Piping structure of machine tools

Abstract

The objective is to provide a piping structure for machine tools that can achieve miniaturization and weight reduction of the structure while preventing shearing of the piping hoses. [Solution] The piping structure comprises a fixed part 1a having a mounting part 7 that can be attached to a mounting part 3a of the spindle ram 3 of a machining center M, and a frame 2 that is pivotably attached to the fixed part 1a at the end of the fixed part 1a opposite to the mounting part 7, with the C-axis as the axis of rotation in the direction of connection between the mounting part 7 and the mounting part 3a. Inside the spindle attachment 1, piping hoses 8, 8, 8, 8, which can carry fluid, are arranged to connect an inlet 9 provided at the end of the fixed part 1a on the mounting part 7 side and an outlet 10 provided at the top of the frame 2. The inlet hoses are connected to the inlet 9 via one corresponding fixed part side joint 11 and the outlet hoses are connected to the outlet 10 via one corresponding rotating part side joint 12, and the fixed part side joint 11 is pivotable.

Description

Technical Field

[0001] The present disclosure relates to a piping structure of a machine tool disposed inside a structure having a rotatable rotating part, such as a swivel spindle attachment.

Background Art

[0002] An example of a structure having a rotatable rotating part is a replaceable spindle head in a machine tool. For example, in a replaceable spindle head (hereinafter referred to as a spindle attachment), as disclosed in Patent Document 1, there is a mechanism in which the spindle can rotate around a so-called C-axis, which is the connection direction between the spindle attachment and the machine tool body, as a rotation axis. Even in such a spindle attachment, for purposes such as driving and improving machining accuracy, it is necessary to circulate various fluids such as air, oil, and cutting fluid from the machine tool body side toward the spindle side. Therefore, a spindle attachment having a rotation axis such as the C-axis of Patent Document 1 needs to have a piping structure inside that can withstand the rotation of the spindle around the rotation axis. As a conventional piping structure that can withstand the rotation of the spindle around the rotation axis, there is a method in which a piping hose is passed around the rotation axis and the piping hose can be twisted in accordance with the rotation of the spindle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, simply passing the piping hose through the swivel axis is insufficient, as the rotation of the spindle can cause the hose to twist, potentially leading to shearing due to the torsional load. To prevent this, the piping hose is made longer than a certain length to allow it to follow the rotation of the spindle. On the other hand, if the rotation angle of the spindle is large, the piping hose placed inside the spindle attachment needs to be made even longer. This necessitates increasing the overall size of the spindle attachment to accommodate the longer piping hose, which ultimately reduces the dynamic performance of the spindle.

[0005] Other piping structures capable of withstanding the rotation of the main shaft on a pivot axis include, for example, a rotary joint that bundles multiple piping hoses together, and a so-called cable chain that guides the piping hoses. However, both rotary joints and cable chains are generally bulky structures. Therefore, regardless of which method is used, the challenge of increasing the overall size of the main shaft attachment remains, similar to the challenge of increasing the length of the piping hoses.

[0006] Therefore, the purpose of this disclosure is to provide a piping structure for machine tools that can achieve miniaturization and weight reduction of the structure while preventing shearing of the piping hose. [Means for solving the problem]

[0007] To solve the above problems, a first aspect of the present disclosure is a structure comprising: a fixed part having a mounting part that can be attached to a predetermined part to be attached in a machine tool; and a rotating part that is pivotably attached to the fixed part at the end of the fixed part opposite to the mounting part, with the direction of connection between the mounting part and the part to be attached as the axis of rotation, wherein at least one piping hose capable of carrying fluid is arranged to connect the end of the fixed part on the mounting part side and a predetermined location of the rotating part, the piping hose is connected to the end of the fixed part via one corresponding fixed part side joint and to a predetermined location of the rotating part via one corresponding rotating part side joint, and at least one of the fixed part side joint and the rotating part side joint is pivotable. Another aspect of the first configuration of the present disclosure is characterized in that, in the above configuration, at least one of the swivelable fixed-side joint and the rotating-side joint has a swivel axis that is parallel to the rotation axis of the rotating part. Another aspect of the first configuration of the present disclosure is characterized in that, in the above configuration, the fixed-side joint and the rotating-side joint are arranged on the same circumference with respect to the rotation axis of the rotating part when there are two or more piping hoses. Another aspect of the first configuration of the present disclosure is characterized in that, in the above configuration, the fixed portion or the rotating portion is bent near the connection point with the rotating portion and connects to the fixed portion or the rotating portion in a direction different from the rotation axis direction of the rotating portion. [Effects of the Invention]

[0008] According to this disclosure, at least one of the fixed-side joint connecting the fixed-side part to the fixed-side end of the piping hose, and the rotating-side joint connecting the rotating-side part to the rotating-side end of the piping hose, is rotatable. As a result, the piping hose itself can rotate in accordance with the rotation of the rotating-side part, thereby eliminating twisting of the piping hose caused by the rotation of the rotating-side part and preventing shearing of the piping hose. Furthermore, the pivot axes of the swivelable fixed-side joint and the rotating-side joint are arranged to be parallel to the rotation axis of the rotating part. In addition, if there are two or more piping hoses, at least one of the fixed-side joint and the rotating-side joint is arranged on the same circumference centered on the rotation axis of the rotating part. This makes it possible to suppress the generation of torsional loads in each piping hose, even if entanglement occurs between multiple piping hoses when the rotating part is swiveled. In addition, by connecting the fixed or rotating part to the fixed or rotating end of the piping hose in a direction different from the rotation axis of the rotating part, the expansion and contraction of the piping hoses due to entanglement can be absorbed, and the load generated in each piping hose can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram showing a part of a machine tool equipped with a spindle attachment that has a rotatable rotating part. [Figure 2] This is an explanatory diagram showing the piping structure of the present disclosure when the rotating part is not rotating. [Figure 3] This is an explanatory diagram showing the piping structure when the rotating part is in a swiveling position. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is an explanatory diagram showing a part of a machine tool equipped with a spindle attachment that has a rotatable rotating part. As shown in Figure 1, the machining center M, as a machine tool, has a saddle 5 mounted on a cross rail 4 so as to be movable in the left-right direction along the Y-axis. A spindle ram 3 is supported at the lower end of the saddle 5 so as to be movable in the up-down direction along the Z-axis. Furthermore, a spindle attachment 1 is detachably attached to the lower end of the spindle ram 3.

[0011] The spindle attachment 1 is mounted by inserting a mounting portion 7, which is provided on the fixed portion 1a at the end facing the spindle ram 3, into a mounting portion 3a formed at the lower end of the spindle ram 3. The spindle attachment 1 also has a frame 2 at its lower end, the end opposite to the mounting portion 7, which is a rotating portion that can pivot around the C axis, which is parallel to the Z axis relative to the spindle ram 3. The frame 2 is equipped with a spindle head 6 which has a spindle 6a that holds the tool 6b.

[0012] Figure 2 is an explanatory diagram showing the piping structure of this disclosure when the rotating part is not rotating. As shown in Figure 2, the spindle attachment 1 is equipped with internal piping hoses 8 for circulating various fluids such as air, oil, and cutting fluid, for purposes such as driving and improving machining accuracy. The number of piping hoses 8 corresponds to the number of fluids to be circulated. In this embodiment, assuming that four types of fluids will be circulated in the spindle attachment 1, four piping hoses 8, 8, 8, 8 are arranged to connect the inlet 9 provided in the fixed part 1a and the outlet 10 provided on the upper and lower surfaces of the frame 2.

[0013] The piping hose 8 and the inlet 9 are connected via a fixed-side joint 11. The fixed-side joint 11 is rotatable around the axis of rotation of the frame 2, i.e., the axis of rotation parallel to the C-axis. Furthermore, via the fixed-side joint 11, the four piping hoses 8, 8, 8, 8 are arranged on the same circumference centered on the C axis. The piping hose 8 and the outlet section 10 are connected via a roughly L-shaped rotating section side joint 12. In this embodiment, because the rotating section side joint 12 is roughly L-shaped and the outlet section 10 is on the upper side of the frame 2, the piping hose 8 bends near the outlet section 10 and connects to the rotating section side joint 12, and thus to the frame 2, in a direction different from the C-axis, which is the rotation axis of the frame 2.

[0014] Figure 3 is an explanatory diagram showing the piping structure when the rotating part is in a swiveling position. When the main shaft attachment 1 is not rotating, the piping hoses 8, 8, 8, 8 hang down from the inlet 9 parallel to the C axis from the lower end of the fixed-side joint 11, bend near the outlet 10, and then connect to the rotating-side joint 12, as shown in Figure 2. In this state, no torsional load is generated on the piping hoses 8. On the other hand, when frame 2 rotates 180 degrees around the C axis, the state shown in Figure 3 is achieved. If the fixed-side joint 11 were a non-rotating joint, a corresponding torsional load would be generated in each of the piping hoses 8, 8, 8, 8. However, since the fixed-side joint 11 is rotatable around a rotation axis parallel to the C axis, the fixed-side joint 11, and consequently the piping hoses 8 themselves, can rotate in accordance with the rotation of frame 2. Therefore, the twisting of the piping hoses 8 caused by the rotation of frame 2 can be eliminated, and shearing of the piping hoses 8 can be prevented.

[0015] Furthermore, by arranging the piping hoses 8,8,8,8 on the same circumference centered on the C axis, even if entanglement of the piping hoses 8,8,8,8 occurs due to the rotation of frame 2, the generation of torsional loads in each of the piping hoses 8,8,8,8 can be suppressed.

[0016] In addition, since the connection direction between the swivel part side joint 12 responsible for connecting to the frame 2 and the end of the piping hose 8 on the frame 2 side is different from the C-axis direction, when the frame 2 rotates, the expansion and contraction of the piping hoses 8, 8, 8, 8 due to entanglement between the piping hoses 8, 8, 8, 8 can be absorbed, and the load generated in each of the piping hoses 8, 8, 8, 8 can be reduced.

[0017] The piping structure with the above configuration has a fixed part 1a having a mounting part 7 that can be mounted on the mounted part 3a of the spindle ram 3 in the machining center M, and at the end of the fixed part 1a opposite to the mounting part 7, in the connection direction between the mounting part 7 and the mounted part 3a, that is, with the C-axis as the rotation axis, a frame 2 that is pivotally attached to the fixed part 1a. Inside the spindle attachment 1, piping hoses 8, 8, 8, 8 through which fluid can flow are arranged to connect the inflow part 9 provided at the end of the fixed part 1a on the mounting part 7 side and the outflow part 10 provided at the upper part of the frame 2, and are connected to the inflow part 9 via one corresponding fixed part side joint 11 and to the outflow part 10 via one corresponding swivel part side joint 12, and the fixed part side joint 11 is rotatable.

[0018] Thus, by connecting the inflow part 9 of the fixed part 1a and the end of the piping hose 8 on the fixed part 1a side via a rotatable fixed part side joint 11, the piping hose 8 itself can rotate following the rotation of the frame 2, so that the twist of the piping hose 8 caused by the rotation of the frame 2 can be eliminated and the shear of the piping hose 8 can be prevented.

[0019] Furthermore, by arranging the rotation axis of the fixed part side joint 11 to be parallel to the rotation axis of the frame 2, that is, the C-axis, and arranging the four piping hoses 8, 8, 8, 8 on the same circumference centered on the C-axis via the fixed part side joint 11, when the frame 2 rotates, even if entanglement occurs between the piping hoses 8, 8, 8, 8, the generation of torsional load can be suppressed in each of the piping hoses 8, 8, 8, 8. In addition, by making the connection direction between the rotating joint 12, which is responsible for connecting to the frame 2, and the end of the piping hose 8 on the frame 2 side different from the C-axis direction, the expansion and contraction of the piping hoses 8,8,8,8 caused by entanglement amongst themselves can be absorbed, and the load on each of the piping hoses 8,8,8,8 can be reduced.

[0020] Furthermore, the configuration of the piping structure of this disclosure is not limited in any way to the embodiments described above, and can be modified as necessary without departing from the spirit of the invention. For example, the structure is not limited to a spindle attachment, as long as it includes a rotating part that pivots relative to a fixed part and can accommodate a piping hose internally. Furthermore, the machine tool does not have to be a machining center. Furthermore, a non-swivel joint may be used as the fixed-side joint and a swivel joint as the rotating-side joint, or a swivel joint may be used for both the fixed-side and rotating-side joints. In these cases, in order to encourage the swivel of the piping hose itself, it is desirable that the outlet be located on the upper surface of the upper part of the rotating section, rather than on the lower surface of the upper part of the rotating section as shown in Figure 2. Furthermore, any type of swivelable fixed-side joint and rotating-side joint can be used, as long as the piping hose can be made to swivel. Furthermore, while it is desirable that the fixed part or the rotating part be positioned near the fixed part or rotating part where the piping hose bends, as described in the above embodiment, the arrangement is not limited to this. [Explanation of Symbols]

[0021] 1...Spindle attachment, 1a...Fixed part, 2...Frame (rotating part), 3a...Mounted part, 7...Mounting part, 8...Piping hose, 9...Inlet part, 10...Outlet part, 11...Fixed part side joint, 12...Rotating part side joint, M...Machining center (machine tool).

Claims

1. Within a structure comprising a fixed part having a mounting part that can be attached to a predetermined part to be attached in a machine tool, and a rotating part that is pivotably attached to the fixed part at the end of the fixed part opposite to the mounting part, with the direction of connection between the mounting part and the part to be attached as the axis of rotation, At least one piping hose capable of carrying fluid is arranged to connect the end of the fixed part on the mounting part side with a predetermined location on the rotating part. One of the aforementioned piping hoses is connected to the end of the fixed part via one corresponding fixed-side fitting, and to the predetermined location of the rotating part via one corresponding rotating-side fitting, A piping structure for a machine tool, characterized in that at least one of the fixed-side joint and the rotating-side joint is rotatable.

2. The piping structure for a machine tool according to claim 1, characterized in that at least one of the rotatable fixed-side joint and the rotating-side joint has a pivot axis arranged parallel to the rotation axis of the rotating part.

3. The piping structure for a machine tool according to claim 2, characterized in that, when there are two or more piping hoses, the fixed-side joint and the rotating-side joint are arranged on the same circumference centered on the rotation axis of the rotating part.

4. The piping hose is bent near the connection point with the fixed part or the rotating part, and is connected to the fixed part or the rotating part in a direction different from the rotation axis direction of the rotating part, as described in any one of claims 1 to 3.

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