JP6515346B2 - Method of manufacturing eddy current type reduction gear - Google Patents

Description

  The present invention relates to a reduction gear mounted on a vehicle such as a truck or bus as an auxiliary brake, and in particular, an eddy current reduction gear using permanent magnets (hereinafter, also simply referred to as "magnets") to generate a braking force. The present invention relates to a method of manufacturing (hereinafter, also simply referred to as "speed reduction gear").

  Many of the eddy current reducers marketed have a cylindrical braking member. The braking member is a rotor fixed to the rotation shaft of the vehicle. The magnets are arranged around the rotation axis inside the rotor and supported by the stator. At the time of braking, the magnetic flux from the magnet reaches the rotor and an eddy current is generated on the inner circumferential surface of the rotor. As a result, a braking torque is generated on the rotor that rotates integrally with the rotation shaft, and the rotation speed of the rotation shaft is gradually reduced.

  Switching between braking and non-braking is performed by an air cylinder. Here, strictly speaking, the magnet is held by a magnet holding ring which is concentric with the rotor. The magnet holding ring is supported by a stator fixed to the non-rotating part of the vehicle. The magnet holding ring is rotatable about the rotation axis. A lever projects from the side of the magnet holding ring. The piston rod of the air cylinder is connected to the lever via a link mechanism. The air cylinder is attached to the stator. Further, in the gap between the inner circumferential surface of the rotor and the magnet, the pole pieces are arranged around the rotation axis. The pole piece is supported by the stator. The operation of the air cylinder advances and retracts the piston rod and rotates the magnet holding ring. This switches the position of the magnet relative to the pole piece and switches between braking and non-braking.

  In order to improve the braking torque, a copper plating layer is formed on the inner peripheral surface of the rotor. This is because the eddy current generated on the inner circumferential surface of the rotor is increased. The braking torque is also improved by increasing the magnetic force of the magnet itself.

  The rotor generates heat as the braking torque is generated. Therefore, when the braking continues for a long time, the temperature of the rotor rises significantly. Excessive temperature rise of the rotor leads to thermal deformation of the rotor and must be avoided.

  In order to avoid excessive temperature rise of the rotor, the thickness of the rotor is increased. This is because the heat capacity of the rotor itself is increased, and the temperature rise of the rotor is suppressed even if the braking duration is long. In addition, excessive temperature rise of the rotor can be avoided by reducing the magnetic force of the magnet itself. While the braking torque can be suppressed, the heat generation of the rotor can be suppressed accordingly.

  Also, by changing the type of air cylinder, excessive temperature rise of the rotor can be avoided. For example, as an air cylinder, a two-stage air cylinder which can advance and retract the piston rod in two steps is adopted. By employing a two-stage air cylinder, the position of the magnet relative to the pole piece can be switched between the position at which the maximum braking torque is generated and the position at which approximately half the braking torque is generated. If necessary, by switching the position of the magnet relative to the pole piece to a position where a braking torque of about half the maximum braking torque is generated, the temperature rise of the rotor is suppressed even if the braking duration is long.

  The configuration of the above-described reduction gear is disclosed, for example, in International Publication WO 2014/126087 pamphlet (Patent Document 1), JP-A-9-172770 (Patent Document 2), and the like.

International Publication WO 2014/126087 Brochure Japanese Patent Application Laid-Open No. 9-172770

  Conventionally, in order to manufacture an order for a reduction gear, the reduction gear is designed as an exclusive product, taking into consideration many design parameters each time according to the required specifications (eg, braking torque, braking duration, etc.) Is going. As a result, not only can an excessive design burden be imposed each time an order is received, but also the time required for design increases, and an increase in cost can not be avoided.

  An object of the present invention is to provide a method of manufacturing an eddy current speed reducer which can greatly reduce design time and cost.

  The manufacturing method according to the embodiment of the present invention manufactures the following eddy current reduction gear. The reduction gear includes a rotor, a plurality of permanent magnets, a plurality of pole pieces, a magnet holding ring, a stator, and an air cylinder. The rotor is cylindrical and fixed to the rotational shaft. The magnets face the inner circumferential surface of the rotor with a gap, and are arranged around the rotation axis. The pole pieces are provided in the gap between the inner circumferential surface of the rotor and the magnet, and are arranged around the rotation axis. The magnet holding ring holds the magnet. The stator supports the magnet holding ring rotatably about the rotation axis and supports the pole piece. An air cylinder is attached to the stator and drives the magnet holding ring to switch the position of the magnet relative to the pole piece.

The method of manufacturing the reduction gear includes the following steps:
Setting a plurality of copper plating thicknesses according to the magnitude of the braking torque for the thickness of the copper plating layer formed on the inner peripheral surface of the rotor;
Setting a plurality of rotor thicknesses and cylinder types according to the length of the braking duration for the rotor thickness and the air cylinder type;
Selecting a combination of copper plating thickness, rotor thickness and cylinder type on the basis of the braking torque and the braking duration required for the reduction gear;
Preparing a rotor and an air cylinder that match the selected combination, and assembling a reduction gear.

  The above-described manufacturing method can adopt the following configuration. The plurality of copper plating thicknesses set are three types including zero. The plurality of rotor thicknesses to be set are two types. The plurality of cylinder types to be set are two types, a first-stage air cylinder and a two-stage air cylinder.

  According to the method of manufacturing a reduction gear of the present invention, the design time can be significantly shortened, and the manufacturing cost can be reduced.

FIG. 1 is a longitudinal sectional view schematically showing a reduction gear to be manufactured in the manufacturing method of the present embodiment. FIG. 2 is a perspective view showing the arrangement of magnets in the reduction gear shown in FIG. FIG. 3 is a cross-sectional view showing a magnetic circuit at the time of non-braking by the reduction gear shown in FIG. FIG. 4 is a cross-sectional view showing a magnetic circuit at the time of braking by the reduction gear shown in FIG. 1, and shows a state in which a maximum braking torque is generated. FIG. 5 is a cross-sectional view showing a magnetic circuit at the time of braking by the reduction gear shown in FIG. 1, and shows a state where a braking torque of about half the maximum braking torque is generated. FIG. 6 is a diagram summarizing the characteristics of the reduction gear manufactured by the manufacturing method of the present embodiment.

  Hereinafter, an embodiment of the method for manufacturing the eddy current reduction gear according to the present invention will be described in detail.

[Configuration of Eddy Current Type Reduction Gear]
FIG. 1 is a longitudinal sectional view schematically showing a reduction gear to be manufactured in the manufacturing method of the present embodiment. FIG. 2 is a perspective view showing the arrangement of magnets in the reduction gear shown in FIG. FIG. 3 is a cross-sectional view showing a magnetic circuit at the time of non-braking by the reduction gear shown in FIG. 4 and 5 are cross sectional views showing a magnetic circuit at the time of braking by the reduction gear shown in FIG. Of these figures, FIG. 4 shows a state in which the maximum braking torque is generated, and FIG. 5 shows a state in which a braking torque approximately half the maximum braking torque is generated. Among the states shown in FIGS. 3 to 5, the state shown in FIG. 5 appears when a two-stage air cylinder is used as an air cylinder for switching between braking and non-braking. Here, the longitudinal cross section is a cross section along the rotation axis. The cross section is a cross section orthogonal to the rotation axis.

  As shown in FIG. 1, the reduction gear includes a cylindrical rotor 1 and a cylindrical magnet holding ring 2 disposed inside the rotor 1. The rotor 1 corresponds to a braking member to which a braking torque is applied. The rotor 1 is fixed to a rotation shaft 10 (for example, a propeller shaft, a drive shaft, etc.) of a vehicle via a rotor support member 6. Thereby, the rotor 1 rotates integrally with the rotating shaft 10. A radiation fin 1 a is provided on the outer peripheral surface of the rotor 1. The heat dissipating fins 1a serve to cool the rotor 1 itself.

  The magnet holding ring 2 is paired with the rotor 1 and disposed concentrically with the rotor 1. The magnet holding ring 2 is rotatably supported around the rotation axis 10 via the stator 7. The stator 7 is fixed to a non-rotating portion 11 (for example, a transmission cover) of the vehicle.

  As shown in FIGS. 1 and 2, a plurality of permanent magnets 3 are fixed to the outer peripheral surface of the magnet holding ring 2. The magnets 3 are opposed to the inner circumferential surface 1 b of the rotor 1 with a gap, and are arranged in the circumferential direction around the rotation axis 10. That is, the magnets 3 are held by the magnet holding ring 2 and arranged around the rotation axis 10. The arrangement of the magnetic poles (N pole, S pole) of these magnets 3 in the radial direction centering on the rotation axis 10 is alternately different between magnets 3 adjacent in the circumferential direction (see FIG. 2). The material of the magnet holding ring 2 is a ferromagnetic material (eg, carbon steel, cast iron, etc.).

  As shown in FIGS. 1 and 3 to 5, a plurality of ferromagnetic pole pieces 4 are provided in the gap between the inner circumferential surface 1 b of the rotor 1 and the magnet 3. The pole pieces 4 are arranged circumferentially around the rotation axis 10. The arrangement angle of these pole pieces 4 matches the arrangement angle of the magnet 3. The pole pieces 4 are held by the pole piece holding ring 5 on both sides. The pole piece holding ring 5 is fixed to the stator 7. That is, the pole pieces 4 are supported by the stator 7 and arranged around the rotation axis 10.

  As shown in FIG. 1, the lever 2 a protrudes from the side surface of the magnet holding ring 2. A piston rod of an air cylinder (not shown) is connected to the lever 2a via a link mechanism (not shown). The air cylinder is attached to the stator 7. The air cylinder uses compressed air as a driving source and plays a role of switching between braking and non-braking. As the air cylinder, a one-stage air cylinder or a two-stage air cylinder is used. The one-stage air cylinder simply advances and retracts the piston rod in one step. The two-stage air cylinder is capable of advancing and retracting the piston rod in two stages. That is, in the two-stage air cylinder, advancing and retreating of the piston rod can be stopped halfway.

  At the time of switching between braking and non-braking, the piston rod is advanced and retracted by the operation of the air cylinder, and the magnet holding ring 2 and the magnet 3 integrally rotate around the rotating shaft 10. Thereby, the position of the magnet 3 with respect to the pole piece 4 takes the following states. At the time of non-braking, as shown in FIG. 3, the pole piece 4 straddles the adjacent magnets 3 equally. During braking, as shown in FIG. 4, the pole piece 4 completely overlaps the magnet 3. These states are common to the case where a one-stage air cylinder is adopted and the case where a two-stage air cylinder is adopted. In the braking state shown in FIG. 4, the maximum braking torque is generated. Hereinafter, this state is also referred to as "complete braking". Furthermore, at the time of braking in the case of employing a two-stage air cylinder, as shown in FIG. 5, the pole piece 4 widely overlaps one magnet 3 while unevenly straddling the magnets 3 adjacent to each other. In the braking state shown in FIG. 5, a braking torque that is about half the maximum braking torque is generated. Hereinafter, this state is also referred to as "suppression braking".

  Specifically, as shown in FIG. 3, the magnetic flux from the magnet 3 is in the following situation when braking is not performed. The magnetic flux emitted from the N pole of one of the magnets 3 adjacent to each other passes through the pole piece 4 and reaches the S pole of the other magnet 3. The magnetic flux emitted from the north pole of the other magnet 3 reaches the south pole of one magnet 3 through the magnet holding ring 2. That is, no magnetic circuit is generated between the magnet 3 and the rotor 1. In this case, no braking torque is generated on the rotor 1 that rotates integrally with the rotating shaft 10.

  At the time of full braking, the magnet holding ring 2 is rotated about half the arrangement angle of the magnet 3 from the non-braking state. Thereby, as shown in FIG. 4, the pole piece 4 completely overlaps the magnet 3. In this case, the magnetic flux from the magnet 3 is as follows.

  The magnetic flux emitted from the N pole of one of the magnets 3 adjacent to each other passes through the pole piece 4 and reaches the rotor 1. The magnetic flux reaching the rotor 1 reaches the south pole of the other magnet 3 through the pole piece 4. The magnetic flux emitted from the north pole of the other magnet 3 reaches the south pole of one magnet 3 through the magnet holding ring 2. That is, between the magnets 3 adjacent in the circumferential direction, the magnet holding ring 2, the pole piece 4, and the rotor 1, a magnetic circuit by the magnets 3 is formed. Such magnetic circuits are formed alternately in the opposite direction of the magnetic flux over the entire circumferential direction. In this case, the maximum braking torque in the direction opposite to the rotational direction is generated on the rotor 1 that rotates integrally with the rotating shaft 10.

  At the time of restraining braking, the magnet holding ring 2 is rotated by about 1⁄4 of the disposition angle of the magnet 3 from the non-braking state. As a result, as shown in FIG. 5, the pole piece 4 widely overlaps one magnet 3 while unevenly straddling the magnets 3 adjacent to each other. In this case, most of the magnetic circuit by the magnet 3 is the same as at full braking. However, part of the magnetic flux from the magnet 3 does not reach the rotor 1 as in the non-braking state. Therefore, the magnetic flux reaching the rotor 1 from the magnet 3 is smaller than that at the time of complete braking. Therefore, the braking torque generated during the restraining braking is approximately half of the maximum braking torque generated during the full braking.

  The material of the rotor 1 is a ferromagnetic material (eg, carbon steel, cast iron, etc.). A copper plating layer having high conductivity may be formed on the inner circumferential surface 1 b of the rotor 1. When the copper plating layer is formed on the inner peripheral surface 1 b of the rotor 1, the eddy current generated on the inner peripheral surface 1 b of the rotor 1 becomes large at the time of braking. Thereby, the braking torque can be improved.

[Method of Manufacturing Eddy Current Type Reduction Gear]
The method of manufacturing the reduction gear transmission according to the present embodiment includes a first setting step, a second setting step, a selection step, and an assembly step. In the first setting step, with respect to the thickness of the copper plating layer formed on the inner peripheral surface of the rotor, a plurality of copper plating thicknesses corresponding to the magnitude of the braking torque are set. The second setting step sets, for the thickness of the rotor and the type of the air cylinder, a plurality of rotor thicknesses and cylinder types according to the length of the braking duration. In the selection step, a combination of the copper plating thickness, the rotor thickness and the cylinder type set in the first setting step and the second setting step is selected based on the braking torque and the braking duration required of the reduction gear. The assembling process prepares the rotor and the air cylinder conforming to the combination selected in the selecting process, and assembles the reduction gear.

  In short, in the manufacturing method of the present embodiment, so-called modularization is introduced to manufacture the above-described reduction gear. That is, the reduction gear is divided into several modules, and the reduction gear is manufactured according to the required specifications. There are three modules: stator 7 (including magnet 3, magnet holding ring 2, pole piece 4 and pole piece holding ring 5), rotor 1 and air cylinder.

  FIG. 6 is a diagram summarizing the characteristics of the reduction gear manufactured by the manufacturing method of the present embodiment. In the present embodiment, as shown in FIG. 6, the reduction gear is classified into 12 models having different performances. These models 1 to 12 are divided into three ranks according to the magnitude of the braking torque (maximum braking torque). That is, four models 1 to 4 express low braking torque. Four of Model 5 to Model 8 exhibit moderate braking torque. Four of models 9 to 12 express high braking torque. Furthermore, four of Model 1 to Model 4, four of Model 5 to Model 8, and four of Model 9 to Model 12 are classified by the braking duration, respectively. For example, among the models 1 to 4, the braking duration of the model 1 is the shortest, and the braking duration of the model 4 is the longest. These models 1 to 12 are manufactured by combining a stator, a rotor and an air cylinder as modules according to the required specifications.

  The stator module is standardized to one type. That is, the configurations of the stator body, the magnet, the magnet holding ring, the pole piece, and the pole piece holding ring are common.

  The rotor module is standardized into 12 types corresponding to the models 1 to 12 by the thickness of the copper plating layer formed on the inner peripheral surface of the rotor and the thickness of the rotor. Here, the copper plating thickness is three types including zero. That is, the copper plating thickness is of three types: zero, thin and thick, in which the copper plating layer is not formed. The rotor thickness is a thickness in the radial direction of the rotor, and is of two types. That is, there are two types of rotor thickness: standard and thicker than standard.

  The air cylinder module is standardized into two types according to the type of air cylinder. There are two types of cylinders, one-stage cylinder and two-stage cylinder.

  Three types of copper plating thickness are set in the first setting step. The setting depends on the magnitude of the braking torque. For example, the braking torque by the rotor in which the copper plating layer is formed is higher than the braking torque by the rotor in which the copper plating layer is not formed. In addition, as the copper plating thickness increases, the braking torque increases, and the number of revolutions at which the peak torque is generated also moves to the low revolution range.

  The two types of rotor thickness and the two types of cylinder types are set in the second setting step. Their setting depends on the length of the braking duration. For example, as the thickness of the rotor increases, the heat capacity of the rotor itself increases. The greater the heat capacity of the rotor itself, the smaller the temperature rise of the rotor during braking. In short, as the rotor thickness is increased, the temperature rise of the rotor is suppressed, so that the braking duration can be extended. Further, when a two-stage cylinder is adopted, for example, it is possible to switch to restraining braking in which a braking torque of about half the maximum braking torque is generated. That is, when the two-stage cylinder is adopted, the temperature rise of the rotor is suppressed along with the switching to the suppression braking, so that the braking duration can be extended.

  Thus, in the first and second setting steps, the plurality of copper plating thicknesses, the rotor thickness and the cylinder type are respectively set. When the reduction gear is ordered, a combination of the copper plating thickness, the rotor thickness and the cylinder type set in the first and second setting steps is selected in the selection step. The choice is based on the braking torque and the braking duration required of the reduction gear. Thus, it is possible to select a rotor module and an air cylinder module that meet the required specifications.

  Then, in the assembly process, the rotor module and the air cylinder module that match the combination selected in the selection process are prepared, and the reduction gear is assembled. This makes it possible to manufacture a reduction gear that meets the required specifications.

  As described above, according to the manufacturing method of the present embodiment, the introduction of modularization does not impose an excessive design burden on each order received. Therefore, the design time can be significantly reduced, and the manufacturing cost can be reduced.

  Others The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the number of types of each of the copper plating thickness, the rotor thickness, and the cylinder type is not particularly limited as long as it is plural. However, if the number is too large, management becomes complicated. Therefore, the number set in the above embodiment is appropriate.

  The manufacturing method of the present invention is useful for manufacturing an eddy current reduction gear.

1: Rotor, 1a: Radiation fin, 1b: Inner circumferential surface of rotor,
2: Magnet holding ring, 2a: Lever, 3: Permanent magnet,
4: Pole piece, 5: Pole piece holding ring,
6: Rotor support member, 7: Stator,
10: rotation axis, 11: non-rotation part

Claims (2)

A manufacturing method of an eddy current type reduction gear, which
The reduction gear is
A cylindrical rotor fixed to the rotation shaft,
A plurality of permanent magnets which are opposed to the inner circumferential surface of the rotor with a gap and arranged around the rotation axis;
A plurality of pole pieces provided in the gap and arranged around the rotation axis;
A magnet holding ring for holding the permanent magnet;
A stator which supports the magnet holding ring rotatably about the rotation axis and supports the pole piece;
An air cylinder attached to the stator and driving the magnet holding ring to switch the position of the permanent magnet relative to the pole piece;
The manufacturing method is
Setting a plurality of copper plating thicknesses according to the magnitude of the braking torque for the thickness of the copper plating layer formed on the inner peripheral surface of the rotor;
Setting a plurality of rotor thicknesses and cylinder types according to the length of the braking duration for the thickness of the rotor and the type of the air cylinder;
Selecting a combination of the copper plating thickness, the rotor thickness, and the cylinder type based on a braking torque and a braking duration required for the reduction gear;
Preparing a rotor and an air cylinder suitable for the selected combination, and assembling the reduction gear. The method of manufacturing an eddy current reduction gear according to claim 1,
There are three types of copper plating thickness set, including zero.
There are two types of rotor thickness to be set,
The manufacturing method of the eddy current reduction gear according to the present invention, wherein the plurality of cylinder types to be set are two types of one-stage air cylinder and two-stage air cylinder.

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