flows from the radially outer region of the pressure chamber through the tangential flow path to the downstream supply path.

[0012] Preferably, the impeller has a plurality of blades, each of which is formed so that its front end in the direction of rotation is located radially inward relative to its rear end in the direction of rotation, so that, during rotation, the fluid in the front of the direction of rotation is moved radially outward. Preferably, the blade shaft is rotatably supported by two bearings spaced apart in the longitudinal direction, and the pressurized case is located between the bearings.

[0013] Furthermore, it is preferable that an air vent hole for releasing air that may be present in the pressure chamber is formed at a position higher than the position where the radially inner region of the pressure chamber communicates with the upstream supply passage.

[0014] In addition, a water supply chamber through which the blade shaft passes is formed within the pressurized case, and the pressure chamber and the water supply chamber are connected via a connecting flow path including a tangential flow path; a central water passage extending along the central axis of the blade shaft, a first radial water passage having one end opening on the outer circumferential surface of the blade shaft within the water supply chamber and the other end reaching the central water passage, and a second radial water passage having one end opening on the outer circumferential surface of the blade shaft radially inside the blade fixing means and the other end reaching the central water passage are formed within the blade shaft; and flange flow paths are formed between the blade fixing means and the blades, or within the blade fixing means, that connect from the outer circumferential surface of the blade shaft to the outer circumferential surface of the blade fixing means, and it is preferable that the impeller rotates within the pressure chamber, and the cooling water flowing out of the pressure chamber passes through the connecting flow path, the water supply chamber, the first radial water passage, the central water passage, the second radial water passage, and the flange flow paths and is supplied to the blades.

[0015] Furthermore, it is preferable that an inlet chamber through which the blade shaft passes is formed within the pressurized case, the inlet chamber is connected to a water supply tank that supplies cooling water, and is configured to communicate with a radially inner region within the pressure chamber, so that the cooling water supplied from the water supply tank flows from the inlet chamber into the radially inner region within the pressure chamber.

[0016] It is also preferable that a partition having an opening through which the blade shaft is inserted is formed between the pressure chamber and the introduction chamber in the pressurized case, the inner diameter of the opening in the partition being set to a dimension larger than the outer diameter of the blade shaft, and the radially inner region of the pressure chamber being connected to the introduction chamber by a gap between the opening and the blade shaft.

[0017] Furthermore, it is preferable that the impeller has a plurality of blades, and the distance between the tip of the blade and the partition wall is set to 1.5 mm or less.

[0018] The blade water supply device of the present invention can obtain a higher supply pressure and flow rate than conventional water supply devices that deliver cooling water by gravity. Furthermore, it can continuously deliver a sufficient amount of cooling water to the blades regardless of the water level (remaining water amount) in the water supply tank. Furthermore, the water supply tank does not need to be installed at a high position; it can be installed at a position lower than the blade shaft. This is expected to provide greater design freedom in terms of the installation position of the water supply tank.

[0019] Furthermore, since the amount of cooling water supplied to the blades is proportional to the rotation speed of the impeller, if the output of the power source (engine, etc.) is increased during cutting work to rotate the blade shaft and impeller at high speed, a large amount of cooling water (enough to cool the blades and prevent dust from scattering) will be appropriately supplied. Conversely, when idling, the amount of water supplied will decrease, automatically saving water.

[0020] FIG. 1 is a horizontal cross-sectional view of a blade water supply device 1 according to the present invention. FIG. 2 is an enlarged cross-sectional view of the pressurizing case 4 shown in FIG. 1. FIG. 3 is a vertical cross-sectional view of the water supply device 1 taken along line III-III shown in FIG. 2. FIG. 4 is a cross-sectional perspective view of the pressurizing case 4 taken along line IV-IV shown in FIG. 3. FIG. 5 is a perspective view of the impeller 8 shown in FIGS. 1 to 3. FIG. 6 is an enlarged cross-sectional view of the tip of the blade shaft 2 and the blade fixing means 3 shown in FIG. 1. FIG. 7 is a perspective view of the outer flange 32 of the blade fixing means 3 shown in FIG. 6. FIG. 8 is a vertical cross-sectional view showing another example of the configuration of the pressurizing case 4 shown in FIG. 2. FIG. 9 is a cross-sectional perspective view showing another example of the configuration of the pressurizing case 4 shown in FIG. 2.

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a horizontal cross-sectional view of a blade water supply device 1 according to the present invention (as applied to a concrete cutter that cuts or grinds asphalt pavement surfaces or concrete surfaces on roads). As shown in the figure, this water supply device 1 is basically composed of a blade shaft 2, blade fixing means 3, and a pressure case 4. Note that Fig. 1 shows a horizontal cross-section of each element at the height of the central axis of the blade shaft 2.

[0022] 1, the blade shaft 2 is rotatably supported by two bearings 5 ​​spaced apart in the longitudinal direction. The blade shaft 2 is configured to rotate at high speed by receiving a driving force transmitted from a prime mover (engine, electric motor, etc.) not shown.

[0023] A central water passage 21 extending along the central axis is formed inside the blade shaft 2. Radial water passages 22 (first radial water passage 22a, second radial water passage 22b) extending radially are also formed inside the blade shaft 2. One end of the radial water passage 22 opens on the outer circumferential surface of the blade shaft 2, and the other end reaches the central water passage 21. Therefore, the central water passage 21 formed inside the blade shaft 2 communicates with the space outside the blade shaft 2 via the radial water passage 22.

[0024] A means for fixing the blade 6 (blade fixing means 3) is attached to the tip of the blade shaft 2. The blade fixing means 3 is basically composed of an inner flange 31 and an outer flange 32. The inner flange 31 is fixed to the blade shaft 2. On the other hand, the outer flange 32 is structured to be sandwiched between the inner flange 31 and a nut 7. Then, as shown in FIG. 1 , with the blade 6 sandwiched between the inner flange 31 and the outer flange 32, the nut 7 is attached to the tip of the blade shaft 2 and tightened, thereby fixing the blade 6 to the blade shaft 2.

[0025] A pressurizing case 4 is disposed in the middle of the blade shaft 2 (at a position between the two bearings 5), surrounding the outside of the outer circumferential surface of the blade shaft 2 and forming an annular small chamber (such as a pressure chamber) between itself and the outer circumferential surface of the blade shaft 2. A hollow portion 41 having a circular cross section is formed inside the pressurizing case 4, and the blade shaft 2 is inserted coaxially into this hollow portion 41. An impeller 8 is also attached to the blade shaft 2.

[0026] 2 is an enlarged cross-sectional view of the pressurizing case 4 shown in FIG. 1. As shown in the figure, a partition wall 42 is formed inside the hollow portion 41 of the pressurizing case 4. A circular opening 42a is formed in the center of the partition wall 42. The inner diameter of the opening 42a is set to be larger than the outer diameter of the blade shaft 2 to be inserted therethrough. In this embodiment, the inner diameter of the opening 42a is set to 32 mm, and the outer diameter of the blade shaft 2 is set to 28 mm. Because the circular opening 42a is concentric with the blade shaft 2, when the blade shaft 2 is inserted into the hollow portion 41, a constant gap C (2 mm) is formed around the entire circumference between the opening 42a and the blade shaft 2.

[0027] Ring-shaped shaft seal members 43 (first shaft seal member 43a, second shaft seal member 43b, third shaft seal member 43c) are disposed in the cavity 41. These shaft seal members 43 are all contact type, and are attached such that their inner lip portions contact the blade shaft 2 and their outer portions are in close contact with the inner circumferential surface of the cavity 41.

[0028] The first shaft seal member 43a is attached to one end of the cavity 41 (the left end in FIG. 2, the end on the blade 6 side in FIG. 1). The second shaft seal member 43b is attached to the opposite end (the right end in FIG. 2). The third shaft seal member 43c is attached between the first shaft seal member 43a and the partition wall 42.

[0029] In this way, the pressurizing case 4 has openings at both ends of the cavity 41 (between the inner peripheral surface of the cavity 41 and the outer peripheral surface of the blade shaft 2) closed by the first shaft seal member 43a and the second shaft seal member 43b. The cavity 41 is divided into three small chambers by the shaft seal members 43a to 43c and the partition wall 42. More specifically, the cavity 41 is divided into an introduction chamber 44 between the second shaft seal member 43b and the partition wall 42, a pressure chamber 45 between the partition wall 42 and the third shaft seal member 43c, and a water supply chamber 46 between the third shaft seal member 43c and the first shaft seal member 43a.

[0030] Figure 3 is a vertical cross-sectional view of the water supply device 1 taken along line III-III in Figure 2. Figure 4 is a cross-sectional perspective view of the pressurizing case 4 taken along line IV-IV in Figure 3. As shown in these figures, a connecting flow path 47 is formed inside the pressurizing case 4. This connecting flow path 47 connects and communicates the pressure chamber 45 and the water supply chamber 46. In this embodiment, as shown in Figure 4, the connecting flow path 47 is composed of a main flow path 47a, a tangential flow path 47b, and a communication flow path 47c.

[0031] The main flow path 47a extends radially outside the hollow portion 41, from a position on the side of the introduction chamber 44 (in a direction perpendicular to the central axis of the blade shaft 2) to a position on the side of the water supply chamber 46, in a direction parallel to the central axis of the blade shaft 2 (see Figures 1 to 3).

[0032] As shown in Fig. 3, the tangential flow passage 47b extends in the tangential direction of the inner circumferential surface of the hollow portion 41 (pressure chamber 45), with one end opening in the pressure chamber 45 and the other end opening in the main flow passage 47a. Therefore, the pressure chamber 45 and the main flow passage 47a are communicated with each other via the tangential flow passage 47b. As shown in Fig. 4, the communication flow passage 47c has one end opening in the main flow passage 47a and the other end opening in the water supply chamber 46. Therefore, the main flow passage 47a and the water supply chamber 46 are communicated with each other via the communication flow passage 47c.

[0033] As shown in Fig. 4, a water conduit 48 is formed inside the pressurization case 4. This water conduit 48 is used to introduce cooling water into the introduction chamber 44 from outside the pressurization case 4. One end of the water conduit 48 opens on the outer surface of the pressurization case 4, and the other end opens in the introduction chamber 44. The outer opening of the water conduit 48 is connected to a water supply tank (not shown) by a hose, a pipe, or the like.

[0034] 4, an air vent hole 49 is formed between the main flow path 47a and the introduction chamber 44. This air vent hole 49 is for allowing air that may be present in the pressure chamber 45 and the connecting flow path 47 to escape to the introduction chamber 44 side, thereby allowing a sufficient amount of cooling water to flow into the pressure chamber 45 and the connecting flow path 47 when the water supply device 1 is started, etc.

[0035] The cross-sectional area of ​​the air vent hole 49 is set to be much smaller than the gap C shown in Figure 2 (the gap between the opening 42a of the partition wall 42 and the blade shaft 2) and the cross-sectional area of ​​the connecting flow path 47.

[0036] 1 to 3. The impeller 8 is basically composed of a cylindrical (or ring-shaped) base 81 and a plurality of (four in this example) blades 82 protruding in a direction parallel to the central axis from one side surface (a surface perpendicular to the central axis) of the base 81. As shown in FIG. 3, the impeller 8 is configured such that the base 81 is fixed to the outer circumferential surface of the blade shaft 2 within the pressure chamber 45 and rotates together with the blade shaft 2 in a predetermined direction (counterclockwise in FIGS. 3 and 5).

[0037] The blades 82 of the impeller 8 are configured so that, during rotation, they can move (push out) radially outward the fluid in front of the blade 82 in the direction of rotation. More specifically, as shown in Fig. 5, each blade 82 is formed so that its front end 82a (the end on the front side in the direction of rotation) is located radially inward relative to its rear end 82b (the end on the rear side in the direction of rotation).

[0038] 2, the impeller 8 is disposed so that the axial tip of the blade 82 (the right end in FIG. 2) is located as close as possible to the partition wall 42. In this embodiment, the distance between the blade 82 and the partition wall 42 is set to 0.8 mm (preferably 1.5 mm or less).

[0039] Here, we will explain the operation of the blade water supply device 1 according to this embodiment. This water supply device 1 supplies rotational driving force from a prime mover (not shown) to the blade shaft 2 (see FIGS. 1 to 3), causing the blade shaft 2 and impeller 8 to rotate in a predetermined direction (counterclockwise in FIG. 3), thereby generating the pressure necessary to supply cooling water from a water tank (not shown) to both sides of the blades 6.

[0040] This supply pressure is generated within the pressurized case 4. However, it is necessary that a sufficient amount of water is present within the pressurized case 4. Therefore, if there is no water present within the pressurized case 4 or if the amount of water is insufficient, first, a sufficient amount of water is introduced into the pressurized case 4. Specifically, water is supplied from a water supply tank (not shown) to the introduction chamber 44 via the water conduit 48 (see FIG. 4).

[0041] The introduction chamber 44 and the adjacent pressure chamber 45 are separated by a partition wall 42, with a gap C (see FIG. 2) formed between the opening 42a of the partition wall 42 and the blade shaft 2. As shown in FIG. 4, the pressure chamber 45 is connected to the adjacent water supply chamber 46 by connecting passages 47 (main passage 47a, tangential passage 47b, and communication passage 47c). Therefore, when a sufficient amount of water is supplied to the introduction chamber 44, the water flows into the pressure chamber 45 through the gap C and further flows into the water supply chamber 46 through the connecting passage 47.

[0042] When the water level in the introduction chamber 44 becomes higher than the top 42b of the opening 42a of the partition wall 42 (see FIG. 4), if there is no escape route for the air present in the space above the top 42b of the opening 42a of the partition wall 42 among the spaces in the pressure chamber 45, the connecting flow path 47, and the water supply chamber 46 (hereinafter simply referred to as the "space above the pressure chamber 45, etc."), it becomes difficult to allow a sufficient amount of water to flow into the pressure chamber 45 and the connecting flow path 47. In this case, air entrainment occurs when the impeller 8 is rotated, and it may not be possible to obtain a sufficient supply pressure and flow rate.

[0043] In this embodiment, as described above, an air vent hole 49 (see FIG. 4) is formed between the main flow path 47a of the connecting flow path 47 and the introduction chamber 44, and this air vent hole 49 is formed at a position sufficiently higher than the top 42b of the opening 42a of the partition wall 42, so that air in the space above the pressure chamber 45, etc., can escape to the introduction chamber 44 side, allowing a sufficient amount of water to flow into the pressure chamber 45, the connecting flow path 47, and the water supply chamber 46. As a result, the problem of air entrainment can be suitably avoided when the water supply device 1 is in operation.

[0044] When a sufficient amount of water is present in the pressurizing case 4 and water can be continuously supplied from a water supply tank (not shown) to the introduction chamber 44, and the impeller 8 is continuously rotated, the pressure on the upstream side of the impeller 8 decreases and the pressure on the downstream side increases. As a result, water can be continuously flowed from the upstream water supply tank into the pressurizing case 4, and water can be continuously pressure-fed from the pressurizing case 4 toward the blades 6 on the downstream side.

[0045] More specifically, when the impeller 8 is rotated, the water in the pressure chamber 45 is stirred by the blades 82 (see FIGS. 3 and 5 ), generating a swirling water current in the same direction. In addition to centrifugal force acting on the swirling water current, the shape of the blades 82 (which is capable of moving fluid ahead in the direction of rotation radially outward) causes pressure to increase in the radially outer region of the pressure chamber 45 (the region along the inner circumferential surface of the pressure chamber 45). Conversely, pressure decreases in the radially inner region of the pressure chamber 45 (the region along the outer circumferential surface of the blade shaft 2).

[0046] 3, a tangential flow passage 47b opens into the inner peripheral surface of the pressure chamber 45. Because this tangential flow passage 47b extends in the tangential direction of the inner peripheral surface of the pressure chamber 45, water swirling in the radially outer region of the pressure chamber 45 continuously flows into the tangential flow passage 47b due to inertial force, and is further pushed out of the tangential flow passage 47b toward the downstream side (the main flow passage 47a, the communication flow passage 47c, the water supply chamber 46, etc.) by the pressure generated by the rotation of the impeller 8.

[0047] On the other hand, the radially inner region within the pressure chamber 45 is connected to the introduction chamber 44 (through which the blade shaft 2 passes) via the gap C (see Figure 2) between the opening 42a of the partition 42 and the blade shaft 2, so when the pressure in the radially inner region within the pressure chamber 45 decreases, the pressure difference between the introduction chamber 44 causes a water flow from the introduction chamber 44 through the gap C into the pressure chamber 45.

[0048] Furthermore, if the spacing between the blades 82 of the impeller 8 and the partition wall 42 is set large, some of the water swirling in the radially outer region of the pressure chamber 45 may pass through the gap between the blades 82 and the partition wall 42 and move to the radially inner region, which may reduce the pressure difference caused by the rotation of the impeller 8 (the pressure difference between the radially outer region and the radially inner region of the pressure chamber 45, and the pressure difference between the radially inner region of the pressure chamber 45 and the introduction chamber 44).

[0049] In this embodiment, as described above, the spacing dimension between the blades 82 of the impeller 8 and the partition wall 42 is set to an extremely small value, so that the movement of water from the radially outer region to the radially inner region within the pressure chamber 45 can be minimized, and the pressure difference generated by the rotation of the impeller 8 can be maintained appropriately.

[0050] In this way, the water supply device 1 of this embodiment can continuously rotate the impeller 8 within the pressure chamber 45, thereby continuously flowing water into the pressure chamber 45 from the upstream side (inlet chamber 44, etc.), and can pressurize water from the pressure chamber 45 toward the downstream side (water supply chamber 46, etc.).

[0051] The water forced out from the pressure chamber 45 flows into the water feed chamber 46 and is supplied to the blades 6 through water passages formed inside the blade shaft 2. Specifically, as shown in FIG. 2 , the blade shaft 2 is disposed so as to pass through the water feed chamber 46, and the central water passage 21, the first radial water passage 22a, and the second radial water passage 22b (see FIG. 1) are formed inside the blade shaft 2. Of these, as shown in FIG. 2 , the first radial water passage 22a has one end opening in the water feed chamber 46 and the other end reaching the central water passage 21. Therefore, the water that has flowed into the water feed chamber 46 flows from the water feed chamber 46 into the first radial water passage 22a due to the pressure generated by the rotation of the impeller 8.

[0052] Since the first radial water passage 22a extends radially inside the blade shaft 2, centrifugal force acts on the water in the first radial water passage 22a when the blade shaft 2 rotates. This centrifugal force acts as resistance when water is attempted to flow from the water supply chamber 46 into the first radial water passage 22a (i.e., when water is attempted to move from the radial outside to the radial inside). However, the water supply device 1 of this embodiment can generate a sufficiently large supply pressure during normal operation of the concrete cutter to which it is applied, allowing water to flow from the water supply chamber 46 into the first radial water passage 22a without any problems.

[0053] For example, when the blade shaft 2 and the impeller 8 are rotated at a speed (3200 to 3600 rpm) that is normally used for a concrete cutter, a large supply pressure of 24 to 28 kPa can be generated, which allows water to flow from the water supply chamber 46 into the first radial water passage 22 a without any problems, despite the centrifugal force acting in the first radial water passage 22 a.

[0054] The water that has flowed into the first radial water passage 22a passes through the central water passage 21 and is sent to the second radial water passage 22b, from which it flows out to the outside of the blade shaft 2. As shown in Figure 6 (an enlarged cross-sectional view of the tip of the blade shaft 2 and the blade fixing means 3 shown in Figure 1), the second radial water passage 22b is formed at a position radially inward of the blade fixing means 3 (inner flange 31, outer flange 32) and the blades 6 fixed thereto.

[0055] As shown in Fig. 7 (a perspective view of the outer flange 32 of the blade fixing means 3 shown in Fig. 6), a pressing portion 32a, a recessed portion 32b, and a groove portion 32c are formed on the inner surface (the surface that comes into contact with the blade 6) of the outer flange 32 of the blade fixing means 3. Of these, the pressing portion 32a and the grooved portion 32c are formed in a radially outer region of the inner surface of the outer flange 32, and the recessed portion 32b is formed in a radially inner region (the region between the pressing portion 32a and a through hole 32d through which the blade shaft 2 is inserted).

[0056] The pressing portion 32a is a portion that contacts and presses against the side surface of the blade 6 to fix the blade 6, and is formed to be located on the same plane perpendicular to the central axis. On the other hand, the recessed portion 32b and the groove portion 32c are shaped to be recessed from the plane of the pressing portion 32a in the thickness direction of the outer flange 32. Therefore, when the outer flange 32 is pressed against the side surface of the blade 6, only the pressing portion 32a comes into contact with the side surface of the blade 6, and a space (gap) is formed between the outer flange 32 and the blade 6 in the portion where the recessed portion 32b and the groove portion 32c are formed.

[0057] The grooves 32c are formed to extend radially from the recesses 32b to the outer peripheral surface 32e of the outer flange 32. Therefore, as shown in Fig. 6, when the blade 6 is attached to the blade shaft 2 and clamped and fixed between the inner flange 31 and the outer flange 32, a flow path (flange flow path) is formed between the outer flange 32 and the blade 6, which runs from the outer peripheral surface of the blade shaft 2 through the recesses 32b and the grooves 32c to the outer peripheral surface 32e of the outer flange 32.

[0058] 7. The inner surface of the inner flange 31 also has formed thereon pressing portions 31a, recesses 31b, and grooves 31c (see FIG. 6) similar to the pressing portions 32a, recesses 32b, and grooves 32c shown in FIG. 7. In other words, between the inner flange 31 and the blade 6, a flow path (flange flow path) is formed that communicates from the outer circumferential surface of the blade shaft 2 through the recesses 31b and grooves 31c to the outer circumferential surface 31e of the inner flange 31.

[0059] Therefore, the cooling water flowing out from the blade shaft 2 at a position radially inward of the blade fixing means 3 and the blade 6 is moved radially outward by centrifugal force through the recesses 31b, 32b and grooves 31c, 32c of the inner flange 31 and the outer flange 32, and ultimately the cooling water is supplied to both sides of the blade 6.

[0060] In this way, the water supply device 1 of this embodiment is configured so that the radially inner region within the pressure chamber 45 is connected to an upstream supply passage (inlet chamber 44, water supply tank, etc.) that supplies cooling water to the pressure chamber 45, and the radially outer region within the pressure chamber 45 is connected to a downstream supply passage (water feed chamber 46, central water passage 21, etc.) that supplies cooling water to the blades 6. By rotating the impeller 8 within the pressure chamber 45, the pressure in the radially inner region within the pressure chamber 45 can be reduced, allowing cooling water to continuously flow into the pressure chamber 45 from the upstream supply passage, and the pressure in the radially outer region within the pressure chamber 45 can be increased, allowing cooling water to continuously flow out from the pressure chamber 45 to the downstream supply passage, resulting in appropriate supply of cooling water to both sides of the blades 6.

[0061] The water supply device 1 according to this embodiment can obtain a higher supply pressure and flow rate than conventional water supply devices that deliver cooling water by gravity. Furthermore, it can continuously deliver a sufficient amount of cooling water to the blades 6 regardless of the water level (remaining amount of water) in the water supply tank. Furthermore, the water supply tank does not need to be installed at a high position, and can be placed at a position lower than the blade shaft 2. Therefore, it is expected that there will be an advantage of greater design freedom in terms of the installation position of the water supply tank.

[0062] The amount of cooling water supplied to the blades 6 is proportional to the rotation speed of the impeller 8. Therefore, when the power source (engine, etc.) is increased during cutting work to rotate the blade shaft 2 and impeller 8 at high speed, a large amount of cooling water (enough to cool the blades 6 and prevent dust from scattering) is appropriately supplied, and conversely, when idling, the amount of water supplied is reduced, automatically saving water.

[0063] The water supply device 1 of this embodiment operates by driving the blade shaft 2, so there is no need to prepare a dedicated power source, and when the water supply device 1 is operated, the increased load on the power source of the blade shaft 2 (engine, electric motor, etc.) is extremely small and is barely noticeable.

[0064] In the above embodiment, the impeller 8 is manufactured separately from the blade shaft 2 and attached to the outer circumferential surface of the blade shaft 2, but an element corresponding to the blades 82 of the impeller 8 shown in Figure 5 that is integrally formed on the outside of the outer circumferential surface of the shaft can also be used as the blade shaft 2.

[0065] Furthermore, in the above embodiment, the air vent hole 49 for releasing air that may be present in the space above the pressure chamber 45 or the like is formed at a position between the connecting flow path 47 and the introduction chamber 44 inside the pressurization case 4, but as shown in Figure 8 (an enlarged vertical cross-sectional view showing another example of the configuration of the pressurization case 4), the air vent hole 49 that connects the pressure chamber 45 and the introduction chamber 44 may be formed at a position above the partition wall 42 (a position higher than the topmost part 42b of the opening 42a). In this case as well, air that may be present in the space above the pressure chamber 45 or the like can be released toward the introduction chamber 44.

[0066] 8, a vertical hole 92 may be formed that penetrates from the outer upper surface 91 of the pressurizing case 4 to the pressure chamber 45 (or the connecting flow path 47 or the water supply chamber 46), and one end of a hose 93 (or a pipe, etc.) may be connected to the upper opening of the vertical hole 92, and the other end may be connected to the introduction chamber 44 (or an element on the upstream side thereof, for example, the water conduit 48, or a hose connecting the water supply tank and the water conduit 48, etc.). In either case, by forming or arranging an air vent hole 49 or an element equivalent thereto at a position higher than the position where the radially inner region of the pressure chamber 45 communicates with the upstream supply path (the uppermost part 42b of the opening 42a), it is possible to release air that may be present in the space above the pressure chamber 45, etc.

[0067] 9, the communication flow path 47c of the connecting flow path 47 connecting the pressure chamber 45 and the water supply chamber 46 can be configured to extend downward from the terminal end of the main flow path 47a and to communicate with the water supply chamber 46 at a lower part of the water supply chamber 46 (a position lower than the central axis of the blade shaft 2). In this case, when the power source (engine, etc.) is temporarily stopped during cutting work, the phenomenon of air flowing back from the water supply chamber 46 to the pressure chamber 45 and the occurrence of air entrapment can be preferably avoided.

[0068] Furthermore, in the water supply device 1 of the above embodiment, cooling water is supplied to the blades 6 from the water supply chamber 46 through water passages (central water passage 21 and radial water passages 22) formed inside the blade shaft 2, but it is also possible to arrange nozzles at positions inside the blade cover (not shown) that is arranged to cover the outside of the blade 6 (preferably at positions where cooling water can be sprayed onto one side of the blade and onto the opposite side of the blade), and connect these nozzles to the tangential flow paths 47b (see Figure 3) with hoses or pipes, that is, to supply cooling water to the blades 6 through a path formed outside rather than inside the blade shaft 2.

[0069] In addition, in the above embodiment, flange flow paths (recesses 31b, 32b, grooves 31c, 32c) that connect from the outer peripheral surface of the blade shaft 2 to the outer peripheral surfaces 31e, 32e of the blade fixing means 3 are formed between the inner flange 31 and the outer flange 32 and the blade 6, respectively, but flange flow paths may also be formed inside the inner flange 31 and the outer flange 32.

[0070] Although the water supply device 1 of the above embodiment is applied to a concrete cutter that cuts or mills asphalt pavement or concrete surfaces on roads, the application of the present invention is not limited to concrete cutters. In other words, the present invention can be widely applied to devices that cut or mill objects by rotating a blade fixed to a blade shaft, and in which supplying cooling water to the blade or preventing dust from scattering is necessary or effective (e.g., metalworking machines, etc.).

[0071] 1: Water supply device, 2: Blade shaft, 3: Blade fixing means, 4: Pressurizing case, 5: Bearing, 6: Blade, 7: Nut, 8: Impeller, 21: Central water channel, 22: Radial water channel, 22a: First radial water channel, 22b: Second radial water channel, 31: Inner flange, 31a: Pressing portion, 31b: Recessed portion, 31c: Groove portion, 31e: Outer peripheral surface, 32: Outer flange, 32a: Pressing portion, 32b: Recessed portion, 32c: Groove portion, 32d: Through hole, 32e: Outer peripheral surface, 41: Cavity portion, 42: Partition wall, 42a: Opening portion, 42b: Uppermost portion, 43: Shaft seal member, 43a: First shaft seal member, 43b: Second shaft seal member, 43c: Third shaft seal member 44: Inlet chamber, 45: Pressure chamber, 46: Water supply chamber, 47: Connection flow path, 47a: Main flow path, 47b: Tangential flow path, 47c: Communication flow path, 48: Water conduit, 49: Air vent hole, 81: Base, 82: Blade, 82a: Front end, 82b: Rear end, 91: Outer upper surface, 92: Vertical hole, 93: Hose, C: Gap

Claims

1. A water supply device for a blade that is applied to an apparatus that rotates a blade fixed to a blade shaft to cut or mill an object, and supplies cooling water to the blade, comprising: a pressurized case that surrounds the outside of the outer circumferential surface of the blade shaft and forms an annular pressure chamber between the outer circumferential surface of the blade shaft; an impeller is fixed to the outer circumferential surface of the blade shaft within the pressure chamber or is formed integrally with the blade shaft; a radially inner region of the pressure chamber is configured to communicate with an upstream supply passage that supplies cooling water to the pressure chamber; and a radially outer region of the pressure chamber is configured to communicate with a downstream supply passage that supplies cooling water to the blade; and as the impeller rotates within the pressure chamber, the pressure in the radially inner region of the pressure chamber decreases, causing cooling water to continuously flow into the pressure chamber from the upstream supply passage, and the pressure in the radially outer region of the pressure chamber increases, causing cooling water to continuously flow out of the pressure chamber to the downstream supply passage.

2. A water supply device for blades as described in claim 1, characterized in that one end of the water supply device is opened in the pressure chamber, a tangential flow passage extending in the tangential direction of the inner peripheral surface of the pressure chamber is connected to the pressure chamber, and cooling water flows from the radially outer region of the pressure chamber through the tangential flow passage to a supply passage on the downstream side.

3. A water supply device for blades as described in claim 1, characterized in that the impeller has a plurality of blades, each of which is formed so that its front end portion on the forward side in the direction of rotation is positioned radially inward relative to its rear end portion on the rear side in the direction of rotation, and which is configured to move fluid in front of the direction of rotation radially outward during rotation.

4. A water supply device for blades as claimed in claim 1, characterized in that the blade shaft is rotatably supported by two bearings spaced apart in the longitudinal direction, and the pressurized case is disposed at a position between the bearings.

5. A water supply device for a blade as described in claim 1, characterized in that an air vent hole for releasing air that may be present in the pressure chamber is formed at a position higher than the position where the radially inner region of the pressure chamber communicates with the upstream supply passage.

6. A water supply device for blades as claimed in any one of claims 1 to 5, characterized in that a water supply chamber through which the blade shaft passes is formed within the pressurized case, the pressure chamber and the water supply chamber are connected via a connecting flow passage including a tangential flow passage, a central water passage extending along the central axis of the blade shaft, a first radial water passage having one end opening on the outer circumferential surface of the blade shaft within the water supply chamber and the other end reaching the central water passage, and a second radial water passage having one end opening on the outer circumferential surface of the blade shaft radially inward of the blade fixing means and the other end reaching the central water passage are formed within the blade shaft, a flange flow passage is formed between the blade fixing means and the blade, or within the blade fixing means, which connects from the outer circumferential surface of the blade shaft to the outer circumferential surface of the blade fixing means, and cooling water flowing out of the pressure chamber is supplied to the blades through the connecting flow passage, the water supply chamber, the first radial water passage, the central water passage, the second radial water passage and the flange flow passage when the impeller rotates within the pressure chamber.

7. A water supply device for blades as described in claim 1, characterized in that an introduction chamber through which the blade shaft passes is formed in the pressurized case, the introduction chamber is connected to a water supply tank which supplies cooling water, and is configured to communicate with the radially inner region of the pressure chamber, and the cooling water supplied from the water supply tank is configured to flow from the introduction chamber into the radially inner region of the pressure chamber.

8. A water supply device for blades as described in claim 7, characterized in that a partition having an opening through which the blade shaft passes is formed between the pressure chamber and the introduction chamber in the pressurizing case, the inner diameter of the opening of the partition is set to a dimension larger than the outer diameter of the blade shaft, and a gap between the opening and the blade shaft is provided to communicate the radially inner area of ​​the pressure chamber with the introduction chamber.

9. A water supply device for blades as described in claim 7, characterized in that the impeller has a plurality of blades, and the distance between the tip of the blade and the partition wall is set to 1.5 mm or less.

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