JPWO2007063729A1 - Spline integrated linear motor - Google Patents

Abstract

The spline integrated linear motor 10 includes a spline shaft 11 in which a plurality of rolling element rolling grooves 12 extending in the axial direction are formed, and a spline outer cylinder in which a load rolling groove 22 corresponding to the rolling element rolling grooves 12 is formed. 21, and a plurality of balls 23 that are installed in a freely rolling manner in a load rolling path formed by the rolling element rolling grooves 12 and the load rolling grooves 22. The spline outer cylinder 21 becomes a magnetic field generating source by including the coil 24, and the spline shaft 11 becomes a field magnetic flux generating source by including the plurality of permanent magnets 13. The spline shaft 11 includes a plurality of rolling element rolling grooves 12 in the vicinity of a nonmagnetic member 14, and stainless steel, ceramics, high-hardness nonmagnetic free-cutting steel, titanium alloy, etc. are adopted as the nonmagnetic material. can do. By adopting such a configuration, it is possible to obtain a spline integrated linear motor having a high controllability and driving force transmission efficiency and having a compact shape.

Description

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

  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. The 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 a variable pump that is a pressure oil supply source.

  The hydraulic cylinder driven in this way is composed of a hydraulic cylinder body that performs an expansion and 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 extend and contract by receiving pressure oil supplied from a hydraulic pressure generator including a hydraulic pump and a 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 spaced apart 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 configuration in which a hydraulic cylinder main body and a hydraulic pressure generator are integrated is provided.

  However, since the hydraulic cylinder requires a relatively large hydraulic pressure generator separately from the hydraulic cylinder main body, there is a problem that the manufacturing cost and the maintenance / management cost at the time of introduction become high. 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. Could not be used. Furthermore, they also 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.

  Therefore, the applicant has made a diligent effort to create a new drive device that replaces the hydraulic cylinder (Japanese Patent Application No. 2005-244961). Such a drive device is a power transmission device having a structure in which a linear motor and a spline mechanism are combined. The advantage of the spline mechanism is that the drive force can be efficiently transmitted while having the advantage of the linear motor with high controllability. It also has.

Japanese Utility Model Publication No. 63-164603

  By the way, the applicant manufactures and sells motion guide devices as various power transmission mechanisms, and applies the power transmission device having a structure combining the linear motor and the motion guide mechanism as described above to a conventional motion guide device. A request to do so has arisen. In particular, since the spline device originally has a spline mechanism, if the linear motor can be accommodated in the spline device in a compact manner, such a device has very high utility in the industry. It becomes.

  However, it has been very difficult in the prior art to store the coil serving as the field magnetic flux generation source and the permanent magnet serving as the magnetic field generation source in a compact manner on the spline outer cylinder and the spline shaft, respectively. In particular, it is technically difficult to place a permanent magnet in a state where the influence on the generated magnetic field is reduced as much as possible for a spline shaft that receives a rolling load from a plurality of rolling elements such as balls.

  The present invention has been made in view of the existence of such problems, and its object is to provide a spline mechanism that can increase the transmission efficiency of driving force while having the advantage of a linear motor with high controllability. An object of the present invention is to provide a spline-integrated linear motor that has both advantages and a compact shape.

  A 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 spline outer cylinder in which a load rolling groove corresponding to the rolling element rolling grooves is formed. 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, and the spline outer cylinder includes a coil. And the spline shaft is provided with a plurality of permanent magnets and becomes 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 reciprocally movable relative to the axial direction of the spline shaft.

  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 a coil that includes the coil. It can be made up of.

  In the spline-integrated linear motor according to the present invention, each of the plurality of permanent magnets includes a plurality of notches, and 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 notches, and each of the plurality of recesses is provided with the nonmagnetic member in which at least one rolling element rolling groove is formed. can do.

  In the spline-integrated linear motor according to the present invention, 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 has at least one corner. It may be configured in a shape including R.

  In the spline-integrated linear motor according to the present invention, 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 an arc shape. Can be that.

  In the spline-integrated linear motor according to the present invention, portions appearing on the shaft surfaces of the plurality of permanent magnets constituting the spline shaft may be covered with a plate member.

  Furthermore, in the spline-integrated linear motor according to the present invention, the spline outer cylinder includes at least a portion in contact with the plurality of rolling elements including the vicinity of the load rolling groove. It is preferable that the 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 body are made of a material including at least stainless steel, ceramics, high-hardness nonmagnetic free-cutting steel, and titanium alloy. Can be that.

  The summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  According to the present invention, while having the advantage of a linear motor with high controllability, it also has the advantage of a spline mechanism that can increase the transmission efficiency of driving force, and has a compact shape, which is realized by the conventional technology It is possible to provide a completely new linear motor integrated with a spline, which has been impossible.

FIG. 1 is a partially cutaway front view for explaining the overall configuration of the spline integrated linear motor according to the present embodiment. FIG. 1A is a schematic diagram for explaining the operating principle of the spline integrated linear motor according to the present embodiment. FIG. 2 is a longitudinal sectional side view showing the AA section in FIG. 1. FIG. 3 is an external perspective view showing a state in which a plurality of permanent magnets according to the present embodiment are arranged in the axial direction of the spline shaft. 4 is a longitudinal sectional side view showing a BB cross section in FIG. 1. 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 sectional side view illustrating still another form of the spline shaft according to the present embodiment. FIG. 7 is a longitudinal cross-sectional view illustrating various modifications that the spline shaft according to the present embodiment can take. FIG. 8 is a vertical cross-sectional view illustrating a different form from FIG. 7 among various modifications that the spline shaft according to the present embodiment can take. FIG. 9 is a longitudinal sectional side view showing a CC section in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Spline integrated linear motor, 11 Spline shaft, 12 Rolling element rolling groove, 13 Permanent magnet, 14 Nonmagnetic member, 15 Notch part, 16 Recessed part, 17 Plate member, 18 End plate, 21 Spline outer cylinder, 21a Spline mechanism Part, 21b coil part, 22 load rolling groove, 23 ball, 24 coil, 33 magnetic material, 34 non-magnetic substance, α line of magnetic force.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. .

  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 is for explaining the operating principle of the spline integrated linear motor according to the present embodiment. FIG. 2 is a longitudinal sectional side view showing the AA cross section in FIG. 1, and FIG. 3 is an external perspective view showing a state in which a plurality of permanent magnets according to the present embodiment are arranged in the axial direction of the spline shaft. FIG. Further, FIG. 4 is a longitudinal sectional side view showing a BB section in FIG. 1.

  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 can freely reciprocate relative to the axial direction of the spline shaft 11. Device.

  A plurality of rolling element rolling grooves 12 extending in the axial direction are formed on the surface of the spline shaft 11. 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 are 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.

  On the other hand, the spline outer cylinder 21 includes a spline mechanism portion 21a installed at both ends of the substantially cylindrical outer cylinder and a coil portion 21b installed at a position sandwiched between the two spline mechanism portions 21a and 21a. It is configured.

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

  Moreover, the coil 24 is installed in the coil part 21b in the position spaced apart from the several permanent magnet 13 installed in the spline shaft 11 at suitable intervals. The coil 24 is a member that can serve as a magnetic field generation source by receiving power supplied from a power source (not shown) via a power cable (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 have the same polarity. The N pole and the N pole are stacked so as to face each other, that is, the S pole and the S pole face each other. On the other hand, with respect 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 different phases by 120 ° through a plurality of coils 24 divided into three phases of U, V, and W phases. By obtaining a thrust by the moving magnetic field generated in this way, the spline shaft 11 can be linearly moved relative to the spline outer cylinder 21 in synchronization with the speed of the moving magnetic field.

  In addition, since the spline outer cylinder 21 and the spline shaft 11 are devices that can reciprocate relatively with respect to the axial direction, either the spline outer cylinder 21 or the spline shaft 11 is set to the fixed side, and the other Can be set on the moving side. That is, the coil 24 according to the present embodiment can exhibit both a function as a fixed side coil and a function as a movable side coil according to the installation conditions of the spline integrated linear motor.

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

  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 stacked in the axial direction of the spline shaft 11, a plurality (four in FIG. 3) of notches 15 form a plurality of recesses 16 (four in FIG. 3) extending in the axial direction. And the spline shaft 11 which concerns on this embodiment is completed by installing the nonmagnetic member 14 in which the rolling-element rolling groove 12 was formed with respect to this recessed part 16. FIG.

  In addition, as a method of installing the nonmagnetic member 14 with respect to the concave portion 16, a method is adopted in which the plurality of permanent magnets 13 are stacked as described above, and then the concave portion 16 and the nonmagnetic member 14 are adhesively bonded using an adhesive. can do. Further, in FIG. 1, end plates 18 and 18 installed at both shaft ends of the spline shaft 11 are prepared. First, the nonmagnetic member 14 is first installed on the end plate 18 on one end side to form a bowl shape. It is also possible to adopt a method of assembling the spline shaft 11 by creating a member of the above, then stacking a plurality of permanent magnets 13 in the saddle shape, and finally installing an end plate 18 on the other end side.

  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 functions and effects. That is, in the present embodiment, a non-magnetic member 14 that can accept a rolling load from the ball 23 that is difficult only with the permanent magnet 13 and that does not interfere with the field flux generated from the permanent magnet 13 is adopted for the spline shaft 11. Furthermore, since the permanent magnet 13 and the nonmagnetic member 14 are arranged so as to overlap with each other in the circumferential direction of the spline shaft 11, the transmission efficiency of the driving force can be improved while having the advantage of the linear motor of high controllability. It has become possible to provide a completely new spline-integrated linear motor that has the advantages of a spline mechanism and has a compact shape, which cannot be realized by the prior art.

  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 covered with a plate member 17 made of a nonmagnetic material. It is preferable to do. Since the permanent magnet 13 can be protected by adopting the plate member 17, the life of the apparatus can be extended.

  However, various aspects can be adopted for the configuration of the spline shaft 11 according to the above-described embodiment. For example, FIG. 5 is a vertical cross-sectional side view illustrating a form different from the spline shaft 11 according to the present embodiment described above, but the spline shaft 11 illustrated in FIG. When viewed in a cross section perpendicular to the vertical direction (the same cross section as the AA cross section in FIG. 1), the boundary shape between the plurality of recesses 16 and the nonmagnetic member 14 is at least one (two in FIG. 5). The shape including the corner R can be used. By making the boundary R between the recess 16 and the nonmagnetic member 14 include the corner R, a singular point with respect to the magnetic flux can be eliminated, and the field magnetic flux generated by the spline shaft 11 can be efficiently generated by the coil on the spline outer cylinder 21 side. 24.

  Further, regarding the boundary shape 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 AA cross section in FIG. 1), An arc shape as shown in FIG. 6 is also preferable. Here, FIG. 6 is a longitudinal sectional side view illustrating still another form of the spline shaft 11 according to the present embodiment. This arc shape is a device for preventing the rolling load repeatedly exerted on 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 arc shape. The load can be distributed and the life of the spline shaft 11 can be extended.

  Furthermore, the spline shaft 11 according to the present embodiment can adopt a further suitable modification. For example, the spline integrated linear according to the present embodiment in a use environment in which the permanent magnet 13 does not need to be protected. When the motor 10 is used, as shown in FIG. 7, the plate member 17 can be omitted, and the spline shaft 11 can be constituted by the permanent magnet 13 and the nonmagnetic member 14.

  Further, in the present embodiment, the case where a complicated magnet shape in which the permanent magnet 13 includes a plurality of notches 15 is illustrated and described, but the cross-sectional shape of the permanent magnet 13 is simplified as shown in FIG. The nonmagnetic member 14 may be arranged so as to surround the permanent magnet 13 having a circular cross section.

  As described above, various suitable forms that the spline shaft 11 according to the present embodiment can take have been described. However, in the spline integrated linear motor 10 according to the present embodiment, a new feature is also added to the spline outer cylinder 21 side, Suitable improvements can be made. Such an improvement will be described with reference to FIG. Here, FIG. 9 is a vertical cross-sectional side view showing a CC cross section of the spline outer cylinder 21 in FIG.

  In the spline outer cylinder 21 shown in FIG. 9, at least a portion in contact with the plurality of balls 23 including the vicinity of the load rolling groove 22 is configured by a nonmagnetic material 34. In addition, a magnetic material 33 is disposed in a portion other than the nonmagnetic material 34 installed so as to surround the plurality of balls 23. That is, since the magnetic material 33 is disposed so as to cover the place where the nonmagnetic material 34 is located, a magnetic shield is formed at the place where the ball 23 circulates. Therefore, since the magnetic field lines indicated by the symbol α flow avoiding the plurality of balls 23 as shown in FIG. 9, the balls 23 are not magnetized by the field magnetic flux generated from the permanent magnet 13. Therefore, according to the spline outer cylinder 21 of the form illustrated in FIG. 9, the adverse effect on the rolling motion of the ball 23 due to the magnetization of the ball 23 can be eliminated, so that a smooth and stable operation is performed. Therefore, it is possible to realize the spline integrated linear motor 10 capable of performing the above.

  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, high hardness nonmagnetic free magnetic material. It is possible to employ a material containing cutting steel or a titanium alloy.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the embodiment. For example, in the present embodiment, the case where four rolling element rolling grooves 12 are formed on the spline shaft 11 has been described as an example, but the number of rolling element rolling grooves 12 is set according to use conditions. It is possible to change.

  Moreover, although the case where the nonmagnetic member 14 according to the present embodiment includes a single rolling element rolling groove 12 has been described as an example, a plurality of rolling element rolling grooves 12 formed in the nonmagnetic member 14 are provided. It may be.

  Furthermore, in this embodiment, the case where the plate member 17 made of a non-magnetic material is employed for the purpose of protecting the outer peripheral surface of the permanent magnet 13 has been described as an example, but when the function as a linear motor can be secured, It is also possible to employ a plate member 17 made of a metal material.

  Furthermore, in the present embodiment, as an installation method of the nonmagnetic member 14 with respect to the recess 16, the case where the method of adhesively bonding the recess 16 and the nonmagnetic member 14 using an adhesive is described as an example. Any other joining method such as caulking joining can be employed.

  Furthermore, in the present embodiment, the case where the ball 23 is employed is described as an example of the rolling element used in the two spline mechanism portions 21a and 21a. However, a rolling element having another form such as a roller is employed. You can also. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

Claims (8)

A spline shaft formed with a plurality of rolling element rolling grooves extending in the axial direction;
A spline outer cylinder in which a load rolling groove corresponding to the rolling element rolling groove is formed;
A plurality of rolling elements installed in a freely rolling manner in a load rolling path formed by the rolling element rolling grooves and the load rolling grooves;
With
The spline outer cylinder becomes a magnetic field generation source by including a coil,
When the spline shaft is provided with a plurality of permanent magnets and becomes a field magnetic flux generation source, and the vicinity of the plurality of rolling element rolling grooves is constituted by a nonmagnetic member,
The spline-integrated linear motor, wherein the spline outer cylinder is reciprocally movable relative to the axial direction of the spline shaft. The spline integrated linear motor according to claim 1,
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;
A spline integrated linear motor characterized by comprising: 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,
The spline-integrated linear motor, wherein each of the plurality of recesses is provided with the nonmagnetic member in which at least one rolling element rolling groove is formed. 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. The spline integrated linear motor according to claim 3,
The spline integrated type, wherein 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 is formed in an arc shape Linear motor. The spline integrated linear motor according to any one of claims 1 to 5,
The spline-integrated linear motor is characterized in that portions appearing on shaft surfaces of the plurality of permanent magnets constituting the spline shaft are covered with a plate member. The spline integrated linear motor according to any one of claims 1 to 6,
The spline outer cylinder is configured by a non-magnetic material at least in contact with the plurality of rolling elements including the load rolling groove vicinity.
The spline-integrated linear motor, wherein the plurality of rolling elements are configured not to be magnetized by a field magnetic flux generated from the plurality of permanent magnets. In the spline integrated linear motor according to any one of claims 1 to 7,
The spline-integrated linear motor, wherein the nonmagnetic member, the plate member, and the nonmagnetic body are made of a material including at least stainless steel, ceramics, high-hardness nonmagnetic free-cutting steel, and titanium alloy.

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