Tool spindle unit of a machine tool

Abstract

The objective is to provide a tool spindle device that can prevent machining defects even when the fixed clutch is tilted relative to the rotating clutch. [Solution] The tool spindle device M comprises a spindle 1 that is rotatably held with a tool T attached, a piston clutch 7 that is movable in the axial direction of the spindle 1, a rotating clutch 3 fixed to the spindle 1 and rotating together with the spindle 1, and a fixed clutch 4 that is positioned on the same side as the rotating clutch 3 relative to the piston clutch 7 and is fixed to the housing 5 via a fixed member 8. The spindle 1 is prevented from rotating by moving the piston clutch 7 toward the rotating clutch 3 to engage the gears provided on their respective end faces. A gap V is formed between the fixed clutch 4 and the fixed member 8, and an end face groove 10 is formed on the gap V side surface of the fixed clutch 4 between the end face gear 4a of the fixed clutch 4 and the connection part C between the fixed clutch 4 and the fixed member 8.

Description

Technical Field

[0001] The present disclosure relates to a tool spindle device provided in a machine tool.

Background Art

[0002] In the tool spindle device of a machine tool composite machining machine, as a method of stopping (locking) the spindle during turning, a method of engaging the clutch of an end face gear is known. The locking of the spindle by the end face gear clutch is realized by a configuration such as a tool spindle device M1 as shown in, for example, FIG. 3. In addition, since the tool spindle device has axial symmetry centered on the rotation axis of the spindle, in FIGS. 1 to 4 in the present disclosure, symmetric parts are omitted and only a part is shown.

[0003] In the tool spindle device M1, inside the housing 5, the spindle 1 is rotatably supported in a state of holding the tool T by a plurality of angular bearings 2, 2, ···. The spindle 1 has a rotary clutch 3 fixed on its outer circumference. The rotary clutch 3 rotates together with the spindle 1. Further, inside the housing 5, a fixed-side member 8 as a part of the housing 5 is provided, and a fixed-side clutch 4 is attached to the fixed-side member 8. Furthermore, inside the housing 5, a piston clutch 7 is provided so as to be movable in the front-rear direction along the rotation axis L of the spindle 1 and is in a state of being inserted into the flange 6. The rear end face of the piston clutch 7 faces the front end faces of the rotary clutch 3 and the fixed-side clutch 4. End face gears 7a, 3a, 4a having sizes and shapes that mesh with each other are provided on the facing end faces.

[0004] In the tool spindle device M1 described above, the spindle 1 is locked as follows: First, the piston clutch 7 is thrust and moves backward. Then, the end face gear 7a of the moved piston clutch 7 engages with the end face gear 4a of the fixed clutch 4 and the end face gear 3a of the rotating clutch 3, thereby locking the spindle 1. At this time, the thrust applied to the piston clutch 7 must be set to be large enough so that the end face gears 7a, 3a, and 4a do not lift up during machining.

[0005] However, when the spindle 1 is locked, depending on the magnitude of the thrust of the piston clutch 7, the spindle 1 may be displaced backward, which is the direction of movement of the piston clutch 7. Displacement of the spindle 1 that occurs when the spindle 1 is locked can adversely affect machining accuracy. Therefore, in Patent Document 1, the applicant has disclosed a tool spindle position correction device that has the same configuration as the tool spindle device M1 and can effectively prevent the displacement of the spindle due to the thrust of the piston clutch from affecting machining accuracy when the spindle is locked. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-109274 [Overview of the project] [Problems that the invention aims to solve]

[0007] In a spindle locking mechanism like the one described in Patent Document 1, when the piston clutch engages with the stationary clutch and the rotating clutch, the stationary clutch is primarily supported by the piston clutch. This is because the rotating clutch does not restrict the direction of rotation and has low axial rigidity, also known as bearing rigidity. Therefore, if the finishing accuracy or mounting accuracy of the stationary clutch is low, it may negatively affect the engagement between the piston clutch and the rotating clutch. For example, as shown in Figure 4A, suppose the stationary clutch 4 is tilted relative to the rotating clutch 3 due to reasons such as the finishing accuracy or mounting accuracy of the stationary clutch 4. If the spindle 1 is to be locked with the stationary clutch 4 tilted, the piston clutch 7 will engage with the rotating clutch 3 in a tilted position, following the example of the stationary clutch 4, as shown in Figure 4B. In this way, when the piston clutch engages with the rotating clutch 3 in a tilted position and locks, an uneven load is applied to the piston clutch 7, stationary clutch 4, and rotating clutch 3 by an external force transmitted through the spindle 1 during machining. As a result, the tooth surfaces of end gears 7a, 3a, and 4a may deteriorate, causing the gears to lift and potentially leading to machining defects. Furthermore, uneven load on the spindle 1 could cause it to bend, altering the tool tip position and potentially affecting machining accuracy.

[0008] Therefore, the present disclosure aims to provide a tool spindle device that can prevent machining defects even when the fixed clutch is inclined relative to the rotating clutch. [Means for solving the problem]

[0009] To solve the above problems, a first aspect of the present disclosure is a tool spindle device for a machine tool, comprising: a spindle rotatably held within a housing while holding a tool used for machining; a piston clutch movable along the axial direction of the spindle; a rotating clutch fixed to the spindle and rotating together with the spindle; and a fixed clutch positioned on the same side as the rotating clutch and radially outward from the rotating clutch, and fixed to the housing, wherein the piston clutch, the rotating clutch, and the fixed clutch prevent the spindle from rotating by meshing end face gears provided on their opposing end faces, wherein the fixed clutch is fixed to the housing radially outward from the end face gear of the fixed clutch, a gap extending a predetermined distance in the axial direction of the spindle is formed between the end face gear of the fixed clutch and the housing, and an end face groove is formed on the gap-side surface of the fixed clutch between the end face gear of the fixed clutch and the connection portion between the fixed clutch and the housing, thereby reducing the thickness of the fixed clutch along the axial direction of the spindle. Another aspect of the first configuration of the present disclosure is characterized in that, in the above configuration, the gap is formed by a notch. [Effects of the Invention]

[0010] According to this disclosure, by providing a gap and an end face groove in the tool spindle device, the fixed-side clutch can be deformed by utilizing the thrust applied to the piston clutch when the spindle 1 is locked. Therefore, even if the fixed-side clutch is inclined relative to the rotating-side clutch, the fixed-side clutch and the rotating-side clutch can mesh with the end face gear of the piston clutch with the front surface of the end face gear of the fixed-side clutch and the front surface of the end face gear of the rotating-side clutch aligned. Thus, it is possible to prevent the occurrence of machining defects such as gear lifting. Furthermore, it is possible to avoid situations in which the spindle is subjected to uneven load and bends, causing a change in the tool cutting edge position. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing a tool spindle device in this disclosure. [Figure 2]Figure 2A is an explanatory diagram showing the state of the piston clutch, fixed clutch, and rotating clutch in the tool spindle device of this disclosure before locking, and Figure 2B shows the state when locked. [Figure 3] This is a cross-sectional view showing a conventional tool spindle device. [Figure 4] This is an explanatory diagram showing the piston clutch, fixed clutch, and rotating clutch in a conventional tool spindle device in which the fixed clutch is mounted at an angle, with Figure 4A showing the state before locking and Figure 4B showing the state when locked. [Modes for carrying out the invention]

[0012] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is an explanatory diagram showing a cross-section of the tool spindle device of the present disclosure. Figure 2A is an explanatory diagram showing the state of the piston clutch, fixed clutch, and rotating clutch in the tool spindle device of the present disclosure before locking, and Figure 2B is an explanatory diagram showing the state when locked. The explanation of the similar configurations shown in Figures 3 and 4 above will be omitted.

[0013] In the tool spindle device M of the machine tool, as shown in Figure 1, a notch 9 is formed on the front end surface of the fixed-side member 8, extending outward from the inner edge over a predetermined range. This creates a gap V between the fixed-side clutch 4 and the fixed-side member 8. The notch 9 is formed such that its outer edge is at the same level as, or further outward than, the outer edge of the end face gear 4a of the fixed-side clutch 4.

[0014] Furthermore, the tool spindle device M has a concave end face groove 10 formed on the rear end face of the fixed-side clutch 4, between the end face gear 4a of the fixed-side clutch 4 and the connection portion C between the fixed-side clutch 4 and the fixed-side member 8, which reduces the thickness of the fixed-side clutch 4 in the axial direction of the spindle 1. The end face groove 10 is formed in a ring shape and extends around the entire circumference of the fixed-side clutch 4. The inner edge of the end face groove 10 is formed to be at the same level as the outer edge of the end face gear 4a, or to be located inside the outer edge of the end face gear 4a.

[0015] For example, as shown in Figure 2A, suppose the stationary clutch 4 is mounted at an angle to the rotating clutch 3. When the spindle 1 is locked from this state, the end face gear 7a of the piston clutch 7 and the end face gear 4a of the stationary clutch 4 first engage. At this time, due to the notch 9, the thrust applied to the piston clutch 7 pushes the end face gear 4a of the stationary clutch 4 into the gap V at the rear. Furthermore, the end face groove 10 makes the stationary clutch 4 more flexible, starting from the end face groove 10. As a result, as shown in Figure 2B, the end face gear 4a of the stationary clutch 4 is pushed backward and the cross-section deforms into a roughly V-shape, so that the front surface of the end face gear 4a of the stationary clutch 4 and the front surface of the end face gear 3a of the rotating clutch 3 are aligned. Therefore, the end face gear 4a of the stationary clutch 4 and the end face gear 3a of the rotating clutch 3 can engage with the end face gear 7a of the piston clutch 7 while preventing machining defects such as gear lifting.

[0016] In this way, by providing a gap V and an end face groove 10 in the tool spindle device M, the fixed-side clutch 4 can be deformed by utilizing the thrust applied to the piston clutch 7 when the spindle 1 is locked. Therefore, even if the fixed-side clutch 4 is tilted relative to the rotating-side clutch 3, the fixed-side clutch 4 and the rotating-side clutch 3 can mesh with the end face gear 7a of the piston clutch 7 with the front surface of the end face gear 4a of the fixed-side clutch 4 and the front surface of the end face gear 3a of the rotating-side clutch 3 aligned. Thus, it is possible to prevent the occurrence of machining defects such as gear lifting. In addition, it is possible to avoid situations in which the spindle 1 is subjected to an uneven load and bends, causing a change in the tool cutting edge position.

[0017] The configuration of the tool spindle device in 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 shape of the end face groove only needs to facilitate the deformation of the fixed-side clutch, and is not limited to the semicircular cross-section shown in the figure; it may be formed in other shapes such as a triangular cross-section. Also, the gap between the fixed-side clutch and the fixed-side member is not limited to being formed by the notch of the fixed-side member. For example, it may be formed by arranging a spacer between the fixed-side clutch and the fixed-side member. Furthermore, if alignment of the end face gears between the rotating-side clutch due to deformation of the fixed-side clutch is possible, the end face groove and the gap may be provided integrally by notching the fixed-side clutch. In the present disclosure, the fixed-side member is a part of the housing and is shown as a separate body in the above embodiment, but the housing and the fixed-side member may be an integral body. Also, the connection part is not limited to the connection by bolts as shown in the figure, and other connection methods may be used.

Explanation of Reference Numerals

[0018] 1... main shaft, 3... rotating-side clutch, 3a... end face gear, 4... fixed-side clutch, 4a... end face gear, 5... housing, 7... piston clutch, 7a... end face gear, 8... fixed-side member, 9... notch, 10... end face groove, M... machine tool, T... tool, V... gap.

Claims

1. A tool spindle device for a machine tool comprising: a spindle rotatably held within a housing while holding a tool used for machining; a piston clutch movable along the axial direction of the spindle; a rotating clutch fixed to the radially outer surface of the spindle and rotating together with the spindle; and a fixed clutch positioned on the same side as the rotating clutch and radially outward from the rotating clutch, and fixed to the housing, wherein the piston clutch, the rotating clutch, and the fixed clutch prevent the spindle from rotating by meshing end face gears provided on their opposing end faces. The fixed clutch is fixed to the housing radially outward from the end face gear of the fixed clutch. A gap is formed between the end face gear of the fixed clutch and the housing, extending a predetermined distance in the axial direction of the main shaft. A tool spindle device for a machine tool, characterized in that an end face groove is formed on the gap-side surface of the fixed clutch, between the end face gear of the fixed clutch and the connection portion between the fixed clutch and the housing, thereby reducing the thickness of the fixed clutch along the axial direction of the spindle.

2. The tool spindle device for a machine tool according to claim 1, characterized in that the gap is formed by a notch.

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