JP7366777B2 - Spindle device - Google Patents

Description

The present invention relates to a spindle device.

There is a known spindle device in which a drawbar is inserted into a spindle rotatably supported by a housing in a state where the drawbar can move forward and backward in the axial direction and is always biased toward the retreating side by a spring member. (See Reference 1).

In such a spindle device, by moving the drawbar forward against the biasing force of the spring member by the drive means, a collet chuck assembled to the tip of the spindle is released and the tool is unclamped. On the other hand, when the forward pressing force on the drawbar by the driving means is released with the tool inserted into the tip of the spindle, the collet chuck is engaged by the retreating movement of the drawbar by the spring member and the tool is clamped.

Japanese Patent Application Publication No. 2002-86304

In the main shaft device, a small gap is provided between the drawbar and a spring member disposed on the radially outer side of the drawbar. This is because the dimensional accuracy of the inner diameter of the spring member cannot be made very high due to manufacturing reasons, and it is necessary to ensure smooth expansion and contraction of the spring member. Therefore, there is a risk that the spring member may be displaced in the radial direction of the main shaft due to centrifugal force due to rotation of the main shaft or repeated expansion and contraction operations of the spring member when exchanging tools.

On the other hand, in the spindle device described in Patent Document 1, the contact surface between the spring member wound on the drawbar and the support member (collar member) that contacts the spring member in the axial direction has a conical surface shape. It is processed into a tapered shape. This prevents the end portion of the spring member from shifting in the radial direction of the main shaft due to a so-called wedge effect caused by contact between the tapered surface of the collar member and the tapered surface portion of the spring member.

However, in the spindle device described in Patent Document 1, although the axial end portions of the spring member are held by the tapered contact surface, the axial center portion of the spring member is not held and is in a free state. It is. Therefore, for example, due to the centrifugal force caused by the rotation of the main shaft or the expansion/contraction movement of the spring member, the spring member may not be able to maintain a straight state in the axial direction and may be bent at the center. This causes the spring member to partially shift in the radial direction of the main shaft. Therefore, the rotational balance of the main shaft changes, which may cause vibration of the main shaft.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a spindle device that can further suppress the occurrence of vibration.

In order to solve the above problems, a spindle device according to the present invention includes a spindle, a drawbar, a spring member, and a collar member. A tool can be attached to the front end of the main shaft, and a hollow hole is formed in the axial direction. The drawbar is disposed within the hollow hole of the main shaft so as to be movable in the axial direction. The spring member is disposed radially outward of the drawbar and urges the drawbar axially rearward. The collar member is arranged radially outward of the drawbar, contacts an axial end surface of the spring member, and has a cylindrical shape. An end surface of the collar member in the axial direction that contacts the spring member exists on an end plane that is one plane. Further, the end plane is inclined with respect to a plane perpendicular to the central axis of the drawbar.

According to the present invention, it is possible to provide a spindle device that can further suppress the occurrence of vibration.

1 is a side view showing a schematic configuration of a machine tool equipped with a spindle device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of a spindle device. FIG. 3 is a schematic enlarged cross-sectional view of the collar member and the spring member. FIG. 7 is a schematic enlarged sectional view of the vicinity of a collar member and a spring member according to a second embodiment of the present invention.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
Note that, in each figure, common components and components of the same type are denoted by the same reference numerals, and overlapping explanations thereof will be omitted as appropriate. Furthermore, the sizes and shapes of members may be schematically represented in a deformed or exaggerated manner for convenience of explanation.

(First embodiment)
FIG. 1 is a side view showing a schematic configuration of a machine tool 100 equipped with a spindle device 1 according to a first embodiment of the present invention. Hereinafter, for convenience of explanation, the side to which the tool T is attached may be referred to as the "tip" side or "front" side, and the opposite side may be referred to as the "base end" side or "rear" side.

As shown in FIG. 1, in this embodiment, the machine tool 100 is a horizontal machine tool in which the main spindle 2 (see FIG. 2) of the main spindle device 1 is arranged along the horizontal direction. The machine tool 100 includes a base 101, a column 102, a spindle device 1, a workpiece support device 103, and a control panel 104.

A column 102 is provided on the base 101 so as to be movable in the X-axis direction (direction perpendicular to the paper plane of FIG. 1). The column 102 is moved along the X-axis direction by forward and reverse rotation of a screw shaft (not shown) by a motor (not shown) attached to the base 101. The main shaft device 1 is provided so as to be movable in the Y-axis direction (vertical direction) with respect to the column 102. The main spindle device 1 is moved along the Y-axis direction by forward and reverse rotation of a screw shaft (not shown) by a motor (not shown) attached to the column 102.

The workpiece support device 103 supports the workpiece W to be processed. The workpiece support device 103 is provided so as to be movable in the Z-axis direction (back and forth direction) with respect to the base 101. The workpiece support device 103 is moved along the Z-axis direction by forward and reverse rotation of a screw shaft (not shown) by a motor (not shown) attached to the base 101. The workpiece support device 103 also includes a carriage (not shown) that is movable in the Z-axis direction, and a holding section (not shown) that is attached to the carriage and is rotatable around an axis parallel to the X-axis that holds the workpiece W. ).

The machine tool 100 processes a workpiece W using a tool T attached to the tip of a rotating spindle 2 of a spindle device 1 . The control panel 104 centrally controls the operation of each part of the machine tool 100.

FIG. 2 is a sectional view showing the configuration of the spindle device 1. As shown in FIG.
As shown in FIG. 2, the spindle device 1 includes a spindle 2 to which a tool T can be attached at the tip via a tool holder 11. A tool holder 11 to which a tool T is fixed is removably attached to the tip of the main shaft 2.

The main spindle device 1 also includes a cylindrical housing 3 disposed on the radially outer side of the main spindle 2, and a motor 5 for rotating the main spindle 2. The motor 5 includes a rotor 51 fitted around the outer peripheral surface of the main shaft 2 and a stator 52 arranged around the rotor 51 and fixed to the inner peripheral surface of the housing 3.

Further, the main spindle device 1 includes bearings 41 and 42 arranged on the front side and the rear side of the main spindle 2, respectively. Here, the front side is the side of the main spindle 2 on which the tool T is attached. The bearings 41 and 42 rotatably support the main shaft 2 relative to the housing 3. It is preferable that a plurality of bearings 41 (four in this case) be installed in order to obtain reliable static rigidity. As the bearings 41 and 42, rolling bearings such as ball bearings and roller bearings are used here.

A hollow hole 21 is formed inside the main shaft 2 and extends through the main shaft 2 in its axial direction (hereinafter also simply referred to as the "axial direction"). A tapered hole 22 having a complementary shape to the tapered shank portion 12 of the tool holder 11 is formed at the tip of the hollow hole 21 (on the left side in FIG. 2).

The main shaft 2 has a drawbar 6 disposed within the hollow hole 21 of the main shaft 2 so as to be movable in the axial direction. The distal end of the drawbar 6 is configured to be able to engage with a pull stud 13 provided at the proximal end of the tool holder 11 via a steel ball 61. A metal fitting 62 is fixed to the base end of the drawbar 6. A spring member 8 is mounted between the metal fitting 62 and a step portion 23 formed on the inner peripheral surface of the hollow hole 21 of the main shaft 2 via a collar member 7 and a nut member 63.

When the drawbar 6 is moved to the right in FIG. 2 by the elastic force of the spring member 8, the pull stud 13 is pulled in by the steel ball 61, and the shank portion 12 of the tool holder 11 is pressed against the tapered hole 22 of the main shaft 2. be grasped. On the other hand, when the metal fitting 62 is pushed forward against the elastic force of the spring member 8, the hold on the pull stud 13 of the tool holder 11 by the tip of the drawbar 6 and the steel ball 61 is released. Then, the tool T and tool holder 11 are replaced by an automatic tool changer (not shown).

FIG. 3 is a schematic enlarged sectional view of the collar member 7 and the spring member 8.
As shown in FIG. 3, the spring member 8 includes a front spring 81 and a rear spring 82 that are arranged in order from the front side in the axial direction of the main shaft 2 (see FIG. 2, the same applies hereinafter). The collar member 7 includes an intermediate collar 71 disposed between a front spring 81 and a rear spring 82, and a front collar 72 disposed in front of the front spring 81. The main shaft 2, the drawbar 6, and the collar member 7 have a common central axis 93.

That is, from the front side, a front collar 72, a front spring 81, an intermediate collar 71, a rear spring 82, and a nut member 63 are inserted into the drawbar 6 in this order in the axial direction in contact with each other. The front collar 72 and the intermediate collar 71 are fitted onto the outer peripheral surface of the drawbar 6 so as to be slidable in the axial direction. The front spring 81 and the rear spring 82 are installed on the outer peripheral surface of the drawbar 6 so as to be slidable in the axial direction with a small gap. The nut member 63 is screwed onto the rear end of the drawbar 6. By screwing and fixing the nut member 63 to the drawbar 6, the spring member 8 (front spring 81 and rear spring 82) is compressed.

As the spring member 8, a so-called helical disc spring is used. A helical disc spring is composed of two independent disc-shaped coil springs arranged in a double spiral. Here, the front spring 81 is a right-handed helical disc spring, and the rear spring 82 is a left-handed helical disc spring, but they may be reversed. That is, the front spring 81 and the rear spring 82 are a pair of symmetrical helical disc springs with opposite winding directions. This is because when a helical disc spring is compressed, it tends to twist in the direction of releasing the spiral, so this twist is canceled out. In this case, the intermediate collar 71 arranged between the front spring 81 and the rear spring 82 rotates on the drawbar 6 to absorb the twist.

The front end surface 73 of the intermediate collar 71 that contacts the front spring 81 lies on one plane, a first end plane 91 . Further, the rear end surface 74 of the intermediate collar 71 that contacts the rear spring 82 exists on a second end plane 92 that is one plane.

The first end plane 91 and the second end plane 92 are collectively referred to as the end plane 9. The end planes 9 (first end plane 91 and second end plane 92) are inclined with respect to a plane 94 perpendicular to the central axis 93 of the drawbar 6. The first end plane 91 and the second end plane 92 are set parallel to each other. The inclination angle θ of the end plane 9 (the first end plane 91 and the second end plane 92) with respect to the plane 94 is set to an appropriate value (for example, 1 to 20 degrees).

A front end surface 75 and a rear end surface 76 of the front collar 72 are both set perpendicular to the central axis 93 of the drawbar 6.

Next, the operation of the machine tool 100 equipped with the spindle device 1 will be explained.
When exchanging tools, the metal fitting 62 shown in FIG. 2 is pushed forward against the elastic force of the spring member 8. This releases the pull stud 13 of the tool holder 11 from being held by the tip of the drawbar 6 and the steel ball 61. In this state, the tool T and tool holder 11 are replaced by an automatic tool changer (not shown). After the new tool T and tool holder 11 are set at the tip of the spindle 2, when the forward push against the metal fitting 62 is released, the drawbar 6 is moved to the right in FIG. 2 by the elastic force of the spring member 8. Ru. As a result, the pull stud 13 is pulled in by the steel ball 61, and the shank portion 12 of the tool holder 11 is pressed into contact with the tapered hole 22 of the main shaft 2 and is gripped. In this way, the tool T is attached to the tip of the spindle 2 via the tool holder 11. Subsequently, when a start of operation is instructed through an operation section (not shown), the motor 5 is driven and the main shaft 2 is rotated. Then, as shown in FIG. 1, the workpiece W is processed by relative movement of the workpiece W and the tool T.

As shown in FIG. 2, the spindle device 1 according to the present embodiment described above includes a spindle 2, a drawbar 6, a spring member 8, and a collar member 7 (intermediate collar 71). A tool T can be attached to the main shaft 2 at the front end thereof, and a hollow hole 21 is formed in the axial direction. The drawbar 6 is disposed within the hollow hole 21 of the main shaft 2 so as to be movable in the axial direction. The spring member 8 is disposed on the radially outer side of the drawbar 6 and biases the drawbar 6 toward the rear side in the axial direction. The intermediate collar 71 is arranged on the radially outer side of the drawbar 6, contacts the end surface of the spring member 8 in the axial direction, and has a cylindrical shape. As shown in FIG. 3, the end surface of the intermediate collar 71 in the axial direction that contacts the spring member 8 exists on the end plane 9, which is one plane. Further, the end plane 9 is inclined with respect to a plane 94 perpendicular to the central axis 93 of the drawbar 6.

In this embodiment, the axial end surface of the intermediate collar 71 that contacts the spring member 8 lies on the end plane 9 which is a plane inclined with respect to a plane 94 perpendicular to the central axis 93 of the drawbar 6. exists in In other words, the axial end surface of the intermediate collar 71 that contacts the spring member 8 forms a plane that is inclined with respect to a plane 94 perpendicular to the central axis 93 of the drawbar 6 .

When the end surface of the spring member 8 comes into contact with the inclined end surface of the intermediate collar 71 and receives a pressing force, the spring member 8 moves in a direction in which the end surface of the spring member 8 is brought into close contact with the inclined end surface of the intermediate collar 71 as a whole. A bending force is generated that deforms the In addition, since the reaction force from the intermediate collar 71 acting on the spring member 8 includes a component of force in the radial direction according to the inclination angle θ of the end surface of the intermediate collar 71, the reaction force in the radial direction of the main shaft 2 A pressing force that moves the spring member 8 is generated. In this way, the spring member 8 is bent in a certain direction and/or pressed in a certain radial direction, so that it is kept in a certain set state intentionally shifted from its normal position. Therefore, the spring member 8 is prevented from further shifting in the radial direction of the main shaft 2 from the once set state due to centrifugal force due to rotation of the main shaft 2 or expansion/contraction movement of the spring member 8 during tool exchange. This prevents the rotational balance of the main shaft 2 from changing and causing vibration of the main shaft 2. In general, after the spring member 8 is set, the balance of the main shaft 2 is adjusted by, for example, attaching a weight to the main shaft 2.
Therefore, according to the present embodiment, it is possible to provide the spindle device 1 that can further suppress the occurrence of vibration.

Further, in this embodiment, the spring member 8 includes a front spring 81 and a rear spring 82 that are arranged in order from the front side in the axial direction of the main shaft 2. The collar member 7 has an intermediate collar 71 arranged between a front spring 81 and a rear spring 82. The front end surface 73 of the intermediate collar 71 that contacts the front spring 81 lies on one plane, a first end plane 91 . The rear end surface 74 of the intermediate collar 71 that contacts the rear spring 82 lies on a second end plane 92 which is one plane. The first end plane 91 and the second end plane 92 are set parallel to each other.

In this configuration, the bending direction of the front spring 81 and the direction of the pressing force that moves the front spring 81 in the radial direction are the same as the bending direction of the rear spring 82 and the direction of the pressing force that moves the rear spring 82 in the radial direction. , respectively, are reversed. Therefore, in a deliberately shifted and constant set state, the displacement of the front spring 81 and the displacement of the rear spring 82 occur in a direction that offsets the rotational balance. Thereby, balance adjustment of the main shaft 2, which is performed by attaching a weight to the main shaft 2, for example, can be easily performed because only a small amount of adjustment is required.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a schematic enlarged sectional view of the collar member 7a and the vicinity of the spring member 8 according to the second embodiment of the present invention.
Hereinafter, regarding the second embodiment of the present invention, differences from the above-described first embodiment will be mainly explained, and common components or similar components will be given the same reference numerals and explanations will be omitted as appropriate. do.

In the second embodiment, the front end surface 73a of the intermediate collar 71a that contacts the front spring 81 exists on a first end plane 91a, which is one plane. A rear end surface 74a of the intermediate collar 71a that contacts the rear spring 82 exists on a second end plane 92a that is one plane. The first end plane 91a and the second end plane 92a are inclined in opposite directions to a plane 94 perpendicular to the central axis 93 of the drawbar 6 by an inclination angle θ. That is, the first end plane 91a and the second end plane 92a are set to be symmetrical with respect to a plane 94 that passes through the axial center 77 of the intermediate collar 71a and is perpendicular to the central axis 93 of the drawbar 6. has been done.

In this configuration, the bending direction of the front spring 81 and the direction of the pressing force that moves the front spring 81 in the radial direction are the same as the bending direction of the rear spring 82 and the direction of the pressing force that moves the rear spring 82 in the radial direction. , each will be the same. Also in this case, further displacement of the spring member 8 in the radial direction of the main shaft 2 from the once set state is suppressed.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the configuration described in the embodiments. The present invention can be modified as appropriate without departing from the spirit thereof, including appropriately combining or selecting the configurations described in the embodiments. Furthermore, some of the configurations of the embodiments can be added, deleted, or replaced.

For example, in the embodiment described above, the spring member 8 has the front spring 81 and the rear spring 82, but it may be configured with one spring and the intermediate collars 71 and 71a may be omitted.
In this case, the rear end surface of the front collar 72 that contacts the front end surface of the spring member 8 exists on one end plane, which is perpendicular to the central axis 93 of the drawbar 6. It is preferable to be configured to be inclined with respect to a plane.
Alternatively, a rear collar is arranged on the rear side of the spring member 8, and the front end face of the rear collar is on one end plane, and the end plane is perpendicular to the central axis 93 of the drawbar 6. It may also be configured to be inclined with respect to a normal plane. Alternatively, instead of arranging the rear collar, the front end surface of the nut member 63 exists on one end plane, and the end plane is a plane 94 perpendicular to the central axis 93 of the drawbar 6. It may also be configured to be inclined with respect to. In this case, the nut member 63 also functions as the collar member of the present invention.

Further, the front collar 72 arranged on the front side of the front spring 81 may be omitted. In this case, the front end surface of the front spring 81 comes into direct contact with the step 23 formed on the inner peripheral surface of the hollow hole 21 of the main shaft 2.

Further, in the above-described embodiment, a case has been described in which the spindle device 1 is mounted on the horizontal machine tool 100, but the present invention is not limited to this. The spindle device 1 can be mounted on various machine tools such as vertical machine tools. That is, in the state of use, the installation direction of the spindle device 1 may be different from the direction shown in FIG. 1 .

1 Main shaft device 2 Main shaft 21 Hollow hole 6 Drawbar 7, 7a Collar member 71, 71a Intermediate collar 72 Front collar 73, 73a Front end surface 74, 74a Rear end surface 77 Axial center 8 Spring member 81 Front spring 82 Rear spring 9 End plane 91, 91a First end plane 92, 92a Second end plane 93 Central axis 94 Plane T Tool

Claims (3)

A main shaft with a hollow hole formed in the axial direction and a tool can be attached to the front end.
a drawbar disposed in the hollow hole of the main shaft so as to be movable in the axial direction;
a spring member disposed radially outside the drawbar and biasing the drawbar axially rearward;
a cylindrical collar member disposed on the radially outer side of the drawbar and in contact with an axial end surface of the spring member;
An axial end surface of the collar member that contacts the spring member is on an end plane that is one plane,
The spindle device, wherein the end plane is inclined with respect to a plane perpendicular to the central axis of the drawbar. The spring member has a front spring and a rear spring arranged in order from the front side in the axial direction of the main shaft,
the collar member has an intermediate collar disposed between the front spring and the rear spring;
The front end surface of the intermediate collar that contacts the front spring lies on a first end plane that is one plane,
The rear end surface of the intermediate collar that contacts the rear spring is on a second end plane that is one plane,
The spindle device according to claim 1, wherein the first end plane and the second end plane are set parallel to each other. The spring member has a front spring and a rear spring arranged in order from the front side in the axial direction of the main shaft,
the collar member has an intermediate collar disposed between the front spring and the rear spring;
The front end surface of the intermediate collar that contacts the front spring lies on a first end plane that is one plane,
The rear end surface of the intermediate collar that contacts the rear spring is on a second end plane that is one plane,
The first end plane and the second end plane are set in plane symmetry with respect to a plane passing through the axial center of the intermediate collar and perpendicular to the central axis of the drawbar. The spindle device according to claim 1.

Images