Billet rotation / holding device and billet holding unit

Abstract

A billet rotation / holding device S comprises a motor M, a pressurizer P, and a billet holding unit U. The billet holding unit is provided with a motor-side holder and a pressurizer-side holder. The billet holding unit uses pressure that is output from a pressurizer shaft to a first side in the axial direction to sandwich end faces of the billet on both sides in the axial direction with the motor-side holder and the pressurizer-side holder. The motor-side holder and the pressurizer-side holder are each provided with a fixed part, a moving part, and a body elastic part.

Description

Billet rotation and holding device, and billet holding unit

[0001] This application claims priority from Japanese Patent Application No. 2024-050094, filed on March 26, 2024, the entire contents of which are incorporated herein by reference. This invention relates to a billet rotating and holding device and a billet holding unit.

[0002] Conventionally, there has been a device for holding and rotating a billet (a cylindrical workpiece) that holds the outer surface of the billet with multiple jaws (chucks) arranged on the outer periphery of the billet (for example, Patent Document 1).

[0003] Japanese Publication No. 57-96731

[0004] However, when using the above-described conventional device, it is necessary to secure space on the outer periphery of the billet for the multiple claws that hold the billet. In cases where it is difficult to secure space on the outer periphery of the billet, such a device may not be suitable. Another method for holding and rotating a billet involves holding both ends of the billet. However, since high precision is not generally required for the shape of the billet, the end faces (cut surfaces) of the billet are generally not perfectly perpendicular to the central axis of the billet, but are generally inclined non-perpendicularly to the central axis of the billet. Even in such cases, it has been difficult to rotate the billet while firmly holding both ends of the billet.

[0005] The present invention is intended to solve the above-mentioned problems, and aims to provide a billet rotating and holding device and a billet holding unit that can firmly hold both ends of a billet and rotate it, even if the end faces of the billet are inclined.

[0006] [1] A billet rotating and holding device configured to rotate a billet while holding it, comprising: an electric motor having an electric motor shaft; a pressurizer having a pressurizer shaft arranged to face the electric motor shaft in the axial direction; and a billet holding unit, wherein the billet holding unit comprises: an electric motor side holding tool attached to the electric motor shaft and configured to hold an end face of the billet on a first axial side; and a pressurizer side holding tool attached to the pressurizer shaft and configured to hold an end face of the billet on a second axial side; the pressurizer is configured to output a pressure force toward the first axial side via the pressurizer shaft; and the billet holding unit is configured to clamp both end faces of the billet in the axial direction by the electric motor side holding tool and the pressurizer side holding tool using the pressure force toward the first axial side output from the pressurizer shaft; and the electric motor side holding tool and the pressurizer side holding tool each comprise: A billet rotation and holding device comprising: a fixed part configured to be fixed to the electric motor shaft or the pressurizing machine shaft and having an internal space that is open at least on the axial billet side; a floating part configured to be able to move freely in the axial direction within the internal space of the fixed part, configured to be able to transmit rotational torque between the fixed part and the floating part, and having a holding surface on the axial billet side configured to hold the end face of the billet on the first axial side or the second axial side; and a main body elastic part consisting of one or more disc springs arranged approximately coaxially with the fixed part between the fixed part and the floating part within the internal space of the fixed part.

[0007] [2] The electric motor side holding tool and the pressurizer side holding tool each have an outer peripheral surface of the floating part, each configured to be convex or concave in the radial direction, and a plurality of engaging portions arranged along the circumferential direction; and the fixed part has an inner peripheral surface that partitions the internal space, each configured to be concave or convex in the radial direction, and a plurality of engaged portions that are arranged along the circumferential direction and engage with the plurality of engaging portions; and the engagement between the plurality of engaging portions and the plurality of engaged portions makes it possible to transmit rotational torque between the fixed part and the floating part, as described in [1].

[0008] [3] A billet rotation holding device described in [1] or [2], wherein the holding surfaces of the electric motor side holding tool each have concave and convex strips extending approximately radially and arranged alternately along the circumferential direction.

[0009] [4] A billet rotation and holding device as described in [3], wherein the protruding tip edge of each of the convex strips on the axial billet side extends radially inward toward the axial opposite side of the billet.

[0010] [5] A billet rotating and holding device as described in [3] or [4], wherein the motor side holding tool has an extrusion portion configured to protrude beyond the holding surface toward the second axial direction and extrude the billet toward the second axial direction when the force applied from the billet to the holding surface toward the first axial direction becomes less than a predetermined value.

[0011] [6] A billet rotating and holding device according to any one of [1] to [5], further comprising a magnetic field generating device configured to generate a magnetic field in a specified working space, wherein the billet rotating and holding device is configured to rotate the billet while holding the billet so that the billet is positioned within the specified working space, generate a magnetic field in the specified working space using the magnetic field generating device, and heat the billet by an induced current flowing within the billet during this time.

[0012] [7] A billet holding unit configured to be used in the billet rotating and holding device described in any one of [1] to [6].

[0013] According to the present invention, a billet rotating and holding device and a billet holding unit can be provided that can rotate a billet while firmly holding both ends of the billet, even if the end faces of the billet are inclined.

[0014] 1 is a perspective view schematically showing a billet rotating and holding device according to an embodiment of the present invention, which is equipped with a billet holding unit according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing the motor-side holding tool of FIG. 1. FIG. 3 is an axial cross-sectional view schematically showing the motor-side holding tool of FIG. 2 when no force from the billet is applied to the holding surface (natural state), taken along the central axis of the motor-side holding tool. FIG. 4 is an explanatory view for explaining the operation of the motor-side holding tool of FIG. 2 when force from the billet is applied to the holding surface. FIG. 5 is a cross-sectional view generally perpendicular to the axis of the motor-side holding tool of FIG. 3, taken along line A-A of FIG. 3. FIG. 6 is a perspective view schematically showing the pressurizer-side holding tool of FIG. 1. FIG. 7 is an axial cross-sectional view generally perpendicular to the axis of the pressurizer-side holding tool of FIG. 7 when no force from the billet is applied to the holding surface (natural state), taken along the central axis of the pressurizer-side holding tool. 10 is an explanatory diagram for explaining the effects of the billet rotating and holding device and the billet holding unit according to the embodiment of FIG. 1 to FIG. 8. FIG. 11 is an explanatory diagram for explaining the effects of the billet rotating and holding device and the billet holding unit according to a modified example of the present invention.

[0015] The billet rotating and holding device and billet holding unit according to the present invention can be used for any purpose, for example, as a billet heating device for heating a billet (e.g., an aluminum billet). Hereinafter, an exemplary embodiment of the billet rotating and holding device and billet holding unit according to the present invention will be described with reference to the drawings.

[0016] FIG. 1 is a diagram schematically illustrating a billet rotating and holding device S according to one embodiment of the present invention. The billet rotating and holding device S is configured to rotate a billet (columnar workpiece) B while holding the billet B. FIG. 1 shows the billet rotating and holding device S holding the billet B. The billet B is preferably made of metal, for example, aluminum. In the example of FIG. 1, the billet B has a substantially cylindrical shape, but may have another columnar shape.

[0017] 1, the billet rotating and holding device S includes an electric motor M, a pressurizer P, and a billet holding unit U according to one embodiment of the present invention. The billet holding unit U includes an electric motor-side holder HM and a pressurizer-side holder HP (in this example, the billet holding unit U is composed of the electric motor-side holder HM and the pressurizer-side holder HP). The billet holding unit U according to this embodiment is configured to be used in the billet rotating and holding device S according to any embodiment of the present invention. As will be described later, the billet rotating and holding device S is configured to rotate the billet B while clamping both end faces Bf of the billet B via the billet holding unit U between the electric motor shaft MS of the electric motor M and the pressurizer shaft PS of the pressurizer P.

[0018] The electric motor M has an electric motor shaft MS. The electric motor shaft MS is a drive shaft (output shaft) that outputs rotational torque. The electric motor M may have any configuration, for example, the configuration of any known electric motor.

[0019] As shown with arrows in Figure 1 and elsewhere, for convenience of explanation, in this specification, the direction parallel to the central axis MSO of the electric motor shaft MS when the billet rotating and holding device S is holding a billet B (Figure 1) will be referred to as the "axial direction AD." One side in the axial direction AD will be referred to as the "first axial side AD1," and the other side in the axial direction AD will be referred to as the "second axial side AD2." The side closer to the billet B in the axial direction AD will be referred to as the "axial billet side ADB," and the side farther from the billet B in the axial direction AD will be referred to as the "anti-axial billet side ADA." The direction perpendicular to the axial direction AD will be referred to as the "axial direction." In this specification, the circumferential direction centered on the central axis MSO of the electric motor shaft MS (or an extension thereof) will sometimes be simply referred to as the "circumferential direction." Additionally, unless otherwise specified, the terms "outer peripheral side" and "inner peripheral side" refer to the outer peripheral side and the inner peripheral side, respectively, when the center is the central axis MSO (or an extension thereof) of the motor shaft MS. Furthermore, in this specification, a direction perpendicular to the axial direction AD is referred to as the "longitudinal direction VD," and a direction perpendicular to each of the axial direction AD and the longitudinal direction VD is referred to as the "depth direction DD." Furthermore, one side of the longitudinal direction VD is referred to as the "longitudinal first side VD1," and the other side of the longitudinal direction VD is referred to as the "longitudinal second side VD2." In this embodiment, the longitudinal direction VD is oriented vertically, and the longitudinal first side VD1 is oriented upward. Consequently, the axial direction AD and the depth direction DD are each parallel to the horizontal direction, but the longitudinal first side VD1 (and each of the other directions) may be oriented in any direction.

[0020] As shown in FIG. 1 , the pressurizer P has a pressurizer shaft PS. The pressurizer shaft PS is disposed opposite the electric motor shaft MS in the axial direction AD. The ends of the electric motor shaft MS and the pressurizer shaft PS are spaced apart and opposite each other in the axial direction AD. The electric motor shaft MS and the pressurizer shaft PS are preferably disposed such that their respective central axes MSO and HPO are aligned substantially in the same straight line. The electric motor M and the pressurizer P may be mounted on support bases TA and TC, respectively, so that their respective heights and positions can be adjusted. The pressurizer P is configured to output a pressurizing force toward a first axial side AD1 via the pressurizer shaft PS. The pressurizer shaft PS is configured to be displaceable in the axial direction AD and is configured to output a pressurizing force toward the first axial side AD1 while displacing toward the first axial side AD1. The pressurizer shaft PS is configured as a driven shaft. That is, when the billet rotating and holding device S holds the billet B ( FIG. 1 ), the pressurizer P is configured such that the pressurizer shaft PS is rotated together with the billet holding unit U and the billet B by the rotational torque output from the electric motor shaft MS while outputting the pressurizing force. The specific configuration of the pressurizer P may be arbitrary. For example, the pressurizer P may be configured to output the pressurizing force by displacing the pressurizer shaft PS in the axial direction AD by having an electric or hydraulic configuration. The pressurizer P may be automatically controlled by a processing device (CPU, circuit device, etc.) that performs various processes according to a predetermined program stored in an arbitrary storage device (ROM, RAM, etc.), or may operate in response to human operation. By outputting the pressurizing force from the pressurizer shaft PS toward the first axial side AD1, the billet B is more firmly clamped between the electric motor shaft MS and the pressurizer shaft PS via the billet holding unit U, thereby preventing the billet B from coming off or shifting from the billet rotating and holding device S.

[0021] The billet holding unit U comprises a motor-side holding fixture HM and a pressurizer-side holding fixture HP ( FIG. 1 ). The motor-side holding fixture HM (also simply referred to as “holding fixture HM”) is configured to be attached to the motor shaft MS. When attached to the motor shaft MS, the motor-side holding fixture HM is configured to hold the end face Bf of the billet B on the first axial side AD1. The pressurizer-side holding fixture HP (also simply referred to as “holding fixture HP”) is configured to be attached to the pressurizer shaft PS. When attached to the pressurizer shaft PS, the pressurizer-side holding fixture HP is configured to hold the end face Bf of the billet B on the second axial side AD2. When the motor-side holding fixture HM is attached to the motor shaft MS and the pressurizer-side holding fixture HP is attached to the pressurizer shaft PS, the motor-side holding fixture HM and the pressurizer-side holding fixture HP face each other in the axial direction AD ( FIG. 1 ). The billet holding unit U is configured to clamp the end faces Bf of the billet B on both sides in the axial direction AD using the motor side holding tool HM and the pressurizing machine side holding tool HP, using the pressure force toward the first axial side AD1 output from the pressurizing machine shaft PS.

[0022] In the embodiment of FIG. 1 , the billet rotating and holding device S is configured as a billet heating device configured to heat the billet B. The billet rotating and holding device S further includes a magnetic field generator J. The magnetic field generator J is configured to generate a magnetic field in a predetermined working space J6. In this embodiment, the billet rotating and holding device S is configured to rotate (spin) the billet B while holding the billet B so that it is positioned within the predetermined working space J6 using an electric motor M, a press P, and a billet holding unit U, and to generate a magnetic field in the predetermined working space J6 using the magnetic field generator J, thereby heating the billet B by an induced current flowing in the billet B. The billet B heated by the billet rotating and holding device S is then transported to a processing machine such as an extruder, where it is subjected to processing such as extrusion. The magnetic field generator J may be installed on a support table TB, for example, and its height and position may be adjusted. The magnetic field generator J may have any configuration. The magnetic field generating device J may include, for example, an iron core J2, a superconducting coil (not shown), a vacuum insulating container J4, etc. In this case, the superconducting coil (not shown) is housed inside the vacuum insulating container J4. As illustrated in FIG. 1 , the vacuum insulating container J4 may be disposed on both sides of the predetermined working space J6 (and thus the billet B) in the depth direction DD. Also, a portion of the iron core J2 may be housed inside the vacuum insulating container J4. However, the billet rotating and holding device S may be used for purposes other than heating the billet B. The billet rotating and holding device S does not have to include the magnetic field generating device J.

[0023] The motor-side holder HM and the pressurizer-side holder HP will be described in more detail below. FIGS. 2 to 5 show an example of the motor-side holder HM. FIG. 2 is a perspective view schematically showing an example of the motor-side holder HM. FIG. 3 is an axial cross-sectional view, taken along the central axis HMO of the motor-side holder HM, of the motor-side holder HM of FIG. 2 when no force from the billet B is applied to the holding surface HS of the motor-side holder HM (natural state). FIG. 4 is an explanatory diagram for explaining the operation of the motor-side holder HM of FIG. 2 when force from the billet B is applied to the holding surface HS of the motor-side holder HM. FIG. 5 is an axial cross-sectional view, taken along line A-A in FIG. 3, which is parallel to the axial direction, of the motor-side holder HM of FIG. 3. FIGS. 6 to 8 show an example of the pressurizer-side holder HP. Fig. 6 is a perspective view schematically showing an example of a pressurizer-side holder HP. Fig. 7 is an axial cross-sectional view schematically showing the pressurizer-side holder HP of Fig. 6 when the holding surface HS of the pressurizer-side holder HP is in a state (natural state) where no force from the billet B is applied to the holding surface HS of the pressurizer-side holder HP, taken along the central axis HPO of the pressurizer-side holder HP. Fig. 8 is an axial cross-sectional view schematically showing the pressurizer-side holder HP of Fig. 7, taken along line B-B in Fig. 7, which is parallel to the axial direction. As shown in Figs. 2 to 8, the holders HM and HP each include a fixed portion HO, a floating portion HY, and a main body elastic portion HE.

[0024] The fixing portion HO of the motor-side holder HM is configured to be fixed to the motor shaft MS (FIG. 3). As a result, the fixing portion HO of the motor-side holder HM is configured to be integral with the motor shaft MS and move in conjunction with the motor shaft MS. When fixed to the motor shaft MS, the fixing portion HO of the motor-side holder HM is coaxial with the motor shaft MS. The fixing portion HO of the pressurizer-side holder HP is configured to be fixed to the pressurizer shaft PS (FIG. 7). As a result, the fixing portion HO of the pressurizer-side holder HP is configured to be integral with the pressurizer shaft PS and move in conjunction with the pressurizer shaft PS. When fixed to the pressurizer shaft PS, the fixing portion HO of the pressurizer-side holder HP is coaxial with the pressurizer shaft PS. Fixation between the fixing portion HO and the motor shaft MS or the pressurizer shaft PS may be performed by any method and form, such as engagement, fastening, or welding. In each of the holders HM and HP, the fixed portion HO may be formed by connecting multiple separate members by fastening or the like, or may be formed of only a single member. It is preferable that the fixed portion HO is formed to contain metal. The fixed portion HO may be formed of a single material, or may be formed of multiple types of materials. In each of the holders HM and HP, the fixed portion HO has an internal space HOh that is open at least on the axial billet ADB side ( FIGS. 3 and 7 ). The internal space HOh of the fixed portion HO may be formed as a through-hole penetrating the fixed portion HO in the axial direction AD by also being open on the axial opposite billet ADA side, or may be formed as a recess that is closed on the axial opposite billet ADA side and is open only on the axial billet ADB side.

[0025] In each of the holders HM and HP, the floating portion HY is configured to be floating (movable) in the axial direction AD within the internal space HOh of the fixed portion HO ( FIGS. 3 and 7 ). The floating portion HY is arranged so as to be substantially coaxial with the fixed portion HO when no force is applied to the holding surface HS of the holders HM and HP from the billet B or the like (natural state) ( FIG. 3 ). More specifically, in this embodiment, as illustrated in FIGS. 3 and 7 , the outer peripheral surface of the floating portion HY has a plurality of engaging portions HYE configured in a radially convex shape (i.e., having a shape that protrudes outward). The engaging portion HYE has a surface HYsc facing the billet side ADB in the axial direction, a surface HYsb facing the anti-billet side ADA in the axial direction and located further on the anti-billet side ADA than surface HYsc, and a surface HYsd facing the outer periphery and connecting the outer periphery ends of surface HYsc and surface HYsb. In addition, the inner circumferential surface of the fixing portion HO that defines the internal space HOh has a plurality of engaged portions HOE that are concave in the radial direction (i.e., have a shape recessed toward the outer periphery). The engaged portion HOE has a surface HOsc facing the axially opposite billet side ADA, a surface HOsb facing the axially opposite billet side ADB and located further on the axially opposite billet side ADA than surface HOsc, and a surface HOsd facing inward and connecting the outer peripheral ends of surfaces HOsc and HOsb. The engaging portion HYE of the floating portion HY and the engaged portion HOE of the fixed portion HO are engaged with each other (FIGS. 3 and 7). The length in the axial direction AD of the engaging portion HYE or the engaged portion HOE that is configured concave (in this example, the engaged portion HOE) is longer than the length in the axial direction AD of the engaging portion HYE or the engaged portion HOE that is configured convex (in this example, the engaging portion HYE). That is, the distance in the axial direction AD between the surfaces HOsc and HOsb of the engaged portion HOE is longer than the distance in the axial direction AD between the surfaces HYsc and HYsb of the engaging portion HYE. Therefore, a gap exists in the axial direction AD between the engaging portion HYE and the engaged portion HOE, and as a result, the one of the engaging portion HYE and the engaged portion HOE that is configured as a convex shape (in this example, the engaging portion HYE) is able to move in the axial direction AD inside the one of the engaging portion HYE and the engaged portion HOE that is configured as a concave shape (in this example, the engaged portion HOE).In this example, the engaging portion HYE is movable in the axial direction AD between the surfaces HOsc and HOsb of the engaged portion HOE. That is, the floating portion HY is movable in the axial direction AD relative to the fixed portion HO by the difference in length between the engaging portion HYE and the engaged portion HOE in the axial direction AD. However, this is not limited to the configuration of this example. For example, the engaging portion HYE of the floating portion HY may be configured to be concave in the radial direction (i.e., have a shape recessed toward the inner periphery), and the engaged portion HOE of the fixed portion HO may be configured to be convex in the radial direction (i.e., have a shape protruding toward the inner periphery). Note that when the engaging portion HYE or the engaged portion HOE is described in this specification, unless otherwise specified, it is assumed that the description refers to each engaging portion HYE or each engaged portion HOE.

[0026] In this embodiment, in each of the holders HM and HP, the floating portion HY is configured to be able to transmit rotational torque between itself and the fixed portion HO ( FIGS. 5 and 8 ). This allows the floating portion HY to move freely in the axial direction AD relative to the fixed portion HO while rotating in conjunction with the fixed portion HO. More specifically, in this embodiment, as illustrated in FIGS. 5 and 8 , the outer peripheral surface of the floating portion HY has the above-mentioned multiple engaging portions HYE, which are arranged at intervals from one another along the circumferential direction. Furthermore, the inner peripheral surface of the fixed portion HO, which defines the internal space HOh, has the above-mentioned multiple engaged portions HOE, which are arranged at intervals from one another along the circumferential direction and engage with the multiple engaging portions HYE of the floating portion HY. In this way, the engagement between the multiple engaging portions HYE and the multiple engaged portions HOE enables transmission of rotational torque between the fixed portion HO and the floating portion HY. Thus, in this embodiment, the engagement relationship between the engaging portion HYE of the floating portion HY and the engaged portion HOE of the fixed portion HO allows the floating portion HY to move freely in the axial direction AD relative to the fixed portion HO, while also allowing rotational torque to be transmitted between the fixed portion HO and the floating portion HY.

[0027] In each of the holders HM and HP, the floating portion HY has a holding surface HS configured to hold the end face Bf of the billet B on the axial billet side ADB of the floating portion HY (FIGS. 3 and 7). The holding surface HS is configured from at least a portion of the end face of the axial billet side ADB of the floating portion HY. The holding surface HS of the motor-side holder HM is configured to hold the end face Bf of the billet B on the axial first side AD1 (FIG. 1). The holding surface HS of the pressurizer-side holder HP is configured to hold the end face Bf of the billet B on the axial second side AD2 (FIG. 1). In each of the holders HM and HP, the floating portion HY may be configured by connecting multiple separate members by fastening or the like, or may be configured from only a single member. It is preferable that the floating portion HY be configured to include a metal. The floating portion HY may be made of a single material or may be made of multiple types of materials. For example, the floating portion HY may be made of a heat insulating material in addition to a metal or the like. In this embodiment, in each of the holders HM and HP, a portion of the floating portion HY extends toward the axial billet side ADB beyond the end face of the axial billet side ADB of the fixed portion HO, and therefore the holding surface HS is located closer to the axial billet side ADB than the end face of the axial billet side ADB of the fixed portion HO ( FIGS. 3 and 7 ).

[0028] In each of the holders HM and HP, the main body elastic portion HE is disposed between the fixed portion HO and the floating portion HY within the internal space HOh of the fixed portion HO (FIGS. 3 and 7). This allows the main body elastic portion HE to apply elastic force between the fixed portion HO and the floating portion HY. The main body elastic portion HE is disposed approximately coaxially with the fixed portion HO (and thus also approximately coaxially with the floating portion HY). The main body elastic portion HE is composed of one or more disc springs HD. The one or more disc springs HD constituting the main body elastic portion HE are disposed approximately coaxially with the fixed portion HO (and therefore also approximately coaxially with the floating portion HY). It is preferable that the main body elastic portion HE has multiple disc springs HD. In this case, the multiple disc springs HD constituting the main body elastic portion HE are arranged along the axial direction AD. The arrangement of the plurality of disc springs HD along the axial direction AD may be any arrangement, such as only parallel, only series, or a combination of parallel and series.

[0029] In this embodiment, the motor-side holder HM (FIG. 3) has a main body elastic portion HE disposed in the space within the internal space HOh of the fixed portion HO, between a surface HYsa on the outer peripheral surface of the floating portion HY that faces the axially opposite side ADA of the billet, and a surface HOsa on the inner peripheral surface of the fixed portion HO that defines the internal space HOh and faces the axially opposite side ADA of the billet, and is located closer to the axially opposite side ADA than surface HYsa. When the holder HM is in its natural state (FIG. 3), the main body elastic portion HE is in contact with these surfaces HYsa and HOsa, and thus elastically connects these surfaces HYsa and HOsa together (and thus the floating portion HY and the fixed portion HO together). In the holder HM, the main body elastic part HE may be compressed in the axial direction AD when the holder HM is in its natural state (Figure 3), and thus the floating part HY may be biased toward the axial billet side ADB by the main body elastic part HE.

[0030] In this embodiment, the pressurizer-side holder HP (FIG. 7) has a main body elastic portion HE composed of two partial elastic portions HEA and HEB. Each of the partial elastic portions HEA and HEB is composed of one or more disc springs HD. Between the two partial elastic portions HEA and HEB in the axial direction AD, an additional floating portion HN is arranged, which is configured to be able to float in the axial direction AD within the internal space HOh of the fixed portion HO. The additional floating portion HN is located on the opposite side ADA of the billet in the axial direction relative to the floating portion HY (also referred to as the "main body floating portion HY"). The fixed portion HO has, at an axially opposite side ADA of the billet than the floating portion HY, a substantially cylindrical outer tube portion HOH having an outer peripheral surface of the fixed portion HO, and an inner peripheral portion HOL located more inward than the outer tube portion HOH, and an annular internal space HOh is formed between the outer tube portion HOH and the inner peripheral portion HOL. The outer tube portion HOH extends toward the axial billet side ADB beyond the end face of the inner peripheral portion HOL on the axial billet side ADB. One partial elastic portion HEA of the main body elastic portion HE is disposed in the internal space HOh of the fixed portion HO, on the axial billet side ADB of the inner peripheral portion HOL of the fixed portion HO, between a surface HYsa on the outer peripheral surface of the floating portion HY facing the axial opposite side ADA of the billet, and a surface HNa on the additional floating portion HN facing the axial billet side ADB and located closer to the axial opposite side ADA of the billet than surface HYsa. Surface HYsa is located closer to the axial opposite side ADA of the billet than surface HYsa of the engaging portion HYE. When the holder HP is in its natural state ( FIG. 7 ), the partial elastic portion HEA is in contact with these surfaces HYsa and HNa, and thus elastically connects these surfaces HYsa and HNa (and thus the floating portion HY and the additional floating portion HN). The other partial elastic portion HEB of the main elastic portion HE is arranged in the space within the internal space HOh of the fixed portion HO, on the outer peripheral side of the inner peripheral portion HOL of the fixed portion HO, between the surface HNc of the axial opposite billet side ADA of the additional floating portion HN and the surface HOf on the outer peripheral surface of the inner peripheral portion HOL of the fixed portion HO, which faces the axial billet side ADB and is located closer to the axial opposite billet side ADA than the surface HNc.The partially elastic member HEB is in contact with these faces HNc and HOf when the holder HP is in its natural state (FIG. 7), and thus elastically connects these faces HNc and HOf (and thus the additional floating member HN and the fixed member HO). The additional floating member HN has a face HOe facing the axial billet side ADB between the faces HNa and HNc in the axial direction AD. Displacement of the face HOe of the additional floating member HN toward the axial billet side ADB is restricted by a face HNb facing the axial anti-billet side ADB on the outer peripheral surface of the inner peripheral member HOL of the fixed member HO. The face HNb of the fixed member HO is located closer to the axial billet side ADB than the face HOf of the fixed member HO. In this manner, in this embodiment, the main body elastic part HE of the pressurizer-side holder HP (FIG. 7) is configured to be able to apply elastic force between the floating part HY and the fixed part HO via the additional floating part HN, thereby elastically connecting the floating part HY and the fixed part HO. In the holder HP, the main body elastic part HE may be in a state compressed in the axial direction AD when the holder HP is in its natural state (FIG. 7), and therefore the floating part HY may be biased by the main body elastic part HE toward the billet side ADB in the axial direction.

[0031] 3 and 7 are merely examples, and the configurations of the holders HM and HP may be different from those in this example. For example, both the holders HM and HP may have the same configuration as the holder HM in this example.

[0032] Here, an example of the operation of the billet rotation and holding device S ( FIG. 1 ) according to this embodiment, configured as described above, will be described. First, the motor shaft MS of the electric motor M and the pressurizing shaft PS of the pressurizing device P are positioned in advance so that their respective central axes MSO and HPO are aligned substantially on the same straight line. At this time, the distance between the motor shaft MS and the pressurizing shaft PS is set to be longer than the length of the billet B. The billet B is then transported between the motor shaft MS and the pressurizing shaft PS. The billet B may be transported between the motor shaft MS and the pressurizing shaft PS using any device or manually. The transport direction (movement direction) of the billet B when transporting it between the motor shaft MS and the pressurizing shaft PS may be any. For example, the billet B may be positioned between the motor shaft MS and the pressurizing shaft PS by moving the billet B toward the first longitudinal side VD1, the depth direction DD, or the second longitudinal side VD2. With the billet B positioned between the motor shaft MS and the pressurizer shaft PS, the pressurizer shaft PS is displaced toward the axial first side AD1, bringing the holding surfaces HS of the motor-side holder HM and the pressurizer-side holder HP of the billet holding unit U into contact with the corresponding end surface Bf of the billet B. Thereafter, while the pressurizer shaft PS is further displaced toward the axial first side AD1, a pressure force is output from the pressurizer shaft PS toward the axial first side AD1, thereby increasing the pressure force (clamping force) acting between the holding surfaces HS of the motor-side holder HM and the pressurizer-side holder HP, and ultimately compressing the billet B. Then, when the pressure force (clamping force) becomes sufficiently large, the billet B is firmly held (clamped) by the holders HM and HP without slipping off, and the motor shaft MS is then rotated by the motor M. The rotational torque output from the motor shaft MS is transmitted in sequence to the fixed portion HO of the motor-side holder HM, the floating portion HY of the motor-side holder HM, the billet B, the floating portion HY of the pressurizer-side holder HP, the fixed portion HO of the pressurizer-side holder HP, and the pressurizer shaft PS, causing these to rotate in conjunction with the motor shaft MS. While the billet B is being rotated, the magnetic field generating device J generates a magnetic field in a predetermined working space J6 in which the billet B is located.During this time, the billet B is heated by an induced current flowing within the billet B. The billet B heated by the billet rotating and holding device S is then transported to a processing machine such as an extruder, and subjected to processing such as extrusion.

[0033] In this embodiment, as described above, the floating portion HY is configured to be able to float in the axial direction AD within the internal space HOh of the fixed portion HO, and the main body elastic portion HE, which is made up of one or more disc springs HD, is arranged approximately coaxially with the fixed portion HO, between the fixed portion HO and the floating portion HY, within the internal space HOh of the fixed portion HO. As a result, as illustrated schematically and exaggeratedly in Figures 9(d) to 9(f), the floating portion HY (and therefore the holding surface HS) can tilt relative to the fixed portion HO while receiving an elastic force from the main body elastic portion HE, so that the central axis of the floating portion HY is inclined relative to the central axis of the fixed portion HO. Therefore, even if the end face Bf of the billet B is inclined non-perpendicularly with respect to the central axis BO of the billet B, the holders HM, HP firmly contact the end face Bf of the billet B with the holding surfaces HS of the floating parts HY inclined with respect to the fixed parts HO, and can firmly hold both end faces Bf of the billet B by the pressure force from the pressurizing shaft PS and the elastic force from the main body elastic part HE. In other words, the billet holding unit U is configured to absorb errors in the inclination (shape errors) of both end faces Bf of the billet B. In this way, the billet rotating and holding device S can rotate the billet B while firmly holding both ends, even if the end face Bf of the billet B is inclined, and can reduce the error between the mechanical central axis and the rotation axis of the billet B, thereby reducing unbalance vibration. Furthermore, according to the above-described configuration of this embodiment, even if there is a misalignment such that the central axis MSO of the motor shaft MS (and thus the central axis of the fixed part HO of the motor-side holder HM) and the central axis PSO of the pressurizer shaft PS (and thus the central axis of the fixed part HO of the pressurizer-side holder) are not on exactly the same straight line (for example, if the two axes are parallel but deviated in the vertical direction VD and / or the depth direction DD ( FIG. 9( d) ) or if the two axes are non-parallel ( FIGS. 9( e ) and 9( f )), the misalignment can be absorbed by the floating part HY being appropriately inclined with respect to the fixed part HO. Therefore, the billet B can be rotated while both ends are firmly held in close contact with each other, and the error between the mechanical central axis of the billet B and the axis of rotation can be reduced, thereby reducing unbalance vibration.This in turn can prevent the billet B from falling off or being damaged. Furthermore, when the billet B is heated while being rotated as in the embodiment of FIG. 1 , a decrease in the ability to heat the billet B can also be prevented. Furthermore, when the billet B is heated while being rotated as in the embodiment of FIG. 1 , the length of the billet B may change during rotation. However, according to the configuration of this embodiment, the floating portion HY (and thus the holding surface HS) is movable in the axial direction AD relative to the fixed portion HO while receiving an elastic force from the main body elastic portion HE. Therefore, the billet B can be rotated while both ends are firmly held in close contact with each other while stably following such changes in the length of the billet B ( FIGS. 9( a ) to 9 ( c )).

[0034] In each example described herein, it is preferable that the holding surface HS of the motor-side holding fixture HM has a plurality of recessed stripes HG and a plurality of raised stripes HR, as illustrated in Fig. 2. The recessed stripes HG are recessed toward the axially opposite billet side ADA. The raised stripes HR protrude toward the axially opposite billet side ADB. These recessed stripes HG and raised stripes HR each extend approximately radially and are arranged alternately one by one along the circumferential direction. This allows the end surface Bf of the billet B to be engaged with the unevenness of the holding surface HS, which is made up of the raised stripes HR and recessed stripes HG, while the billet B is pressed against the holding surface HS by the pressure force from the press shaft PS, as illustrated in Fig. 4. As a result, unlike a case where the holding surface HS has no irregularities, torque from the motor shaft MS can be transmitted not only by frictional engagement between the holding surface HS of the motor-side holder HM and the billet B, but also by mechanical engagement between the irregularities on the holding surface HS of the motor-side holder HM and the billet B, thereby improving the efficiency of torque transmission between the holding surface HS of the motor-side holder HM and the billet B. As can be seen from FIG. 4 , each ridge HR preferably has a substantially triangular or trapezoidal shape in a circumferential cross section that protrudes toward the billet side ADB in the axial direction. In this case, the opening angle α ( FIG. 4 ) of each ridge HR is preferably 55° to 65°, for example, and more preferably 60°. This further improves the efficiency of torque transmission between the holding surface HS of the motor-side holder HM and the billet B. Similarly, as can be seen from FIG. 4, each groove HG preferably has a substantially triangular or trapezoidal shape in a cross section along the circumferential direction, recessed toward the axial side ADA of the billet opposite the axial side.

[0035] On the holding surface HS of the motor-side holding fixture HM, it is preferable that the protruding tip edge HRT of each ridge HR on the axial billet side ADB extends radially inward toward the axial anti-billet side ADA, as shown in Fig. 3. This allows the end face Bf of the billet B to bite into the irregularities formed by the ridges HR and grooves HG on the holding surface HS from the outer periphery (and therefore the high-torque side) of each ridge HR on the holding surface HS of the motor-side holding fixture HM during rotation of the billet B, and promotes the central axis of the billet B to approach (be centered) the central axis of the billet B to the central axis of the holding surface HS of the motor-side holding fixture HM. This further improves the torque transmission efficiency between the holding surface HS of the motor-side holding fixture HM and the billet B, and reduces the error between the mechanical central axis of the billet B and the axis of rotation, thereby reducing unbalance vibration. This in turn can prevent the billet B from shifting, falling off, or being damaged. Furthermore, the outer circumference can be made smaller than that of conventional chucks. In the holding surface HS of the motor-side holding fixture HM, the bottom edge HGB of the axially opposite side ADA of each groove HG may extend radially inward toward the axial billet side ADB, as shown in FIG. 3 . However, the holding surface HS of the motor-side holding fixture HM may be substantially flat (substantially parallel to the axial direction) over almost the entire holding surface HS, without the protrusions HR and grooves HG, as in the holding surface HS of the pressurizer-side holding fixture HP shown in FIG. 6 . The grooves formed by the convex ribs HR and concave ribs HG are formed by machining a mortar-shaped surface with various cutting tools with angled cutting edges to form linear one-dimensional grooves, which can be achieved in combination with equal pitch control on an indexing table. This method is highly productive and is thought to be cheaper than two-dimensional or three-dimensional machining to form the grooves.

[0036] As illustrated in FIG. 6, the holding surface HS of the pressurizer-side holding fixture HP may not be provided with the ridges HR and grooves HG, and may be substantially flat (substantially parallel to the axis-perpendicular direction) over almost the entire holding surface HS.

[0037] As illustrated in Figures 2 and 6, each of the holders HM and HP may have a guide protrusion HC on the outer circumferential side of the holding surface HS, protruding further toward the billet side ADB in the axial direction than the holding surface HS. The guide protrusion HC preferably extends circumferentially. The guide protrusion HC may extend continuously around the entire circumference, as in the example of Figure 6, or may extend intermittently in the circumferential direction, as in the example of Figure 2. The presence of the guide protrusion HC makes it easier to position the billet B on the inner circumferential side of the guide protrusion HC when placing the billet B between the holders HM and HP. This in turn makes it easier to position the billet B so that the central axis BO of the billet B is aligned substantially in the same line as the central axes HMO and HPO of the holders HM and HP. Furthermore, this prevents the billet B from falling off the holding surface HS or becoming misaligned.

[0038] When the holding surface HS of the motor-side holding tool HM has the irregularities formed by the ridges HR and the grooves HG as described above, it is preferable that the motor-side holding tool HM has a pushing portion HK (FIGS. 3 and 4). The pushing portion HK is configured to protrude beyond the holding surface HS (preferably, from the protruding tip edge HRT of the ridges HR) toward the axial second side AD2 (FIG. 3) when a force applied from the billet B toward the first axial side AD1 to the holding surface HS (specifically, a force applied from the pressurizing shaft PS to the holding surface HS of the motor-side holding tool HM via the pressurizing tool HP and the billet B toward the first axial side AD1) becomes equal to or less than a predetermined value, thereby pushing the billet B toward the second axial side AD2 and thereby separating the billet B from the holding surface HS. In the motor-side holder HM shown in the example of FIGS. 3 and 4 , the pusher portion HK is disposed within an internal space HYh defined on the central axis HMO of the floating portion HY. The internal space HYh is open at least on the axial billet side ADB (both sides of the axial direction AD in the illustrated example). The pusher portion HK is configured to be movable within the internal space HYh in the axial direction AD. The pusher portion HK has a protrusion HKP protruding outwardly along its extension in the axial direction AD. An elastic portion HKE for the pusher portion is provided within the internal space HYh of the floating portion HY between a surface HKsa on the axial anti-billet side ADA of the protrusion portion HKP of the pusher portion HK and a surface HYse on the inner peripheral surface defining the internal space HYh in the floating portion HY, which faces the axial billet side ADB and is positioned further on the axial anti-billet side ADA than the surface HKsa. The push portion elastic member HKE is composed of one or more disc springs HKD arranged approximately coaxially with the floating member HY. The face HKsb on the axial billet side ADB of the protrusion HKP of the push portion HK is regulated from further movement toward the axial billet side ADB by a face HYsf that faces the axial anti-billet side ADA on the inner circumferential surface that defines the internal space HYh in the floating member HY and is located closer to the axial billet side ADB than the face HYse.While the force applied from the billet B to the holding surface HS toward the axial first side AD1 exceeds a predetermined value (Figure 4), the tip surface HKT of the axial billet side ADB of the extrusion portion HK is pushed toward the axial first side AD1 by the end surface Bf of the billet B to approximately the same position as the holding surface HS in the axial direction AD, against the biasing force applied to the extrusion portion HK by the elastic portion HKE for the extrusion portion. On the other hand, when the force applied from the billet B to the holding surface HS toward the first axial side AD1 falls below a predetermined value (for example, the biasing force on the extrusion portion HK by the elastic part for extrusion portion HKE) (Figure 3), the biasing force of the elastic part for extrusion portion HKE causes the tip surface HKT of the axial billet side ADB of the extrusion portion HK to protrude toward the second axial side AD2 beyond the holding surface HS (preferably, the protruding tip edge HRT of the convex rib HR) (Figure 3), thereby pushing the billet B toward the second axial side AD2 and ultimately causing the billet B to separate from the holding surface HS. The presence of the push-out portion HK allows the billet holding unit U to temporarily hold the billet B, and after the end face Bf of the billet B bites into the unevenness consisting of the ridges HR and recesses HG provided on the holding surface HS of the motor-side holding fixture HM (FIG. 4), the push-out portion HK can easily release the billet B from the unevenness consisting of the ridges HR and recesses HG provided on the holding surface HS. Note that, when the motor-side holding fixture HM has guide projections HC as in this example, it is preferable that the tip face HKT on the axial billet side ADB of the push-out portion HK be displaceable toward the second axial side AD2 beyond the protruding tip edge HCT of the guide projection HC on the second axial side AD2 (FIG. 3).

[0039] Each of the holders HM, HP may be configured such that the engaging portion HYE of the floating portion HY and the engaged portion HOE of the fixed portion HO form a gear coupling, as in the modified example shown in Fig. 10. That is, for example, the surface HYsd of the engaging portion HYE facing the outer periphery may be a curved surface that is convexly curved toward the outer periphery in the axial cross section (Fig. 10). This makes it easier for the floating portion HY to tilt relative to the fixed portion HO.

[0040] The billet rotating and holding device and billet holding unit according to the present invention can be used for any purpose, for example, as a billet heating device for heating a billet (e.g., an aluminum billet).

[0041] S Billet rotation holding device M Electric motor MS Motor shaft MSO Central axis of the motor shaft P Pressurizer PS Pressurizer shaft PSO Central axis of the pressurizer shaft J Magnetic field generator J2 Iron core J4 Vacuum insulated container J6 Designated work space TA, TB, TC Support stand U Billet holding unit HM Motor side holding tool (holding tool) HMO Central axis of the motor side holding tool HP Pressurizer side holding tool (holding tool) HPO Central axis of the pressurizer side holding tool HO Fixed part HOh Internal space HOsa, HOsb, HOsc, HOsd, HOf Surface HOE Engaged part HOH Outer cylinder part HOL Inner circumference part HY Floating part (main body floating part) HYsa, HYsb, HYsc, HYsd, HYse, HYsf Surface HYE Engagement portion HS Holding surface HG Concave ridge HGB Bottom edge of concave ridge HR Convex ridge HRT Protruding tip edge of convex ridge HC Guide protrusion HCT Protruding tip edge of guide protrusion HYh Internal space HE Main body elastic portion HEA, HEB Partial elastic portion HD Disc spring HK Extrusion portion HKT Tip surface HKP Protrusion portion HKsa, HKsb Step surface HKE Elastic portion for extrusion portion HKD Disc spring HN Additional floating portion HNa, HNb, HNc Surface B Billet Bf End face in axial direction BO Central axis of billet AD Axial direction AD1 First axial side AD2: Second axial side ADB: Axial billet side ADA: Anti-billet side in the axial direction VD: Longitudinal direction VD1: First longitudinal side VD2: Second longitudinal side DD: Depth direction

Claims

1. A billet rotating and holding device configured to rotate a billet while holding it, comprising: an electric motor having an electric motor shaft; a pressurizer having a pressurizer shaft arranged axially opposite the electric motor shaft; and a billet holding unit, wherein the billet holding unit comprises: an electric motor side holding tool attached to the electric motor shaft and configured to hold an end face of the billet on a first axial side; and a pressurizer side holding tool attached to the pressurizer shaft and configured to hold an end face of the billet on a second axial side; the pressurizer is configured to output a pressure force toward the first axial side via the pressurizer shaft, and the billet holding unit is configured to clamp both axial end faces of the billet by the electric motor side holding tool and the pressurizer side holding tool using the pressure force toward the first axial side output from the pressurizer shaft, and the electric motor side holding tool and the pressurizer side holding tool each comprise: A billet rotation and holding device comprising: a fixed part configured to be fixed to the electric motor shaft or the pressurizing machine shaft and having an internal space that is open at least on the axial billet side; a floating part configured to be able to move freely in the axial direction within the internal space of the fixed part, configured to be able to transmit rotational torque between the fixed part and the floating part, and having a holding surface on the axial billet side configured to hold the end face of the billet on the first axial side or the second axial side; and a main body elastic part consisting of one or more disc springs arranged approximately coaxially with the fixed part between the fixed part and the floating part within the internal space of the fixed part.

2. The billet rotation holding device described in claim 1, wherein the electric motor side holding tool and the pressurizing machine side holding tool each have an outer peripheral surface of the floating part that is configured to be convex or concave in the radial direction and has a plurality of engaging parts that are arranged along the circumferential direction, and the inner peripheral surface that defines the internal space in the fixed part has a plurality of engaged parts that are configured to be concave or convex in the radial direction and are arranged along the circumferential direction and engage with the plurality of engaging parts, and the engagement between the plurality of engaging parts and the plurality of engaged parts makes it possible to transmit rotational torque between the fixed part and the floating part.

3. A billet rotating and holding device as set forth in claim 1, wherein the holding surfaces of the electric motor side holding fixture each have concave and convex strips extending approximately radially and arranged alternately along the circumferential direction.

4. A billet rotating and holding device as set forth in claim 3, wherein the protruding tip edge of each of the ridges on the axial billet side extends radially inward and toward the axial opposite side of the billet.

5. A billet rotating and holding device as described in claim 3, wherein the motor side holding tool has an extrusion portion configured to protrude beyond the holding surface toward the second axial direction and push the billet toward the second axial direction when the force applied from the billet to the holding surface toward the first axial direction falls below a predetermined value.

6. A billet rotating and holding device as described in claim 1, further comprising a magnetic field generating device configured to generate a magnetic field in a predetermined working space, wherein the billet rotating and holding device is configured to rotate the billet while holding the billet so that the billet is positioned within the predetermined working space, and to generate a magnetic field in the predetermined working space using the magnetic field generating device, and to heat the billet by an induced current flowing within the billet during this time.

7. A billet holding unit configured to be used in a billet rotating and holding device according to any one of claims 1 to 6.

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