Nozzle head

Abstract

To provide a nozzle head capable of controlling with high precision the shape of a portion to be cut from an object. [Solution] The nozzle head 30 includes nozzles 331-334 that form water jets that collide with an object to scrape off a portion of the object, and is driven to rotate around a first central axis. A first intersection position X1, where a line D1 along the first jetting direction of the first nozzle 331 intersects with a line D2 along the second jetting direction of the second nozzle 332, and a second intersection position X2, where a line D3 along the third jetting direction of the third nozzle 333 intersects with a line D4 along the fourth jetting direction of the fourth nozzle 334, are located on a first reference plane RP1 that includes the first central axis. The lines D1 and D2 extend along the first reference plane RP1 or are plane-symmetrical to each other with respect to the first reference plane RP1. The lines D3 and D4 extend along the first reference plane RP1 or are plane-symmetrical to each other with respect to the first reference plane RP1.

Description

[Technical Field]

[0001] The present invention relates to a nozzle head. [Background technology]

[0002] A nozzle head is known that includes a nozzle for ejecting pressurized water in a direction to form a water jet that impacts an object and removes a portion of the object. The object may be, for example, bedrock or concrete. For example, the nozzle head can be used to form a hole in the object or chip concrete.

[0003] One such nozzle head is described in Patent Document 1, which has four nozzles: a first nozzle, a second nozzle, a third nozzle, and a fourth nozzle. A straight line extending along the first ejection direction, which is the ejection direction of the first nozzle, intersects with a straight line extending along the second ejection direction, which is the ejection direction of the second nozzle, at a first intersection position. A straight line extending along the third ejection direction, which is the ejection direction of the third nozzle, intersects with a straight line extending along the fourth ejection direction, which is the ejection direction of the fourth nozzle, at a second intersection position.

[0004] The first intersection position and the second intersection position are located on first offset planes and second offset planes, respectively, which are separated from the central axial plane in opposite directions, with the central axial plane including the central axis of rotation of the nozzle head sandwiched between them. A straight line along the first ejection direction and a straight line along the second ejection direction extend along the first offset plane. A straight line along the third ejection direction and a straight line along the fourth ejection direction extend along the second offset plane. Furthermore, the first intersection position and the second intersection position are separated from the orthogonal plane in opposite directions, with the orthogonal plane including the central axis of rotation of the nozzle head and orthogonal to the central axial plane sandwiched between them. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-239668 Summary of the Invention [Problem to be solved by the invention]

[0006] In the nozzle head described above, the reaction forces generated by spraying water from the first and second nozzles and the reaction forces generated by spraying water from the third and fourth nozzles generate a rotational moment that tends to rotate the nozzle head around the central axis of rotation in the same direction. This rotational moment varies relatively greatly depending on the pressure of the water sprayed from the nozzles. Therefore, it is difficult to control the rotational speed of the nozzle head with high precision. As a result, there is a problem in that it is difficult to control the shape of the portion to be scraped off from the target object with high precision.

[0007] One of the objects of the present invention is to control with high precision the shape of the portion to be cut out from the object. [Means for solving the problem]

[0008] In one aspect of the present invention, the nozzle head is a nozzle head that has a nozzle that sprays pressurized water in a spray direction so as to form a water jet that collides with an object and scrapes off a part of the object, and is driven to rotate around a first central axis.

[0009] The nozzle head has four nozzles: a first nozzle, a second nozzle, a third nozzle, and a fourth nozzle. A straight line extending along the first ejection direction, which is the ejection direction of the first nozzle, and a straight line extending along the second ejection direction, which is the ejection direction of the second nozzle, intersect at a first intersection position. A straight line extending along the third ejection direction, which is the ejection direction of the third nozzle, and a straight line extending along the fourth ejection direction, which is the ejection direction of the fourth nozzle, intersect at a second intersection position. The first intersection position and the second intersection position are located on a first reference plane, which is a plane including the first central axis. The straight line along the first ejection direction and the straight line along the second ejection direction extend along the first reference plane or are plane-symmetrical to each other with respect to the first reference plane. The straight line along the third ejection direction and the straight line along the fourth ejection direction extend along the first reference plane or are plane-symmetrical to each other with respect to the first reference plane. [Effects of the Invention]

[0010] The shape of the part to be cut out from the object can be controlled with high precision. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a rear view of the water jet apparatus of the first embodiment. [Figure 2] FIG. 2 is a perspective view of a nozzle head according to the first embodiment. [Figure 3] FIG. 2 is a perspective view of a nozzle head according to the first embodiment. [Figure 4] FIG. 2 is a rear view of the nozzle head of the first embodiment. [Figure 5] FIG. 2 is a plan view of the nozzle head of the first embodiment. [Figure 6] FIG. 2 is a cross-sectional view of the nozzle head of the first embodiment. [Figure 7] FIG. 2 is an exploded perspective view of the nozzle head of the first embodiment. [Figure 8] FIG. 2 is an exploded perspective view of the nozzle head of the first embodiment. [Figure 9] FIG. 2 is a plan view showing the jetting direction of each nozzle in the first embodiment. [Figure 10] FIG. 2 is a side view showing the jetting direction of each nozzle in the first embodiment. [Figure 11] FIG. 2 is a rear view showing the jetting direction of each nozzle in the first embodiment. [Figure 12] FIG. 10 is a plan view showing the jetting direction of each nozzle of a first modified example of the first embodiment. [Figure 13] FIG. 10 is a cross-sectional view of a nozzle head according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, various embodiments of the nozzle head of the present invention will be described with reference to FIGS.

[0013] First Embodiment (overview) The nozzle head of the first embodiment is a nozzle head that has a nozzle that sprays pressurized water in a spray direction so as to form a water jet that collides with an object and scrapes off part of the object, and is driven to rotate around a first central axis.

[0014] The nozzle head has four nozzles: a first nozzle, a second nozzle, a third nozzle, and a fourth nozzle. A straight line extending along the first ejection direction, which is the ejection direction of the first nozzle, and a straight line extending along the second ejection direction, which is the ejection direction of the second nozzle, intersect at a first intersection position. A straight line extending along the third ejection direction, which is the ejection direction of the third nozzle, and a straight line extending along the fourth ejection direction, which is the ejection direction of the fourth nozzle, intersect at a second intersection position. The first intersection position and the second intersection position are located on a first reference plane, which is a plane including the first central axis. The straight line along the first ejection direction and the straight line along the second ejection direction extend along the first reference plane or are plane-symmetrical to each other with respect to the first reference plane. The straight line along the third ejection direction and the straight line along the fourth ejection direction extend along the first reference plane or are plane-symmetrical to each other with respect to the first reference plane.

[0015] According to this, the line along the first injection direction and the line along the second injection direction extend along the first reference plane or are plane-symmetrical with respect to each other with respect to the first reference plane. Furthermore, the line along the third injection direction and the line along the fourth injection direction also extend along the first reference plane or are plane-symmetrical with respect to each other with respect to the first reference plane.

[0016] This prevents the reaction forces generated by spraying water from the first and second nozzles and the reaction forces generated by spraying water from the third and fourth nozzles from generating a rotational moment that tends to rotate the nozzle head around the central axis of rotation. As a result, the rotational speed of the nozzle head can be controlled with high precision, and the shape of the portion to be scraped off from the target object can be controlled with high precision. Next, the nozzle head of the first embodiment will be described in more detail.

[0017] (composition) A water jet apparatus 1 equipped with a nozzle head of the first embodiment will be described below using a right-handed Cartesian coordinate system having an x-axis, a y-axis, and a z-axis as shown in Figures 1 to 11. Note that in this specification, a similar coordinate system is also used in Figures 12 and 13 described later.

[0018] In this example, the x-axis direction, y-axis direction, and z-axis direction may be respectively represented as the left-right direction of the water jet apparatus 1, the front-rear direction of the water jet apparatus 1, and the up-down direction of the water jet apparatus 1. Also, in this example, the positive x-axis direction, negative x-axis direction, positive y-axis direction, negative y-axis direction, positive z-axis direction, and negative z-axis direction may be respectively represented as the rightward direction of the water jet apparatus 1, the leftward direction of the water jet apparatus 1, the frontward direction of the water jet apparatus 1, the rearward direction of the water jet apparatus 1, the upward direction of the water jet apparatus 1, and the downward direction of the water jet apparatus 1. In this example, the z-axis direction coincides with the horizontal direction, but the z-axis direction may coincide with a direction other than the horizontal direction depending on how the water jet apparatus 1 is used.

[0019] As shown in FIG. 1, the water jet apparatus 1 includes a swivel joint 10, a head holder 20, and a nozzle head 30.

[0020] In this example, the water jet apparatus 1 generates a water jet and strikes the target object with the water jet. This causes the water jet apparatus 1 to carve away a portion of the target object, forming a hole in the target object. For example, the target object may be bedrock or concrete. The water jet apparatus 1 may also include a moving device that moves the swivel joint 10, head holder 20, and nozzle head 30 in the z-axis direction.

[0021] The water jet apparatus 1 may also be used to form a groove in an object by scraping away a portion of the object. The water jet apparatus 1 may also be used to scrape away the surface of an object. For example, the water jet apparatus 1 may be used to chip rock, concrete, or the like. In this case, the water jet apparatus 1 may include a moving device that moves the swivel joint 10, head holder 20, and nozzle head 30 along a plane perpendicular to the z-axis.

[0022] Fig. 1 is a view of the water jet apparatus 1 as seen from the rear of the water jet apparatus 1 (in other words, a rear view). Fig. 2 is a view of the nozzle head 30 as seen from a position to the right of the nozzle head 30, behind the nozzle head 30, and above the nozzle head 30 (in other words, a right-rear-upper perspective view). Fig. 3 is a view of the nozzle head 30 as seen from a position to the left of the nozzle head 30, behind the nozzle head 30, and below the nozzle head 30 (in other words, a left-rear-lower perspective view).

[0023] Fig. 4 is a diagram of the nozzle head 30 as seen from behind the nozzle head 30 (in other words, a back view). Fig. 5 is a diagram of the nozzle head 30 as seen from above the nozzle head 30 (in other words, a plan view). Fig. 6 is a diagram of a cross section of the nozzle head 30 cut by a plane represented by line VI-VI in Fig. 5 as seen in the negative direction of the x-axis.

[0024] Fig. 7 is a right-rear-upper perspective view of the disassembled nozzle head 30. Fig. 8 is a left-rear-lower perspective view of the disassembled nozzle head 30. Fig. 9 is a plan view of the nozzle head 30, with the straight lines along the spray direction of each nozzle indicated by dotted lines.

[0025] Fig. 10 is a view of the nozzle head 30 as seen from the right of the nozzle head 30 (in other words, a right side view), in which straight lines along the jetting direction of each nozzle are represented by dotted lines and hidden lines are represented by dashed lines. Fig. 11 is a rear view of the nozzle head 30, in which straight lines along the jetting direction of each nozzle are represented by dotted lines and hidden lines are represented by dashed lines.

[0026] As shown in FIG. 1, the swivel joint 10 includes a fixed part 11 and a rotating part 12. The fixed portion 11 has a cylindrical shape with a central axis extending in the z-axis direction. The rotating part 12 is cylindrical with a central axis extending in the z-axis direction. The central axis of the rotating part 12 is located on the same straight line as the central axis of the fixed part 11. In this example, the diameter of the rotating part 12 is smaller than the diameter of the fixed part 11. However, the diameter of the rotating part 12 may be equal to the diameter of the fixed part 11.

[0027] Rotating portion 12 constitutes the end portion of swivel joint 10 in the positive direction of the z-axis. Rotating portion 12 is rotatable relative to fixed portion 11 around the central axis of rotating portion 12, and the end portion of rotating portion 12 in the negative direction of the z-axis is fixed to fixed portion 11.

[0028] The swivel joint 10 has a flow path that penetrates the swivel joint 10 in the z-axis direction. A hose that supplies pressurized water is connected to the end of the swivel joint 10 in the negative z-axis direction. As a result, water flowing through the hose flows into the flow path of the swivel joint 10. The swivel joint 10 may also be referred to as a rotary joint.

[0029] The head holder 20 is cylindrical with a central axis extending in the z-axis direction. The central axis of the head holder 20 is located on the same straight line as the central axis of the fixed part 11 and the central axis of the rotating part 12. In this example, the diameter of the head holder 20 is equal to the diameter of the fixed part 11. However, the diameter of the head holder 20 may be larger than the diameter of the fixed part 11.

[0030] The head holder 20 has a flow path that penetrates the head holder 20 in the z-axis direction. The flow path of the head holder 20 communicates with the flow path of the swivel joint 10. As a result, water that flows into the flow path of the swivel joint 10 flows into the flow path of the head holder 20.

[0031] The head holder 20 is fixed to the rotating part 12 at an end thereof in the negative direction of the z axis so as to be unrotatable relative to the rotating part 12 . The head holder 20 is driven to rotate around the central axis of the head holder 20 by a rotation drive device (not shown). For example, the rotation drive device includes an electric motor or a hydraulic motor.

[0032] 1 to 8, the nozzle head 30 includes a main body 31, a head cover 32, and four nozzles 331 to 334. The four nozzles 331 to 334 include a first nozzle 331, a second nozzle 332, a third nozzle 333, and a fourth nozzle 334.

[0033] As shown in FIGS. 2 to 8, the main body 31 includes a large diameter portion 311 and a small diameter portion 312. The large diameter portion 311 is cylindrical with a central axis extending in the z-axis direction. The central axis of the large diameter portion 311 is aligned with the central axis of the head holder 20. In this example, the diameter of the large diameter portion 311 is equal to the diameter of the head holder 20.

[0034] Small diameter portion 312 is cylindrical with a central axis extending in the z-axis direction. The central axis of small diameter portion 312 is aligned on the same straight line as the central axis of large diameter portion 311. In this example, the diameter of small diameter portion 312 is smaller than the diameter of large diameter portion 311. Small diameter portion 312 extends in the negative z-axis direction from the end face of large diameter portion 311 facing in the negative z-axis direction.

[0035] The small diameter portion 312 is accommodated in a hole (not shown) that opens at the end face of the head holder 20 in the positive direction of the z axis, and is thereby fixed to the head holder 20 so as not to be rotatable relative to the head holder 20. In this example, the outer peripheral surface of the small diameter portion 312 has a male thread. Furthermore, the inner peripheral surface of the hole in the head holder 20 has a female thread. The small diameter portion 312 is fixed to the head holder 20 by the male thread and the female thread being screwed together.

[0036] With this configuration, the nozzle head 30 is rotated integrally with the head holder 20 around the central axis of the nozzle head 30. In this example, the central axis of the nozzle head 30 (in other words, the central axis of rotation of the nozzle head 30) corresponds to the first central axis.

[0037] 6, 10, and 11, the main body 31 has a main flow path 31a, which is a flow path that opens at an end face of the main body 31 in the negative direction of the z axis. The main flow path 31a of the main body 31 communicates with the flow path of the head holder 20 at the end in the negative direction of the z axis. As a result, water that has flowed into the flow path of the head holder 20 flows into the main flow path 31a of the main body 31.

[0038] The main body 31 has four nozzle accommodating holes 31b1 to 31b4 that open at the end face of the main body 31 facing in the positive direction of the z-axis and that respectively accommodate the four nozzles 331 to 334. The four nozzle accommodating holes 31b1 to 31b4 consist of a first nozzle accommodating hole 31b1, a second nozzle accommodating hole 31b2, a third nozzle accommodating hole 31b3, and a fourth nozzle accommodating hole 31b4.

[0039] The main body 31 has four branch flow paths 31c1 to 31c4 that respectively connect the main flow path 31a and the four nozzle housing holes 31b1 to 31b4. The four branch flow paths 31c1 to 31c4 consist of a first branch flow path 31c1, a second branch flow path 31c2, a third branch flow path 31c3, and a fourth branch flow path 31c4. The cross section of each of the branch flow paths 31c1 to 31c4 is circular.

[0040] Each of branch channels 31c1 to 31c4 communicates with main channel 31a at the end in the negative direction of the z axis, so that water that has flowed into main channel 31a flows into each of branch channels 31c1 to 31c4.

[0041] The first nozzle 331 has a first internal flow path 331a that is a flow path that penetrates the first nozzle 331 in a first ejection direction, which is the ejection direction of the first nozzle 331. The cross section of the first internal flow path 331a is circular. In other words, the first internal flow path 331a has a central axis that extends along the first ejection direction.

[0042] The first internal flow path 331a communicates with the first branch flow path 31c1 at an end of the first internal flow path 331a in the upstream direction of the first ejection direction. The diameter of the cross section of the first internal flow path 331a at the end in the upstream direction of the first ejection direction is equal to the diameter of the cross section of the first branch flow path 31c1.

[0043] The cross-sectional area of ​​the first internal flow path 331a gradually decreases downstream in the first ejection direction, thereby forming a throttle portion at the end of the first internal flow path 331a in the downstream direction of the first ejection direction. The diameter of the cross section of the first internal flow path 331a at the end in the downstream direction of the first ejection direction is smaller than the diameter of the cross section of the first internal flow path 331a at the end in the upstream direction of the first ejection direction.

[0044] The first nozzle 331 is fixed to the main body 31 so that it cannot rotate relative to the main body 31, by having the portion of the first nozzle 331 other than the end portion downstream of the first ejection direction accommodated in the first nozzle accommodating hole 31b1.

[0045] In this example, the housing portion, which is the portion of the first nozzle 331 other than the end portion in the downstream direction of the first ejection direction, is cylindrical with a central axis extending along the first ejection direction. Also, in this example, the first nozzle accommodating hole 31b1 is cylindrical with a central axis extending along the first ejection direction. The outer peripheral surface of the housing portion has a male thread. Furthermore, the inner peripheral surface of the first nozzle accommodating hole 31b1 has a female thread. The first nozzle 331 is fixed to the main body 31 by threading the male thread into the female thread.

[0046] The second nozzle 332, the third nozzle 333, and the fourth nozzle 334 have a second internal flow path 332a, a third internal flow path 333a, and a fourth internal flow path 334a, respectively, similar to the first internal flow path 331a in the first nozzle 331. The second internal flow path 332a, the third internal flow path 333a, and the fourth internal flow path 334a communicate with a second branch flow path 31c2, a third branch flow path 31c3, and a fourth branch flow path 31c4, respectively, similar to the first branch flow path 31c1 for the first internal flow path 331a.

[0047] The second nozzle 332, the third nozzle 333, and the fourth nozzle 334 are accommodated in the second nozzle accommodating hole 31b2, the third nozzle accommodating hole 31b3, and the fourth nozzle 334, respectively, in the same manner as the first nozzle accommodating hole 31b1 for the first nozzle 331, and are thereby fixed to the main body 31 so as not to be rotatable relative to the main body 31.

[0048] With this configuration, pressurized water supplied by the hose connected to the swivel joint 10 is sprayed from each of the nozzles 331 to 334. The water sprayed from each of the nozzles 331 to 334 forms a water jet. The positions and ejection directions of the nozzles 331 to 334 will be described later.

[0049] 2 to 8, the head cover 32 constitutes the end portion of the nozzle head 30 in the positive direction of the z-axis. The head cover 32 includes a disk portion 321 and a plurality of (two in this example) key portions 322. The number of key portions 322 included in the head cover 32 may be one, or three or more.

[0050] The disk portion 321 is disk-shaped with a central axis extending in the z-axis direction. The central axis of the disk portion 321 is located on the same straight line as the central axes of the large diameter portion 311 and the small diameter portion 312. In this example, the diameter of the disk portion 321 is equal to the diameter of the large diameter portion 311.

[0051] Key portion 322 extends in the negative direction of the z axis from the end face of disk portion 321 facing in the negative direction of the z axis at the outer edge of disk portion 321. Multiple key portions 322 are spaced apart from one another in the circumferential direction of disk portion 321.

[0052] As shown in Figures 7 and 8, large diameter portion 311 has a plurality of key grooves 311a, into which a plurality of key portions 322 are respectively fitted, at the end of the outer peripheral surface of large diameter portion 311 in the positive direction of the z axis. 2 to 4, the head cover 32 is fixed to the main body 31 such that the disk portion 321 covers the end face of the main body 31 in the positive direction of the z axis, with the multiple key portions 322 fitted into the multiple key groove portions 311a, respectively. This fixes the head cover 32 to the main body 31 so that it cannot rotate relative to the main body 31.

[0053] With this configuration, the head cover 32 covers the four nozzles 331 to 334 at the end of the nozzle head 30 in the positive direction of the z axis (in other words, the tip of the nozzle head 30).

[0054] The head cover 32 is removably fixed to the main body 31. In this example, the head cover 32 is removably fixed to the main body 31 by screws (not shown).

[0055] 2 and 6 to 8, the disk portion 321 has four injection holes 321a1 to 321a4 that penetrate the disk portion 321 in the z-axis direction. The four injection holes 321a1 to 321a4 include a first injection hole 321a1, a second injection hole 321a2, a third injection hole 321a3, and a fourth injection hole 321a4.

[0056] The first injection hole 321a1, the second injection hole 321a2, the third injection hole 321a3, and the fourth injection hole 321a4 allow the water injected from the first nozzle 331, the second nozzle 332, the third nozzle 333, and the fourth nozzle 334 to pass through, respectively.

[0057] Here, the positions and jetting directions of the nozzles 331 to 334 will be explained. 9 to 11, a line D1 extending along the first ejection direction, which is the ejection direction of the first nozzle 331, and a line D2 extending along the second ejection direction, which is the ejection direction of the second nozzle 332, intersect at a first intersection position X1. Also, a line D3 extending along the third ejection direction, which is the ejection direction of the third nozzle 333, and a line D4 extending along the fourth ejection direction, which is the ejection direction of the fourth nozzle 334, intersect at a second intersection position X2.

[0058] The first intersection position X1 and the second intersection position X2 are located on a first reference plane RP1 which is a plane including the central axis of the nozzle head 30. 9, in this example, when projected onto a plane perpendicular to the z axis, the distance from the central axis of the nozzle head 30 to the first intersection position X1 and the distance from the central axis of the nozzle head 30 to the second intersection position X2 are equal to each other. Note that when projected onto a plane perpendicular to the z axis, the distance from the central axis of the nozzle head 30 to the first intersection position X1 and the distance from the central axis of the nozzle head 30 to the second intersection position X2 may be slightly different.

[0059] 10 and 11, in this example, the position of the first intersecting position X1 in the z-axis direction is equal to the position of the second intersecting position X2 in the z-axis direction. Note that the position of the first intersecting position X1 in the z-axis direction and the position of the second intersecting position X2 in the z-axis direction may be slightly different.

[0060] 9 and 11, in this example, a straight line D1 along the first ejection direction and a straight line D2 along the second ejection direction extend along a first reference plane RP1. Note that the straight line D1 along the first ejection direction and the straight line D2 along the second ejection direction may be plane-symmetrical to each other with respect to the first reference plane RP1.

[0061] 9, in this example, the downstream end of the first internal flow path 331a of the first nozzle 331 in the first ejection direction (in other words, the first ejection port) is located on the positive side of the y-axis relative to the central axis of the nozzle head 30. Furthermore, the downstream end of the second internal flow path 332a of the second nozzle 332 in the second ejection direction (in other words, the second ejection port) is located on the negative side of the y-axis relative to the central axis of the nozzle head 30.

[0062] 9 and 11, in this example, the line D3 along the third ejection direction and the line D4 along the fourth ejection direction are plane-symmetric with each other with respect to the first reference plane RP1. Note that the line D3 along the third ejection direction and the line D4 along the fourth ejection direction may extend along the first reference plane RP1.

[0063] 9, in this example, the downstream end of the third internal flow path 333a of the third nozzle 333 in the third injection direction (in other words, the third injection port) is located on the positive side of the x-axis relative to the first reference plane RP1. Also, the downstream end of the fourth internal flow path 334a of the fourth nozzle 334 in the fourth injection direction (in other words, the fourth injection port) is located on the negative side of the x-axis relative to the first reference plane RP1. In this example, the distance from the first reference plane RP1 to the third injection nozzle and the distance from the first reference plane RP1 to the fourth injection nozzle are equal to each other.

[0064] 10, in this example, the second nozzle 332 is configured so that the water jet formed by the second nozzle 332 penetrates a second reference plane RP2. The second reference plane RP2 is a plane that includes the central axis of the nozzle head 30 and is perpendicular to the first reference plane RP1. In this example, the water jet formed by the second nozzle 332 is water sprayed from the second nozzle 332 and is located in a portion of the nozzle head 30 that is closer to the positive side of the z axis than the end face of the nozzle head 30 that is in the positive direction of the z axis.

[0065] In addition to the second nozzle 332, or instead of the second nozzle 332, the third nozzle 333 and the fourth nozzle 334 may be configured so that the water jets formed by the third nozzle 333 and the fourth nozzle 334 penetrate the second reference plane RP2.

[0066] (operation) Next, the operation of the water jet apparatus 1 of the first embodiment will be described. First, the head holder 20 is rotated by the rotary drive device around the central axis of the head holder 20. As a result, the nozzle head 30 is rotated integrally with the head holder 20 around the central axis of the nozzle head 30.

[0067] Next, pressurized water is supplied to the water jet device 1 via a hose connected to the swivel joint 10. As a result, the pressurized water flows through the flow path of the swivel joint 10, the flow path of the head holder 20, the main flow path 31a of the nozzle head 30, the four branch flow paths 31c1-31c4 of the nozzle head 30, and the internal flow paths 331a-334a of the four nozzles 331-334, and is then sprayed from the four nozzles 331-334.

[0068] As a result, water sprayed from the four nozzles 331-334 forms four water jets. The four water jets collide with the target object and scrape off a portion of the object. In this example, the water jet device 1 is advanced in the depth direction of the hole (in this example, the positive direction of the z-axis) according to the depth of the target hole. The water jet device 1 then arrives at a position according to the depth of the target hole.

[0069] Thereafter, as a result of the object being scraped away, the water jet formed by the water sprayed from first nozzle 331 and the water jet formed by the water sprayed from second nozzle 332 intersect, and the water jet formed by the water sprayed from third nozzle 333 and the water jet formed by the water sprayed from fourth nozzle 334 intersect. In this state, the water jets do not collide directly with the object, so the object is not scraped away.

[0070] Next, the supply of water through the hose is stopped, and the rotational driving of the head holder 20 by the rotational driving device is stopped. In this way, a hole is formed in the object.

[0071] As described above, the nozzle head 30 of the first embodiment is provided with nozzles (four nozzles 331 to 334 in this example) that spray pressurized water in a spray direction so as to form a water jet that collides with an object and scrapes off a part of the object. The nozzle head 30 is driven to rotate around a first central axis (the central axis of the nozzle head 30 in this example).

[0072] The nozzle head 30 has four nozzles. The four nozzles 331 to 334 are a first nozzle 331, a second nozzle 332, a third nozzle 333, and a fourth nozzle 334. A straight line D1 along the first ejection direction, which is the ejection direction of the first nozzle 331, and a straight line D2 along the second ejection direction, which is the ejection direction of the second nozzle 332, intersect at a first intersection position X1. A straight line D3 extending along the third ejection direction, which is the ejection direction of the third nozzle 333, and a straight line D4 extending along the fourth ejection direction, which is the ejection direction of the fourth nozzle 334, intersect at a second intersection position X2.

[0073] The first intersection position X1 and the second intersection position X2 are located on a first reference plane RP1, which is a plane including the first center axis. The straight line D1 along the first injection direction and the straight line D2 along the second injection direction extend along the first reference plane RP1 or are plane-symmetrical to each other with respect to the first reference plane RP1. The straight line D3 along the third injection direction and the straight line D4 along the fourth injection direction extend along the first reference plane RP1 or are plane-symmetrical to each other with respect to the first reference plane RP1.

[0074] According to this, the straight line D1 along the first injection direction and the straight line D2 along the second injection direction extend along the first reference plane RP1 or are plane-symmetrical with respect to each other with respect to the first reference plane RP1. Furthermore, the straight line D3 along the third injection direction and the straight line D4 along the fourth injection direction also extend along the first reference plane RP1 or are plane-symmetrical with respect to each other with respect to the first reference plane RP1.

[0075] This makes it possible to suppress the generation of a rotational moment that tends to rotate the nozzle head 30 around the central axis of rotation due to the reaction forces generated by spraying water from the first nozzle 331 and the second nozzle 332 and the reaction forces generated by spraying water from the third nozzle 333 and the fourth nozzle 334. As a result, the rotational speed of the nozzle head 30 can be controlled with high precision, and the shape of the portion to be scraped off from the target object can be controlled with high precision.

[0076] Furthermore, the nozzle head 30 of the first embodiment is configured so that the water jet formed by at least one nozzle (in this example, the second nozzle 332) among the four nozzles 331 to 334 penetrates a second reference plane RP2, which is a plane that includes the first center axis and is perpendicular to the first reference plane RP1.

[0077] This prevents the area that remains uncut from becoming excessively large near the straight line along the central axis of rotation of the nozzle head 30. As a result, the shape of the portion that is cut off from the target object can be controlled with high precision.

[0078] Furthermore, in the nozzle head 30 of the first embodiment, the straight line D1 along the first ejection direction and the straight line D2 along the second ejection direction extend along the first reference plane RP1. In addition, the straight line D3 along the third ejection direction and the straight line D4 along the fourth ejection direction are plane-symmetrical to each other with respect to the first reference plane RP1.

[0079] This allows the positions of the four nozzles 331 to 334 to be closer to the central axis of rotation of the nozzle head 30. This allows the radial size of the nozzle head 30 to be reduced. As a result, for example, holes with relatively small diameters can be formed with high precision.

[0080] Furthermore, the nozzle head 30 of the first embodiment includes a head cover 32 that covers the nozzles (four nozzles 331 to 334 in this example) at the tip of the nozzle head 30 and is removably fixed.

[0081] The object scraped off by the impact of the water jet may scatter. If the scattered object collides with the nozzles 331-334, there is a risk that the nozzles 331-334 may be damaged. In contrast, with the nozzle head 30, the nozzles 331-334 can be protected by the head cover 32. As a result, damage to the nozzles 331-334 can be suppressed. Furthermore, if the head cover 32 is damaged, it can be easily replaced.

[0082] <First Modification of First Embodiment> Next, a nozzle head according to a first modified example of the first embodiment will be described. The nozzle head according to the first modified example of the first embodiment differs from the nozzle head according to the first embodiment mainly in that the position of each nozzle and the ejection direction are different. The following mainly describes the differences. In the description of the first modified example of the first embodiment, components that are assigned the same reference numerals as those used in the first embodiment are the same or substantially similar components.

[0083] (composition) As shown in Figure 12, in the nozzle head 30A of the first modified example of the first embodiment, as in the nozzle head 30 of the first embodiment, the first intersection position X1 and the second intersection position X2 are located on the first reference plane RP1, which is a plane including the central axis of the nozzle head 30A. FIG. 12 is a plan view of the nozzle head 30A in which the straight lines along the jetting direction of each nozzle are represented by dotted lines.

[0084] In the nozzle head 30A of the first modified example of the first embodiment, as in the nozzle head 30 of the first embodiment, when projected onto a plane perpendicular to the z-axis, the distance from the central axis of the nozzle head 30A to the first intersection position X1 and the distance from the central axis of the nozzle head 30A to the second intersection position X2 are equal to each other.

[0085] In the nozzle head 30A of the first modified example of the first embodiment, as in the nozzle head 30 of the first embodiment, the position of the first intersection position X1 in the z-axis direction and the position of the second intersection position X2 in the z-axis direction are equal to each other.

[0086] In this example, the straight line D1 along the first injection direction and the straight line D2 along the second injection direction are plane-symmetric with respect to the first reference plane RP1. In this example, the downstream end of the first internal flow path 331a of the first nozzle 331 in the first injection direction (in other words, the first injection port) is located on the positive side of the x-axis relative to the first reference plane RP1. Also, the downstream end of the second internal flow path 332a of the second nozzle 332 in the second injection direction (in other words, the second injection port) is located on the negative side of the x-axis relative to the first reference plane RP1.

[0087] In this example, the distance from the first reference plane RP1 to the first jet nozzle and the distance from the first reference plane RP1 to the second jet nozzle are equal to each other, and the first jet nozzle and the second jet nozzle are located in the positive y-axis direction relative to the second reference plane RP2.

[0088] In this example, the straight line D3 along the third injection direction and the straight line D4 along the fourth injection direction are plane-symmetric with respect to the first reference plane RP1. In this example, the downstream end of the third internal flow path 333a of the third nozzle 333 in the third injection direction (in other words, the third injection port) is located on the positive side of the x-axis relative to the first reference plane RP1. Also, the downstream end of the fourth internal flow path 334a of the fourth nozzle 334 in the fourth injection direction (in other words, the fourth injection port) is located on the negative side of the x-axis relative to the first reference plane RP1.

[0089] In this example, the distance from the first reference plane RP1 to the third jet nozzle is equal to the distance from the first reference plane RP1 to the fourth jet nozzle, and the third jet nozzle and the fourth jet nozzle are located in the negative y-axis direction relative to the second reference plane RP2.

[0090] In this example, the straight line D1 along the first injection direction and the straight line D3 along the third injection direction are plane-symmetric with respect to the second reference plane RP2. In this example, the straight line D2 along the second injection direction and the straight line D4 along the fourth injection direction are plane-symmetric with respect to the second reference plane RP2.

[0091] As described above, the nozzle head 30A of the first modified example of the first embodiment is provided with nozzles (four nozzles 331 to 334 in this example) that spray pressurized water in a spray direction so as to form a water jet that collides with an object and scrapes off a part of the object. The nozzle head 30A is driven to rotate about a first central axis (the central axis of the nozzle head 30A in this example).

[0092] The nozzle head 30A has four nozzles 331 to 334. The four nozzles 331 to 334 are a first nozzle 331, a second nozzle 332, a third nozzle 333, and a fourth nozzle 334. A straight line D1 along the first ejection direction, which is the ejection direction of the first nozzle 331, and a straight line D2 along the second ejection direction, which is the ejection direction of the second nozzle 332, intersect at a first intersection position X1. A straight line D3 extending along the third ejection direction, which is the ejection direction of the third nozzle 333, and a straight line D4 extending along the fourth ejection direction, which is the ejection direction of the fourth nozzle 334, intersect at a second intersection position X2.

[0093] The first intersection position X1 and the second intersection position X2 are located on a first reference plane RP1, which is a plane including the first center axis. The straight line D1 along the first injection direction and the straight line D2 along the second injection direction extend along the first reference plane RP1 or are plane-symmetrical to each other with respect to the first reference plane RP1. The straight line D3 along the third injection direction and the straight line D4 along the fourth injection direction extend along the first reference plane RP1 or are plane-symmetrical to each other with respect to the first reference plane RP1.

[0094] According to this, the straight line D1 along the first injection direction and the straight line D2 along the second injection direction extend along the first reference plane RP1 or are plane-symmetrical with respect to each other with respect to the first reference plane RP1. Furthermore, the straight line D3 along the third injection direction and the straight line D4 along the fourth injection direction also extend along the first reference plane RP1 or are plane-symmetrical with respect to each other with respect to the first reference plane RP1.

[0095] This makes it possible to suppress the generation of a rotational moment that tends to rotate nozzle head 30A around the central axis of rotation due to the reaction forces generated by spraying water from first nozzle 331 and second nozzle 332 and the reaction forces generated by spraying water from third nozzle 333 and fourth nozzle 334. As a result, the rotational speed of nozzle head 30A can be controlled with high precision, and the shape of the portion to be scraped off from the target object can be controlled with high precision.

[0096] Furthermore, the nozzle head 30A of the first modified example of the first embodiment includes a head cover 32 that covers the nozzles (four nozzles 331 to 334 in this example) at the tip of the nozzle head 30A and is removably fixed.

[0097] The object scraped off by the collision of the water jet may scatter. If the scattered object collides with the nozzles 331-334, there is a risk that the nozzles 331-334 may be damaged. In contrast, according to the nozzle head 30A, the nozzles 331-334 can be protected by the head cover 32. As a result, damage to the nozzles 331-334 can be suppressed. Furthermore, if the head cover 32 is damaged, it can be easily replaced.

[0098] Second Embodiment Next, a nozzle head of a second embodiment will be described. The nozzle head of the second embodiment differs from the nozzle head of the first embodiment mainly in that it is provided with a nozzle holder for adjusting the position of the nozzle. The following mainly describes the differences. In the description of the second embodiment, components that are assigned the same reference numerals as those used in the first embodiment are the same or substantially similar components.

[0099] (composition) As shown in FIG. 13, the nozzle head 30B of the second embodiment differs from the nozzle head 30 of the first embodiment in that it includes a nozzle holder 31e1 and a nozzle holder accommodating hole 31d1 instead of the first nozzle accommodating hole 31b1. FIG. 13 is a cross-section of the nozzle head 30B taken along the first reference plane RP1, viewed in the negative direction of the x-axis.

[0100] In this example, the main body 31 has a nozzle holder accommodating hole 31d1 that opens at the end face of the main body 31 in the positive direction of the z axis and accommodates the nozzle holder 31e1. The nozzle holder accommodating hole 31d1 is cylindrical with a central axis extending along the first reference direction. The nozzle holder 31e1 is also cylindrical with a central axis extending along the first reference direction. The central axis of the nozzle holder 31e1 is aligned with the central axis of the nozzle holder accommodating hole 31d1.

[0101] When accommodated in the nozzle holder accommodation hole 31d1, the nozzle holder 31e1 is fixed to the main body 31 so that the rotational position of the nozzle holder 31e1 around the central axis can be adjusted. In this example, the outer peripheral surface of the nozzle holder 31e1 has a male thread. Furthermore, the inner peripheral surface of the nozzle holder accommodation hole 31d1 has a female thread. The nozzle holder 31e1 is fixed to the main body 31 by threading the male thread into the female thread. Furthermore, in this example, a screw (not shown) abuts against the outer peripheral surface of the nozzle holder 31e1, thereby preventing the rotational position of the nozzle holder 31e1 from being changed. In this example, the central axis of the nozzle holder 31e1 corresponds to the second central axis.

[0102] The nozzle holder 31e1 has a first nozzle receiving hole 31e1a that opens at the end face of the nozzle holder 31e1 in the positive direction of the z axis and receives the first nozzle 331 therein.

[0103] The first nozzle accommodating hole 31e1a is cylindrical and has a central axis extending parallel to the central axis of the nozzle holder 31e1 at a position separated by an offset distance from the central axis of the nozzle holder 31e1. In other words, the first nozzle accommodating hole 31e1a is a hole in which the first nozzle 331 is fixed so that the first ejection direction extends parallel to the central axis of the nozzle holder 31e1 at a position separated by an offset distance from the central axis of the nozzle holder 31e1.

[0104] The nozzle holder 31e1 has a connecting flow path 31e1b that is connected to the first branch flow path 31c1 at the end of the nozzle holder 31e1 in the negative direction of the z-axis, and is connected to the first internal flow path 331a at the end of the first internal flow path 331a of the first nozzle 331 upstream of the first injection direction. In this example, the cross section of the connection flow path 31e1b is circular, and the diameter of the cross section of the connection flow path 31e1b is equal to the diameter of the cross section of the first branch flow path 31c1.

[0105] With this configuration, pressurized water supplied by a hose connected to the swivel joint 10 flows into the first branch flow path 31c1, passes through the connecting flow path 31e1b of the nozzle holder 31e1 and the first internal flow path 331a of the first nozzle 331, and is then sprayed from the first nozzle 331.

[0106] As described above, according to the nozzle head 30B of the second embodiment, the same actions and effects as those of the nozzle head 30 of the first embodiment can be achieved. Furthermore, the nozzle head 30B of the second embodiment includes a nozzle holder 31e1 whose rotational position around a second central axis (in this example, the central axis of the nozzle holder 31e1) is adjustable. The nozzle holder 31e1 has a first nozzle accommodating hole 31e1a to which the first nozzle 331 is fixed at a position spaced an offset distance from the second central axis so that the first ejection direction extends parallel to the second central axis.

[0107] According to this, even if the two water jets formed by the two nozzles (in this example, the first nozzle 331 and the second nozzle 332) do not intersect due to manufacturing errors, for example, the two water jets can be made to intersect by adjusting the rotational position around the second central axis of the nozzle holder 31e1 to which the first nozzle 331 is fixed.

[0108] In a modification of the second embodiment, the nozzle head 30B may include a nozzle holder for the second nozzle 332 instead of the first nozzle 331. Furthermore, in a modification of the second embodiment, the nozzle head 30B may include a nozzle holder for the third nozzle 333 or the fourth nozzle 334 instead of the first nozzle 331 or in addition to the first nozzle 331.

[0109] The nozzle head 30B preferably includes a nozzle holder for one of the two nozzles that form the two intersecting water jets, but may also include nozzle holders for both of the two nozzles that form the two intersecting water jets.

[0110] In addition, in a modification of the second embodiment, the number of nozzles provided in the nozzle head 30B may be 2. In addition, in a modification of the second embodiment, the number of nozzles provided in the nozzle head 30B may be an even number equal to or greater than 6.

[0111] The present invention is not limited to the above-described embodiment. For example, various modifications that can be understood by those skilled in the art may be made to the above-described embodiment without departing from the spirit of the present invention.

[0112] For example, the water jetted from the water jet apparatus 1 may contain additives, such as at least one of an abrasive, a thickener, a surfactant, a rust inhibitor, a corrosion inhibitor, a dye, a pH adjuster, and an antifoaming agent. [Explanation of symbols]

[0113] 1 Water jet equipment 10 Swivel joint 11 Fixed part 12 Rotating part 20 Head holder 30, 30A, 30B nozzle head 31 Main Unit 311 Large diameter section 311a Key groove 312 Small diameter section 31a Main channel 31b1 First nozzle receiving hole 31b2 Second nozzle receiving hole 31b3 Third nozzle receiving hole 31b4 Fourth nozzle receiving hole 31c1 First branch flow path 31c2 Second branch flow path 31c3 Third branch flow path 31c4 4th branch channel 31d1 Nozzle holder accommodation hole 31e1 Nozzle holder 31e1a First nozzle receiving hole 31e1b Connecting channel 32 Headcover 321 Disc Club 321a1 1st injection hole 321a2 2nd injection hole 321a3 3rd injection hole 321a4 4th injection hole 322 Key section 331 No. 1 nozzle 331a First internal flow path 332 Second Nozzle 332a Second internal flow path 333 Third Nozzle 333a Third internal channel 334 4th nozzle 334a Fourth internal channel RP1 1st reference plane RP2 2nd reference plane X1 First intersection point X2 2nd intersection position

Claims

1. a nozzle head including a nozzle for ejecting pressurized water in an ejection direction so as to form a water jet that collides with an object and scrapes off a part of the object, the nozzle head being rotationally driven about a first central axis, four of the nozzles; the four nozzles include a first nozzle, a second nozzle, a third nozzle, and a fourth nozzle; a straight line along a first ejection direction that is the ejection direction of the first nozzle and a straight line along a second ejection direction that is the ejection direction of the second nozzle intersect at a first intersection position; a straight line extending along a third ejection direction that is the ejection direction of the third nozzle and a straight line extending along a fourth ejection direction that is the ejection direction of the fourth nozzle intersect at a second intersection position; the first intersection position and the second intersection position are located on a first reference plane which is a plane including the first central axis, and are located on opposite sides of a second reference plane which is a plane including the first central axis and perpendicular to the first reference plane, the straight line along the first ejection direction and the straight line along the second ejection direction extend along the first reference plane or are plane-symmetric with each other with respect to the first reference plane, A nozzle head, wherein the straight line along the third ejection direction and the straight line along the fourth ejection direction extend along the first reference plane or are plane-symmetrical to each other with respect to the first reference plane.

2. The nozzle head according to claim 1, A nozzle head configured such that a water jet formed by at least one of the four nozzles penetrates the second reference plane.

3. The nozzle head according to claim 1 or 2, a straight line along the first ejection direction and a straight line along the second ejection direction extend along the first reference plane, a straight line extending along the third ejection direction and a straight line extending along the fourth ejection direction are plane-symmetric with respect to the first reference plane;

4. The nozzle head according to claim 1 or 2, a nozzle holder whose rotational position around the second central axis is adjustable; The nozzle holder has a hole in which the nozzle is fixed at a position spaced an offset distance from the second central axis so that the jetting direction extends parallel to the second central axis.

5. The nozzle head according to claim 1 or 2, The nozzle head includes a head cover that covers the nozzle at the tip of the nozzle head and is removably fixed.

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