WO2007063729A1

WO2007063729A1 - Linear motor integrating spline

Info

Publication number: WO2007063729A1
Application number: PCT/JP2006/323072
Authority: WO
Inventors: Toshiyuki Aso; Shuhei Yamanaka
Original assignee: Thk Co., Ltd.
Priority date: 2005-11-30
Filing date: 2006-11-20
Publication date: 2007-06-07
Also published as: JPWO2007063729A1

Abstract

A linear motor (10) integrating spline comprising a spline shaft (11) having a plurality of rolling element rolling grooves (12) extending in the axial direction, a spline outer tube (21) formed with load rolling grooves (22) corresponding to the rolling element rolling grooves (12), and a plurality of balls (23) arranged to roll freely in a load rolling passage formed by the rolling element rolling groove (12) and the load rolling groove (22). The spline outer tube (21) becomes a magnetic field generation source when it is provided with a coil (24), and the spline shaft (11) becomes a field flux generation source when it is provided with a plurality of permanent magnets (13). The spline shaft (11) is composed of a nonmagnetic member (14) at portions in the vicinity of the plurality of rolling element rolling grooves (12) wherein stainless steel, ceramics, high hardness nonmagnetic free cutting steel, or titanium alloy can be employed as the nonmagnetic material. A linear motor integrating spline having a compact profile and exhibiting high controllability and driving force transmission efficiency can be obtained by employing such an arrangement.

Description

Specification

Spline integrated linear motor

Technical field

[0001] The present invention relates to a technique for realizing an unprecedented spline integrated linear motor by combining a linear motor and a spline mechanism.

Background art

[0002] For example, a hydraulic cylinder is generally used as a drive device that realizes an expansion / contraction operation of a mechanical device such as an injection device of an injection molding machine or a link mechanism of a construction machine. A hydraulic cylinder is a device that realizes a wide speed range and thrust range while maximizing output by changing the pressure and flow rate of the pressure oil by changing the capacity of the variable pump that is the pressure oil supply source.

[0003] The hydraulic cylinder driven in this way is composed of a hydraulic cylinder body that performs an expansion / contraction operation and a hydraulic pressure generator that supplies pressure oil to the hydraulic cylinder body. The hydraulic cylinder body is configured to be able to perform expansion and contraction operations by receiving the supply of hydraulic oil from the hydraulic pressure generator, which is the force of a hydraulic pump or switching valve. And until now, the hydraulic cylinder main body and the hydraulic pressure generator constituting the hydraulic cylinder are arranged such that the hydraulic cylinder main body and the hydraulic pressure generator are separated from each other, and supply and discharge of pressure oil between the two through the hydraulic piping, As shown in the following Patent Document 1, a hydraulic cylinder body and a hydraulic pressure generator are integrally configured.

[0004] However, since the hydraulic cylinder requires a relatively large hydraulic pressure generating device separately from the hydraulic cylinder body, the manufacturing cost and the maintenance 'management cost at the time of introduction become high. Had. In addition, the hydraulic cylinder has a high output and can achieve a wide speed range and thrust range, but is not good at fine stop position control within the stroke, so it is a mechanical device that requires high controllability. It was a force that could not be used. In addition, it had environmental problems such as the generation of waste oil. Therefore, it has been desired to realize an electric drive device that is easy to control and clean from a hydraulic cylinder having such problems.

[0005] Therefore, the applicant has made diligent efforts to develop a new drive device to replace the hydraulic cylinder. (Japanese Patent Application No. 2005-244961). The powerful drive device is a power transmission device with a structure that combines a linear motor and a spline mechanism, and has the advantage of a linear motor with high controllability, while being able to efficiently transmit drive force. It also has the advantages of.

[0006] Patent Document 1: Japanese Utility Model Publication No. 63-164603

Disclosure of the invention

Problems to be solved by the invention

[0007] By the way, the applicant manufactures and sells motion guide devices as various power transmission mechanisms, and uses a power transmission device having a structure combining the linear motor and the motion guide mechanism as described above. There was a request to apply to the guidance device. In particular, since spline devices originally have a spline mechanism, if a linear motor can be accommodated in a spline device in a compact manner, such a device has very high V and usability in the industry. It will be prepared.

[0008] However, it is very difficult for the conventional technology to fit the coil serving as the field flux generation source and the permanent magnet serving as the magnetic field generation source into the spline outer cylinder and the spline shaft in a compact manner. there were. In particular, it is technically difficult to place a permanent magnet in a state where the influence on the generated magnetic field is minimized as much as possible with respect to the spline shaft that is also subjected to a rolling load by a plurality of rolling body forces such as balls.

[0009] The present invention has been made in view of the existence of a problem to be solved, and its object is to increase the transmission efficiency of driving force while having the advantage of a linear motor with high controllability. If you can

It is to provide a linear motor of a spline integrated type that has the advantages of the V and spline mechanism and has a compact force. Means for solving the problem

The spline integrated linear motor according to the present invention includes a spline shaft in which a plurality of rolling element rolling grooves extending in the axial direction are formed, and a load rolling groove corresponding to the rolling element rolling groove. A spline outer cylinder, and a plurality of rolling elements installed in a freely rolling manner in a load rolling path formed by the rolling element rolling groove and the load rolling groove, the spline outer cylinder, By providing a coil, it becomes a magnetic field generation source, and the spline shaft has a plurality of By providing a permanent magnet, it becomes a field magnetic flux generation source and the vicinity of the plurality of rolling element rolling grooves is constituted by a nonmagnetic member, so that the spline outer cylinder is relative to the axial direction of the spline shaft. It is characterized by reciprocating freely.

[0011] In the spline-integrated linear motor according to the present invention, the spline outer cylinder includes a spline mechanism that guides a relative reciprocating motion of the spline outer cylinder with respect to an axial direction of the spline shaft, and the coil. It can be assumed that the coil part and the cover are configured.

In the spline-integrated linear motor according to the present invention, each of the plurality of permanent magnets includes a plurality of notches, and is stacked in the axial direction of the plurality of permanent magnet forces S-spline shafts. Sometimes, a plurality of recesses extending in the axial direction are formed by the plurality of notches, and the nonmagnetic member in which at least one rolling element rolling groove is formed in each of the plurality of recesses. It can be assumed that it is installed.

[0013] The spline integrated linear motor according to the present invention has a boundary shape between the plurality of recesses and the nonmagnetic member when viewed in a cross section perpendicular to the axial direction of the spline shaft. It can be made up of shapes that contain at least one corner R

[0014] The spline-integrated linear motor according to the present invention has a boundary shape between the plurality of concave portions and the nonmagnetic member when viewed in a cross section perpendicular to the axial direction of the spline shaft. It may be configured in an arc shape.

[0015] Further, in the spline integrated linear motor according to the present invention, a portion appearing on the shaft surface of the plurality of permanent magnets constituting the spline shaft is covered with a plate member and is a TV. be able to.

Furthermore, in the spline-integrated linear motor according to the present invention, the spline outer cylinder includes at least a portion that contacts the plurality of rolling elements including the vicinity of the load rolling groove by a nonmagnetic material. It is preferable that the plurality of rolling elements are not magnetized by the field magnetic flux generated from the plurality of permanent magnets.

Furthermore, in the spline integrated linear motor according to the present invention, the nonmagnetic member, the plate member, and the nonmagnetic material are at least stainless steel, ceramics, It can be made of high-hardness nonmagnetic free-cutting steel or a material containing a titanium alloy.

[0018] It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention, and a sub-combination of these feature groups can also be an invention.

The invention's effect

[0019] According to the present invention, when having the advantage of a spline mechanism that can increase the transmission efficiency of the driving force while having the advantage of the linear motor of high controllability, the force is also provided with a compact shape. In this way, it is possible to provide a completely new spline-integrated linear motor that was not possible with the conventional technology. Brief Description of Drawings

FIG. 1 is a partially cutaway front view for explaining the overall configuration of a spline integrated linear motor according to the present embodiment.

FIG. 1A is a schematic diagram for explaining the operating principle of a spline integrated linear motor according to the present embodiment.

2 is a longitudinal sectional side view showing the AA cross section in FIG. 1. FIG.

FIG. 3 is an external perspective view showing a state in which a plurality of permanent magnet force spline shafts according to the present embodiment are arranged in the axial direction.

FIG. 4 is a longitudinal sectional side view showing a BB cross section in FIG.

FIG. 5 is a vertical cross-sectional side view illustrating a form different from the spline shaft according to the present embodiment.

FIG. 6 is a longitudinal cross-sectional side view illustrating still another form of the spline shaft according to the present embodiment.

FIG. 7 is a vertical cross-sectional view illustrating various modifications that the spline shaft according to the present embodiment can take.

FIG. 8 is a longitudinal sectional view illustrating another form different from FIG. 7 among various modifications that can be adopted by the spline shaft according to the present embodiment.

FIG. 9 is a longitudinal sectional side view showing a CC cross section in FIG. 1.

Explanation of symbols [0021] 10 spline integrated linear motor, 11 spline shaft, 12 rolling element rolling groove, 13 permanent magnet, 14 nonmagnetic member, 15 notch, 16 recess, 17 plate member, 18 end plate, 21 spline outer cylinder , 21a Spline mechanism, 21b Coil, 22 Load rolling groove, 23 Ball, 24 coil, 33 Magnetic material, 34 Non-magnetic material, a Magnetic field line.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiments are not intended to limit the invention according to each claim, and are also described in the embodiments! All combinations of features are essential to the solution of the invention. Not exclusively.

FIG. 1 is a partially broken front view for explaining the overall configuration of the spline integrated linear motor according to the present embodiment, and FIG. 1A shows the operation of the spline integrated linear motor according to the present embodiment. It is a schematic diagram for demonstrating a principle. FIG. 2 is a vertical cross-sectional side view showing a cross section AA in FIG. 1, and FIG. 3 shows a state in which a plurality of permanent magnet capsule shafts according to the present embodiment are arranged in the axial direction. It is an external perspective view. Further, FIG. 4 is a longitudinal sectional side view showing a BB section in FIG.

The spline integrated linear motor 10 according to the present embodiment includes a spline shaft 11 and a spline outer cylinder 21, and the spline outer cylinder 21 reciprocates relative to the axial direction of the spline shaft 11. It is a device that can be freely used.

A plurality of rolling element rolling grooves 12 extending in the axial direction are formed on the surface of the spline shaft 11. In addition, a plurality of permanent magnets 13 are installed on the spline shaft 11, and the plurality of permanent magnets 13 serve as a field magnetic flux generation source. The plurality of permanent magnets 13 are stacked in the axial direction of the spline shaft 11 and fixed to each other, and the permanent magnets 13 adjacent to each other are installed so that the polarities of the mutually facing surfaces are the same.

[0026] On the other hand, the spline outer cylinder 21 includes a spline mechanism part 21a installed at both ends of the substantially cylindrical outer cylinder, and a coil part installed at a position sandwiched between the two spline mechanism parts 21a and 21a. 21b and force are composed.

Of these, the spline mechanism portion 21a has rolling element rolling grooves 1 formed on the spline shaft 11. A load rolling groove 22 corresponding to 2 is formed, and a plurality of balls 23 are installed. The plurality of balls 23 are members that are freely installed in a load rolling path formed by the rolling element rolling groove 12 on the spline shaft 11 side and the load rolling groove 22 on the spline mechanism 21 a side. is there. Therefore, the spline shaft 11 and the two spline mechanism portions 21a, 21a constitute a so-called ball spline device, and the smooth relative reciprocating linear motion of the spline outer cylinder 21 with respect to the spline shaft 11 is realized.

[0028] Further, in the coil portion 21b, a coil 24 is installed at a position spaced apart from a plurality of permanent magnets 13 installed on the spline shaft 11. The coil 24 is a member that can play a role as a magnetic field generation source by receiving power supply via a power cable (not shown) (not shown).

Here, the operation principle of the spline integrated linear motor according to the present embodiment will be described with reference to FIG. 1A. As described above, the plurality of permanent magnets 13 installed on the spline shaft 11 are as follows. They are stacked so that the same poles face each other, that is, the N poles, N poles, and the S poles and S poles face each other. On the other hand, with regard to the coil 24, a set of three-phase coils that form a U'V'W phase by three is the smallest installation unit, and a coil unit is formed by combining a plurality of these three-phase coils. A moving magnetic field that moves in the axial direction of the coil 24 can be generated by flowing a three-phase current having a phase difference of 120 ° by a plurality of coils 24 divided into three phases of U′V′W phase. By obtaining a thrust from the moving magnetic field generated in this way, the spline shaft 11 can move linearly relative to the spline outer cylinder 21 in synchronization with the speed of the moving magnetic field.

[0030] Since the spline outer cylinder 21 and the spline shaft 11 are devices that can reciprocate relatively with respect to the axial direction, one of the displacement between the spline outer cylinder 21 and the spline shaft 11 is prevented. The other side can be set on the fixed side and the other side on the moving side. That is, the coil 24 according to the present embodiment can also exhibit a deviation in the function as the fixed side coil and the function as the movable side coil according to the installation conditions of the spline integrated linear motor. Talk to you.

[0031] While the configuration of the spline integrated linear motor 10 according to the present embodiment has been described above, the spline integrated linear motor 10 according to the present embodiment has further preferable characteristic points. Yes. This feature point will be described with reference to FIG. 2. In this embodiment, a plurality (four in FIG. 2) of the rolling element rolling grooves 12 formed on the spline shaft 11 constituting the spline integrated linear motor 10 are formed. It can be seen that the vicinity is composed of a member different from the permanent magnet 13. The member having the rolling element rolling groove 12 is a non-magnetic member 14 made of a non-magnetic material, which can withstand a rolling load repeatedly received from a plurality of balls 23 and a permanent magnet 13 serving as a field magnetic flux generation source. It is possible to transmit the magnetic force from the coil 24 and apply it to the coil 24 side.

[0032] As a specific configuration of the spline shaft 11, each of the plurality of permanent magnets 13 constituting the spline shaft 11 includes a plurality of notches 15, and as shown in FIG. When the permanent magnets 13 are stacked in the axial direction of the spline shaft 11, a plurality of (four in FIG. 3) notches 15 form a plurality of recesses 16 (four in FIG. 3) extending in the axial direction. become. The spline shaft 11 according to this embodiment is completed by installing the nonmagnetic member 14 in which the rolling element rolling grooves 12 are formed in the recess 16.

[0033] As a method for installing the nonmagnetic member 14 in the recess 16, the plurality of permanent magnets 13 are stacked as described above, and the recess 16 and the nonmagnetic member 14 are bonded and bonded using an adhesive. The method can be adopted. In addition, as shown in Fig. 1, end plates 18 and 18 that are installed at both shaft ends of the spline shaft 11 are prepared, and a non-magnetic member 14 is first installed on the end plate 18 on one end side to form a vertical type It is also possible to use a method of assembling the spline shaft 11 by creating a shaped member, then stacking a plurality of permanent magnets 13 in this saddle shape, and finally installing an end plate 18 on the other end side .

[0034] When the spline shaft 11 has the above-described configuration, the spline-integrated linear motor 10 according to the present embodiment can exhibit various suitable effects. In other words, in the present embodiment, the non-magnetic member 14 that can accept the rolling load from the ball 23, which was difficult with only the permanent magnet 13, and does not interfere with the field flux generated from the permanent magnet 13, is connected to the spline shaft 11. In addition, the permanent magnet 13 and the nonmagnetic member 14 are arranged so as to overlap each other in the circumferential direction of the spline shaft 11, so that it has high controllability and has the advantages of a linear motor, while also having a driving force. Combined with the advantages of a spline mechanism that can increase transmission efficiency, and with a compact shape that is impossible to achieve with conventional technology It has become possible to provide a completely new linear motor integrated with a spline.

In the spline shaft 11 according to the present embodiment, as shown in FIG. 2, portions appearing on the shaft surfaces of the plurality of permanent magnets 13 constituting the spline shaft 11 are formed by a plate member 17 made of a nonmagnetic material. It is preferable to cover. Since the permanent magnet 13 can be protected by using the plate member 17, the life of the apparatus can be extended.

However, according to the configuration of the spline shaft 11 according to the present embodiment described above, various modes can be adopted. For example, FIG. 5 is a vertical cross-sectional side view illustrating another form different from the spline shaft 11 according to the present embodiment described above, but the spline shaft 11 illustrated in FIG. At least one boundary shape force between the multiple recesses 16 and the non-magnetic member 14 when viewed in a cross section perpendicular to the axial direction (the same cross section as the A—A cross section in FIG. 1) Then, it can be configured by a shape including two corners R. By including the corner R in the boundary shape between the concave portion 16 and the nonmagnetic member 14, the singular point with respect to the magnetic flux can be eliminated, and the field flux generated by the spline shaft 11 can be efficiently generated on the spline outer cylinder 21 side. It is possible to affect the coil 24.

[0037] Further, the boundary between the plurality of recesses 16 and the nonmagnetic member 14 when viewed in a cross section perpendicular to the axial direction of the spline shaft 11 (the same cross section as the A—A cross section in FIG. 1). The shape is preferably an arc shape as shown in FIG. Here, FIG. 6 is a vertical cross-sectional side view illustrating still another form of the spline shaft 11 according to the present embodiment. This circular arc shape is a device to prevent the rolling load repeatedly applied to the spline shaft 11 side by the ball 23 from being concentrated on a specific portion, and is exerted from the ball 23 to the permanent magnet 13 side by the effect of the circular arc shape. The load can be distributed and the life of the spline shaft 11 can be increased.

[0038] Further, it is possible to adopt a further preferable modified form for the spline shaft 11 according to the present embodiment. For example, the spline shaft 11 according to the present embodiment is used in an environment where it is not necessary to protect the permanent magnet 13. When the spline integrated linear motor 10 is used, as shown in FIG. 7, the plate member 17 is omitted, and the permanent magnet 13 and the nonmagnetic member 14 constitute the spline shaft 11. Can be achieved.

Further, in the present embodiment, the force described by exemplifying a case where a complicated magnet shape in which the permanent magnet 13 includes a plurality of notches 15 is employed, as shown in FIG. 8, the cross-sectional shape of the permanent magnet 13 The non-magnetic member 14 may be disposed so as to surround the permanent magnet 13 having a circular cross section.

As described above, various preferred forms that can be adopted by the spline shaft 11 according to the present embodiment have been described. However, the spline integrated linear motor 10 according to the present embodiment also has a new feature on the spline outer cylinder 21 side. It is possible to add and make suitable improvements. This improvement will be described with reference to FIG. Here, FIG. 9 is a vertical cross-sectional side view showing a CC cross section of a portion of the spline outer cylinder 21 in FIG.

In the spline outer cylinder 21 shown in FIG. 9, a portion that contacts at least a plurality of balls 23 including the vicinity of the load rolling groove 22 is constituted by a nonmagnetic material 34. In addition, a magnetic material 33 is disposed in a portion other than the non-magnetic material 34 installed so as to surround the plurality of balls 23. That is, the magnetic material 33 is disposed so as to cover the place where the non-magnetic material 34 is located, and therefore a magnetic shield is formed at the place where the ball 23 circulates. Therefore, the magnetic field lines indicated by the symbol α flow avoiding the plurality of balls 23 as shown in FIG. 9, so that the balls 23 are not magnetized by the field magnetic flux generated from the permanent magnet 13. Become. Therefore, according to the spline outer cylinder 21 of the form illustrated in FIG. 9, it is possible to eliminate an adverse effect on the rolling motion of the ball 23 due to the magnetic force of the ball 23, so that the smooth and stable It becomes possible to realize a spline-integrated linear motor 10 that can operate.

In the above-described spline integrated linear motor 10 according to the present embodiment, the nonmagnetic material constituting the nonmagnetic member 14, the plate member 17, and the nonmagnetic body 34 includes at least stainless steel, ceramics, It is possible to adopt materials including high-hardness nonmagnetic free-cutting steel and titanium alloys.

[0043] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Various modifications or improvements can be covered in the above embodiment. For example, in this embodiment, four spline shafts 11 The case where the rolling element rolling grooves 12 are formed has been described as an example, but the number of rolling element rolling grooves 12 can be changed depending on the use conditions.

Further, in the nonmagnetic member 14 according to the present embodiment, the case where the single rolling element rolling groove 12 is provided has been described as an example, but the rolling element rolling formed in the nonmagnetic member 14 is described. A plurality of grooves 12 may be provided.

Furthermore, in the present embodiment, the case where the plate member 17 made of a nonmagnetic material is employed for the purpose of protecting the outer peripheral surface of the permanent magnet 13 has been described as an example, but the function as a linear motor can be ensured. In this case, it is also possible to employ a plate member 17 having a metal material force.

Furthermore, in the present embodiment, as an installation method of the nonmagnetic member 14 with respect to the recess 16, an example in which a method of bonding the recess 16 and the nonmagnetic member 14 using an adhesive is employed will be described. However, it is possible to adopt any other joining method such as caulking joining.

Furthermore, in the present embodiment, the case where the ball 23 is adopted as the rolling element used in the two spline mechanism portions 21a and 21a has been described as an example. However, the rolling element having another form such as a roller is described. A moving body can also be employed. It is clear that the form in which such changes or improvements are added can also be included in the technical scope of the present invention, and the descriptive power of the claims.

Claims

The scope of the claims

[1] a spline shaft in which a plurality of rolling element rolling grooves extending in the axial direction are formed;

A spline outer cylinder in which a load rolling groove corresponding to the rolling element rolling groove is formed, and is installed in a freely rolling manner in a load rolling path formed by the rolling element rolling groove and the load rolling groove. A plurality of rolling elements

With

The spline outer cylinder becomes a magnetic field generation source by including a coil,

The spline shaft is provided with a plurality of permanent magnets and serves as a field magnetic flux generation source, and the vicinity of the plurality of rolling element rolling grooves is constituted by a nonmagnetic member, whereby the spline outer cylinder is connected to the spline shaft. A linear motor with integrated spline, characterized by its own reciprocal motion relative to the axial direction.

[2] The spline integrated linear motor according to claim 1, wherein

The spline outer cylinder is

A spline mechanism that guides the reciprocating motion of the spline outer cylinder relative to the axial direction of the spline shaft;

A coil portion comprising the coil;

Spline-integrated linear motor characterized in that force is also configured.

[3] The spline integrated linear motor according to claim 1 or 2,

Each of the plurality of permanent magnets includes a plurality of notches,

When the plurality of permanent magnets are stacked in the axial direction of the spline shaft, a plurality of recesses extending in the axial direction are formed by the plurality of notches,

Each of the plurality of recesses is provided with the non-magnetic member in which at least one rolling element rolling groove is formed.

[4] In the spline integrated linear motor according to claim 3,

The boundary shape between the plurality of recesses and the nonmagnetic member when viewed in a cross section perpendicular to the axial direction of the spline shaft is configured to include at least one corner R. Spline integrated linear motor.

[5] In the spline integrated linear motor according to claim 3, The spline-integrated type, wherein a boundary shape between the plurality of concave portions and the nonmagnetic member when viewed in a cross section perpendicular to the axial direction of the spline shaft is formed in an arc shape Linear motor.

[6] The spline-integrated linear motor according to any one of claims 1 to 5, wherein a portion appearing on a shaft surface of the plurality of permanent magnets constituting the spline shaft is covered with a plate member. Spline integrated linear motor.

[7] The spline-integrated linear motor as set forth in any one of claims 1 to 6, wherein the spline outer cylinder is nonmagnetic at least a portion in contact with the plurality of rolling elements including the vicinity of the load rolling groove. By being composed by the body,

2. The spline integrated linear motor according to claim 1, wherein the plurality of rolling elements are configured not to be magnetized by a field magnetic flux generated from the plurality of permanent magnets.

[8] The spline-integrated linear motor according to any one of claims 1 to 7, wherein the nonmagnetic member, the plate member, and the nonmagnetic body include at least stainless steel, ceramics, and high hardness nonmagnetic free cutting. A spline integrated linear motor characterized by being made of a material containing steel and titanium alloy.