JP2018152998A - Motor and method of assembling pinion shaft - Google Patents

Abstract

The present invention relates to a motor in which a pinion shaft is assembled to a motor shaft, and provides a technique useful for improving productivity. A motor shaft 32 having a recess 32b at a load side end, a pinion shaft 34 pushed into the recess 32b, a load side bearing 36 and an anti-load side bearing 38 that support the motor shaft 32 are provided. The load transmission member 12 is configured to transmit the thrust load Fa acting on the motor shaft 32 toward the non-load side to the load receiving member 64 other than the load-side bearing 36 and the anti-load-side bearing 38. A structure 40 is provided. [Selection] Figure 2

Description

  The present invention relates to a motor and a method for assembling a pinion shaft.

  In some cases, a pinion shaft is assembled to the motor shaft so that the rotational power can be transmitted to the speed reducer or the driven device. As an example of this, Patent Document 1 discloses a motor in which a recess is provided in a motor shaft, and a pinion shaft is pushed into the recess by shrink fitting.

Japanese Patent Laid-Open No. 2006-63599

  When shrink fitting is used for assembling the pinion shaft as in the motor of Patent Document 1, it is necessary to heat the concave portion of the motor shaft. Along with this, the time required for assembling the pinion shaft increases excessively, so there is room for improvement from the viewpoint of productivity.

  An aspect of the present invention has been made in view of such circumstances, and one of its purposes is to provide a technique that helps improve productivity with respect to a motor in which a pinion shaft is assembled to a motor shaft.

  One embodiment of the present invention relates to a motor. The motor includes a motor shaft having a recess at a load side end, a pinion shaft pushed into the recess, and a load side bearing and an anti-load side bearing that support the motor shaft. A load transmission structure is provided for allowing a thrust load acting on the motor shaft toward the anti-load side to be transmitted to a load receiving member other than the load-side bearing and the anti-load side bearing.

  Another aspect of the invention relates to a motor. The motor includes a motor shaft having a recess at a load side end, and a pinion shaft pushed into the recess, and the pinion shaft is for inserting a bolt from the load side. An insertion hole is formed, and a tapped hole for screwing the bolt is formed at the bottom of the recess.

  Another aspect of the present invention relates to a method for assembling a pinion shaft. This method is a method for assembling a pinion shaft to a motor shaft of a motor, wherein the motor shaft has a recess at a load side end portion, and the motor has a load side bearing and a reaction member supporting the motor shaft. A load-side bearing and a load transmission structure for transmitting a thrust load acting on the motor shaft toward the anti-load side to a load receiving member other than the load-side bearing and the anti-load-side bearing. And the pinion shaft is press-fitted into the recess in a state where the thrust load can be transmitted from the motor shaft to the load receiving member using the load transmission structure.

  Another aspect of the present invention relates to a method for assembling a pinion shaft. This method is a method for assembling a pinion shaft to a motor shaft of a motor, and the motor shaft has a recess at a load side end, and a bolt is inserted into the pinion shaft from the load side. An insertion hole is formed, a tapped hole is formed at the bottom of the recess, and a bolt inserted into the insertion hole is screwed into the tapped hole, thereby applying a pressure input from the bolt to the pinion shaft, The pinion shaft is press-fitted into the recess.

  ADVANTAGE OF THE INVENTION According to this invention, the technique useful for improvement of productivity can be provided regarding the motor by which the pinion shaft was assembled | attached to the motor shaft.

It is sectional drawing which shows the gear motor in which the motor of 1st Embodiment is used. It is a figure which shows the assembly | attachment process of the pinion shaft of 1st Embodiment. It is a figure which shows the assembly | attachment process of the pinion shaft using the motor of 2nd Embodiment. It is a figure which shows the assembly | attachment process of the pinion shaft using the motor of 3rd Embodiment. It is a figure which shows the assembly | attachment process of the pinion shaft using the motor of 4th Embodiment. It is a figure which shows the assembly | attachment process of the pinion shaft using the motor of 5th Embodiment. FIG. 7 is an enlarged view around the pinion axis of FIG. 6. FIG. 8A is a diagram illustrating an intermediate state of the pinion shaft assembly process of the fifth embodiment, and FIG. 8B is another diagram illustrating an intermediate state of the pinion shaft assembly process of the fifth embodiment. FIG.

  Hereinafter, in the embodiment and the modification, the same reference numerals are given to the same components, and the duplicate description is omitted. In the drawings, for convenience of explanation, some of the components are omitted as appropriate, and the dimensions of the components are appropriately enlarged and reduced.

(First embodiment)
First, the background that led to the idea of the motor of the first embodiment will be described. With respect to a motor in which the pinion shaft is assembled to the motor shaft, press fitting may be used for assembling the pinion shaft in order to improve productivity. When the pinion shaft is press-fitted into the motor shaft, a thrust load from the pinion shaft toward the non-load side acts on the motor shaft. This thrust load is normally received by a non-load side bearing that supports the motor shaft. Therefore, when the thrust load acting on the motor shaft increases, there is a concern about the burden on the non-load side bearing. In particular, when press fitting is used for assembling the pinion shaft, the thrust load acting on the motor shaft is increased as compared with the case where shrink fitting is used.

  As a countermeasure against this, the motor according to the present embodiment includes a load transmission structure that enables transmission of a thrust load acting on the motor shaft toward the anti-load side to the load receiving member. As a result, the pinion shaft can be press-fitted into the recess of the motor shaft in a state in which the thrust load can be transmitted from the motor shaft to the load receiving member using the load transmission structure, and the load on the non-load side bearing at the time of the press-fitting can be reduced. It can be suppressed. Therefore, according to the motor of the present embodiment, the pinion shaft can be press-fitted into the recess of the motor shaft while suppressing the load on the anti-load side bearing, which can be used to improve the productivity of the motor. Details of the motor according to the first embodiment will be described below.

  FIG. 1 is a cross-sectional view showing a gear motor 10 in which the motor 12 of the first embodiment is used. The gear motor 10 includes a motor 12 and a speed reducer 14, which are integrated. In this specification, the axial direction, circumferential direction, and radial direction of the motor shaft 32 of the motor 12 are also simply referred to as “axial direction”, “circumferential direction”, and “radial direction”. Of the axial direction of the motor shaft 32, on the power transmission path passing through the motor shaft 32, the side close to the driven device is referred to as the load side, and the side opposite to the load side is referred to as the anti-load side. The speed reducer 14 will be described first.

  The speed reducer 14 includes a speed reducer casing 16, an output member 18, and a speed reduction mechanism 20. The speed reducer casing 16 includes a cylindrical casing body 22 in which the speed reduction mechanism 20 is housed, and an anti-load side wall portion 24 that is disposed on the side opposite to the load from the speed reduction mechanism 20. The casing main body portion 22 of the present embodiment has a first main body member 22a disposed on the anti-load side and a second main body member 22b disposed on the load side.

  The output member 18 is for outputting the rotational power of the motor shaft 32 to the driven device. The output member 18 is housed inside the casing body 22 and is rotatably supported by the casing body 22 via a bearing (not shown).

  The speed reduction mechanism 20 can reduce the rotational power of the motor shaft 32 and transmit it to the output member 18. The speed reduction mechanism 20 of the present embodiment is a distributed eccentric rocking speed reduction mechanism. Since this type of speed reduction mechanism 20 is well known, the description will be simplified here.

  The speed reduction mechanism 20 has a plurality of input gears 26 arranged around a pinion shaft 34 described later. In the figure, only one input gear 26 is shown. The input gear 26 meshes with the pinion portion 34 b of the pinion shaft 34. The input gear 26 is supported by a crankshaft 28 inserted through the central portion thereof, and is provided so as to be rotatable together with the crankshaft 28. When the input gear 26 rotates due to the rotation of the pinion shaft 34, the rotation of the pinion shaft 34 is decelerated and transmitted from the speed reduction mechanism 20 to the output member 18.

  Turning to the description of the motor 12. The motor 12 of this embodiment is a servo motor. The motor 12 mainly includes a motor casing 30, a motor shaft 32, a pinion shaft 34, a load side bearing 36, an anti-load side bearing 38, and a load transmission structure 40.

  The motor casing 30 includes a motor frame 42, a load side cover 44, a first anti-load side cover 46, and a second anti-load side cover 48.

  The motor frame 42 has a cylindrical shape, and the stator 50 and the rotor 52 are accommodated inside thereof. The stator 50 can generate a rotating magnetic field for rotating the rotor 52 and is fixed to the motor frame 42. The rotor 52 can be rotated by a magnetic interaction with a rotating magnetic field generated by the stator 50. The motor shaft 32 is provided so as to be able to rotate integrally with the rotor 52.

  The load side cover 44 covers the load side opening of the motor frame 42 and is fixed to the motor frame 42 with bolts. The load side cover 44 of this embodiment also serves as the anti-load side wall portion 24 of the reduction gear casing 16. However, the load side cover 44 may be provided separately from the anti-load side wall portion 24 without using the anti-load side wall portion 24 of the reduction gear casing 16. The load side cover 44 separates the internal space 30a of the motor casing 30 from the other space 54 provided on the load side from the internal space 30a. The other space 54 in this embodiment is an internal space of the reduction gear casing 16.

  The load side cover 44 is formed with a first through hole 44a that penetrates the load side cover 44 in the axial direction and through which the motor shaft 32 is inserted. An oil seal 56 is interposed between the motor shaft 32 and the first through hole 44a. The oil seal 56 regulates leakage of the lubricating oil sealed in the reduction gear casing 16. The oil seal 56 is provided on the side opposite to the load from the opening end edge 44b on the load side of the first through hole 44a.

  In the load side cover 44, a first fitting portion 44c is formed on the opposite side of the first through hole 44a. The load side bearing 36 is fitted into the first fitting portion 44c by gap fitting, and the load side cover 44 supports the load side bearing 36 in the first fitting portion 44c. Note that the load-side bearing 36 may be fitted into the first fitting portion 44c by interference fitting.

  The first anti-load side cover 46 covers the anti-load side opening of the motor frame 42 and is fixed to the motor frame 42 with bolts. The first anti-load side cover 46 separates the internal space 30a of the motor casing 30 from other spaces 48a and 58 provided on the anti-load side from the internal space 30a. The other spaces 48 a and 58 in the present embodiment are a cover inner space 48 a inside the second anti-load side cover 48 and an outer space 58 outside the motor casing 30.

  The first anti-load side cover 46 is formed with a second through hole 46a that passes through the first anti-load side cover 46 in the axial direction and through which the motor shaft 32 is inserted. In the first anti-load side cover 46, a second fitting portion 46b is formed at the load side portion of the second through hole 46a. An anti-load side bearing 38 is fitted into the second fitting portion 46b by a clearance fit, and the first anti-load side cover 46 supports the anti-load side bearing 38 in the second fitting portion 46b. Note that the anti-load side bearing 38 may be fitted into the second fitting portion 46b by interference fitting.

  The second anti-load side cover 48 is disposed closer to the anti-load side than the first anti-load side cover 46. The second anti-load side cover 48 includes a cover portion 48a having a bottomed cylindrical shape, and a flange portion 48b projecting radially outward from the opening edge of the cover portion 48a. The flange portion 48 b is abutted against the anti-load side wall surface of the first anti-load side cover 46, and is detachably attached to the first anti-load side cover 46 using an attachment bolt 60.

  The load side end portion 32 a of the motor shaft 32 protrudes from the load side cover 44 to the load side. The motor shaft 32 has a recess 32b formed in the load side end 32a. The recess 32b is formed so as to be recessed from the load side end surface of the motor shaft 32 to the non-load side.

  The anti-load side end 32c of the motor shaft 32 protrudes from the first anti-load side cover 46 to the anti-load side. The anti-load side end portion 32 c of the motor shaft 32 is covered from the anti-load side and the radially outer side by the cover portion 48 a of the second anti-load side cover 48.

  A rotation angle detection device 62 is disposed around the opposite end 32c of the motor shaft 32. The rotation angle detection device 62 is for detecting the rotation angle of the motor shaft 32 and is, for example, a rotary encoder. A detection signal of the rotation angle detection device 62 is output to an external control device (not shown) and used for controlling the motor 12 by the external control device. The rotation angle detection device 62 includes a housing 62a that houses detection elements such as a light emitting element and a light receiving element. A part of the non-load side end 32c of the motor shaft 32 protrudes from the housing 62a to the non-load side. The rotation angle detection device 62 is covered from the anti-load side or the radially outer side by the cover portion 48 a of the second anti-load side cover 48.

  A fan for cooling the motor casing 30 is not attached to the opposite end 32c of the motor shaft 32. This fan is provided so as to be able to rotate integrally with the motor shaft 32, and generates an air flow for cooling the motor casing 30 by the rotation.

  The pinion shaft 34 is provided coaxially with the motor shaft 32. The pinion shaft 34 includes a shaft portion 34a that is pushed into the recess 32b of the motor shaft 32, and a pinion portion 34b that is provided on the load side from the shaft portion 34a. The shaft portion 34 a is fitted into the recess 32 b of the motor shaft 32 by an interference fit, and can rotate integrally with the motor shaft 32. A plurality of teeth that mesh with the input gear 26 are formed on the outer peripheral surface of the pinion portion 34b. The rotational power of the motor shaft 32 is transmitted to the input gear 26 through the pinion shaft 34 by the engagement of the input gear 26 and the pinion portion 34b.

  The load side bearing 36 rotatably supports a load side portion on the load side of the rotor 52 of the motor shaft 32. The load side bearing 36 is, for example, a rolling bearing. The inner ring of the load side bearing 36 is fixed to the load side portion of the motor shaft 32 by an interference fit.

  The anti-load side bearing 38 rotatably supports an anti-load side portion on the anti-load side from the rotor 52 of the motor shaft 32. The anti-load side bearing 38 is, for example, a rolling bearing. The inner ring of the load side bearing 36 is fixed to the non-load side portion of the motor shaft 32 by an interference fit.

  FIG. 2 is a diagram illustrating an assembly process of the pinion shaft 34. The load transmitting structure 40 is for enabling the thrust load Fa acting on the motor shaft 32 to be transmitted to the load receiving member 64 other than the load side bearing 36 and the anti-load side bearing 38. This thrust load Fa acts on the motor shaft 32 toward the non-load side when the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32.

  The load transmitting structure 40 according to the present embodiment is a counter-load side end surface 32 d of the motor shaft 32. When the second anti-load side cover 48 is not provided, the anti-load side end surface 32d of the motor shaft 32 is exposed to the external space 58 on the anti-load side from the first anti-load side cover 46. In this embodiment, “when the second anti-load side cover 48 is not present” means when the second anti-load side cover 48 is in a stage before being attached to the first anti-load side cover 46.

  The load receiving member 64 is disposed in the external space 58 on the anti-load side from the first anti-load side cover 46. The load receiving member 64 is a transmission destination of the thrust load Fa acting on the motor shaft 32. The load receiving member 64 is provided with a receiving surface 64 a for receiving the thrust load Fa of the motor shaft 32. The receiving surface 64a of this embodiment is a flat surface. The receiving surface 64a of the load receiving member 64 is in direct contact with the non-load-side end surface 32d of the motor shaft 32. As a result, the thrust load Fa of the motor shaft 32 can be transmitted from the motor shaft 32 to the load receiving member 64.

  A method for assembling the pinion shaft 34 using the motor 12 will be described. First, the component parts of the motor 12 are assembled to the motor casing 30, and a semi-finished product 66 in which the pinion shaft 34 is not assembled to the motor shaft 32 is prepared. The components to be assembled here include the motor shaft 32, the load-side bearing 36, the anti-load-side bearing 38, the stator 50, the rotor 52, the rotation angle detection device 62, and the like, and the second anti-load-side cover 48. Is not included.

  In addition, the 1st main body member 22a of the reduction gear casing 16 is assembled | attached to the semifinished product 66 of this embodiment, and other components (deceleration mechanism 20 grade | etc.,) Of the reduction gear 14 are not assembled | attached. Thereby, the space which can arrange | position a press metal mold | die inside the 1st main body member 22a is ensured.

  Subsequently, the load transmitting structure 40 is used to make the thrust load Fa of the motor shaft 32 transmittable from the motor shaft 32 to the load receiving member 64 (hereinafter referred to as a load transmittable state). In the present embodiment, the semi-finished product 66 of the motor 12 is brought into a load-transmittable state by bringing the anti-load side end surface 32d of the motor shaft 32 serving as the load transmitting structure 40 into contact with the receiving surface 64a of the load receiving member 64. .

  Subsequently, while the semi-finished product 66 of the motor 12 is in a state capable of transmitting a load, the shaft portion 34a of the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32 toward the non-load side. In this press-fitting process, press input is applied to the pinion shaft 34 using a press die or the like. This press-fitting process is performed in a state where the semi-finished product 66 and the load receiving member 64 of the motor 12 are fixed by a jig or the like. This press-fitting process is performed in a room temperature environment without heating the motor shaft 32 and the pinion shaft 34. The pinion shaft 34 is press-fitted into the recess 32b until it contacts the bottom surface of the recess 32b of the motor shaft 32. Note that the press-fit of the pinion shaft 34 may be stopped before it hits the bottom surface of the recess 32b of the motor shaft 32. After the pinion shaft 34 is press-fitted into the recess 32 b of the motor shaft 32, the second anti-load side cover 48 is attached to the first anti-load side cover 46.

  Thereby, when the pinion shaft 34 is press-fitted into the recess 32 b of the motor shaft 32, the thrust load Fa acting on the motor shaft 32 is transmitted to the load receiving member 64, and the burden on the anti-load side bearing 38 can be suppressed. In the present embodiment, the thrust load Fa is transmitted to the load receiving member 64 from the non-load side end surface 32d of the motor shaft 32. That is, the thrust load Fa is transmitted from the load transmission structure 40 of the motor shaft 32 to the load receiving member 64.

  In the present embodiment, since the load transmitting structure 40 is the anti-load side end face 32d of the motor shaft 32, when the pinion shaft 34 is assembled, it is not necessary to attach or detach other members to the motor shaft 32. In addition, since the motor 12 includes the second anti-load side cover 48 that covers the anti-load side end surface 32d of the motor shaft 32, the motor shaft 32 can be protected from contact with an external object and safety can be ensured.

  Note that an example has been described in which the anti-load side end surface 32d of the motor shaft 32 serving as the load transmission structure 40 protrudes from the first anti-load side cover 46 to the anti-load side. In addition, when the anti-load side end surface 32 d of the motor shaft 32 is exposed to the external space 58, the anti-load side end surface 32 d may not protrude from the first anti-load side cover 46 to the anti-load side. In this case, for example, the load receiving member 64 is provided with a protrusion that protrudes toward the load side and can be inserted into the second through hole 46a of the first anti-load side cover 46, and the receiving surface 64a is provided at the tip of the protrusion. It may be provided. Also by this, the above-described load transmission possible state can be achieved.

(Second Embodiment)
FIG. 3 is a diagram illustrating an assembly process of the pinion shaft 34 using the motor 12 of the second embodiment. The motor 12 of the second embodiment is mainly different from the first embodiment in the load transmission structure 40. The load transmitting structure 40 of the second embodiment is a female screw hole 32e formed in the counter-load side end surface 32d of the motor shaft 32. The female screw hole 32e functions as a mounting portion for detachably mounting a screw member 68 described later.

  A screw member 68 is mounted in the female screw hole 32 e of the motor shaft 32. The screw member 68 functions as a load transmission member 70 for transmitting the thrust load of the motor shaft 32 from the motor shaft 32 to the load receiving member 64. The screw member 68 also functions as a protruding member that protrudes from the anti-load side end surface 32d of the motor shaft 32 to the anti-load side. The screw member 68 is attached to the motor shaft 32 only during the assembly process of the pinion shaft 34, and is removed from the motor shaft 32 after the motor 12 is assembled.

  The screw member 68 has a screw shaft portion 68a in which a male screw portion is formed, and a head portion 68b provided on the proximal end side of the screw shaft portion 68a. The screw member 68 is mounted by screwing the screw shaft portion 68a into the female screw hole 32e of the motor shaft 32. A head surface 68 b of the screw member 68 is formed with a contact surface 70 a for contacting the receiving surface 64 a of the load receiving member 64. The contact surface 70a of the present embodiment is a flat surface. When the second anti-load side cover 48 is not provided, the screw member 68 is exposed to the external space 58 on the anti-load side from the first anti-load side cover 46.

  A method for assembling the pinion shaft 34 using the motor 12 will be described. First, as in the first embodiment, a semi-finished product 66 in which the pinion shaft 34 is not assembled to the motor shaft 32 is prepared.

  Subsequently, the screw member 68 is attached to the female screw hole 32 e of the motor shaft 32 to be the load transmitting structure 40, and the contact surface 70 a of the screw member 68 is brought into contact with the receiving surface 64 a of the load receiving member 64. As a result, a load transmitting state is established in which the thrust load Fa of the motor shaft 32 can be transmitted from the motor shaft 32 to the load receiving member 64 using the female screw hole 32e serving as the load transmitting structure 40.

  Subsequently, while the semi-finished product 66 of the motor 12 is in a state capable of transmitting a load, the shaft portion 34a of the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32 toward the non-load side. Thereafter, the screw member 68 is removed from the female screw hole 32 e of the motor shaft 32, and the second anti-load side cover 48 is attached to the first anti-load side cover 46.

  Thereby, when the pinion shaft 34 is press-fitted into the recess 32 b of the motor shaft 32, the thrust load Fa acting on the motor shaft 32 is transmitted to the load receiving member 64, and the burden on the anti-load side bearing 38 can be suppressed. In the present embodiment, the thrust load Fa is transmitted from the female screw hole 32 e of the motor shaft 32 to the load receiving member 64 through the screw member 68. That is, the thrust load Fa is transmitted from the load transmission structure 40 of the motor shaft 32 to the load receiving member 64 via the load transmission member 70.

  In the present embodiment, the screw member 68 is attached to the anti-load side end surface 32d of the motor shaft 32, so that the load receiving member 64 is applied to a position separated from the anti-load side end surface 32d of the motor shaft 32 to the anti-load side. A contact surface 70a for contacting can be arranged. Therefore, by adjusting the axial dimension of the screw member 68 regardless of the projecting dimension of the motor shaft 32 from the first anti-load side cover 46, the semi-finished product 66 of the motor 12 can be easily transmitted. For this reason, when the semi-finished product 66 of the motor 12 is made in a state capable of transmitting a load, a design in which the projecting dimension of the motor shaft 32 is reduced or a design in which the motor shaft 32 is not projected from the first anti-load side cover 46 is allowed. .

  In the present embodiment, an example in which the protruding member that protrudes from the anti-load side end face 32d of the motor shaft 32 to the anti-load side is the screw member 68, and the mounting portion to which the protruding member is mounted is the female screw hole 32e. did. The combination of the projecting member and the mounting portion is not limited to the combination of the screw member 68 and the female screw hole 32e. For example, the mounting portion may be a recess provided on the non-load-side end surface 32d of the motor shaft 32, and the protruding member may be a columnar body that is partially pushed into the recess and extends coaxially with the motor shaft 32. Further, as in the present embodiment, when the load transmission structure 40 is a mounting portion, a fan may be mounted on the non-load side end portion 32c of the motor shaft 32.

(Third embodiment)
FIG. 4 is a diagram illustrating an assembly process of the pinion shaft 34 using the motor 12 of the third embodiment. An example in which the load receiving member 64 of the first embodiment and the second embodiment is a member different from the motor 12 has been described. The load receiving member 64 of this embodiment is the load side cover 44 of the motor 12. On the load side wall surface of the load side cover 44, a receiving surface 64a for receiving the thrust load Fa of the motor shaft 32 is provided. The receiving surface 64a of this embodiment is provided at the opening peripheral edge of the first through hole 44a on the load side. The receiving surface 64 a of the present embodiment is a flat surface and has an annular shape that is concentric with the motor shaft 32.

  In the second embodiment, the female screw hole 32e (mounting portion) formed in the anti-load side end surface 32d of the motor shaft 32 is the load transmitting structure 40, and the screw member 68 mounted in the female screw hole 32e is the load transmitting member. An example of 70 has been described.

  The load transmission structure 40 of the present embodiment is a through hole 32 f formed in the load side portion of the motor shaft 32. The through hole 32f functions as a holding portion for holding a contact member 72 described later in a detachable manner. The through hole 32 f is provided in the vicinity of the receiving surface 64 a of the load side cover 44. More specifically, the through hole 32 f is provided at a position that overlaps or substantially overlaps the receiving surface 64 a of the load side cover 44 in the axial direction. Further, the through hole 32 f is provided on the side opposite to the load from the recess 32 b of the motor shaft 32. The through hole 32 f extends linearly along a direction orthogonal to the axial direction of the motor shaft 32.

  The load transmission member 70 of the present embodiment is a contact member 72 that is held in the through hole 32f by being inserted into the through hole 32f of the motor shaft 32. Thereby, the position of the contact member 72 in the axial direction with respect to the motor shaft 32 is maintained. The contact member 72 is held by the motor shaft 32 only during the assembly process of the pinion shaft 34, and is removed from the motor shaft 32 after the motor 12 is assembled.

  The contact member 72 of this embodiment is a long body, and is inserted into the through hole 32f of the motor shaft 32 so as to be removable in the longitudinal direction of the contact member 72 (left and right direction in the figure). The contact member 72 and the through hole 32f have a cross-sectional shape that fits together. In the present embodiment, the contact member 72 has a prismatic cross-sectional shape, and the through hole 32 f has a square hole-shaped cross-sectional shape that fits with the contact member 72.

  The contact member 72 has a contact surface 70 a that contacts the receiving surface 64 a of the load side cover 44. The contact surface 70a of the present embodiment is a flat surface facing the anti-load side, and is provided at both ends of the contact member 72 in the longitudinal direction. The contact surface 70a of the contact member 72 contacts the receiving surface 64a of the load side cover 44 in a state of surface contact. The load-side inner wall surface of the through hole 32f of the motor shaft 32 is also in contact with the load-side outer wall surface of the contact member 72 in a state of surface contact.

  A method for assembling the pinion shaft 34 using the motor 12 will be described. First, as in the first embodiment, a semi-finished product 66 in which the pinion shaft 34 is not assembled to the motor shaft 32 is prepared. At this time, unlike the first embodiment and the second embodiment, the second anti-load side cover 48 may be assembled to the semi-finished product 66 of the motor 12.

  Subsequently, the contact member 72 is inserted into the through hole 32f of the motor shaft 32 to be the load transmitting structure 40, the contact member 72 is held in the through hole 32f of the motor shaft 32, and the contact surface of the contact member 72 70 a is brought into contact with the receiving surface 64 a of the load side cover 44. As a result, the load transmitting structure 40 can be used to transmit the thrust load Fa of the motor shaft 32 from the motor shaft 32 to the load side cover 44.

  Subsequently, while the semi-finished product 66 of the motor 12 is in a state capable of transmitting a load, the shaft portion 34a of the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32 toward the non-load side. Thereafter, the contact member 72 is extracted from the through hole 32 f of the motor shaft 32.

  Thus, when the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32, the thrust load Fa acting on the motor shaft 32 is transmitted to the load side cover 44, and the burden on the anti-load side bearing 38 can be suppressed. In the present embodiment, the thrust load Fa is transmitted from the through hole 32 f of the motor shaft 32 to the load side cover 44 via the contact member 72. That is, the thrust load Fa is transmitted from the load transmission structure 40 of the motor shaft 32 to the load side cover 44 via the load transmission member 70.

(Fourth embodiment)
FIG. 5 is a diagram illustrating an assembly process of the pinion shaft 34 using the motor 12 of the fourth embodiment. In the third embodiment, the example in which the through hole 32f formed in the load side portion of the motor shaft 32 is the load transmitting structure 40 has been described.

  In the present embodiment, the groove portion 32 g formed in the load side portion of the motor shaft 32 is the load transmission structure 40. The groove 32g is formed in the outer peripheral surface of the load side portion of the motor shaft 32 along the circumferential direction. The groove portion 32g functions as a holding portion for detachably holding a contact member 72 described later.

  The contact member 72 according to the present embodiment is fitted between the retaining ring 72a held in the groove 32g by being fitted into the groove 32g serving as the load transmitting structure 40, and between the receiving surface 64a of the load side cover 44 and the retaining ring 72a. And a ring member 72b sandwiched between the two. The retaining ring 72a has an annular shape with a part cut away, and can be expanded in the radial direction. The load side portion of the motor shaft 32 is inserted inside the ring member 72b. The contact member 72 has a retaining ring 72a fitted in the groove portion 32g of the motor shaft 32, and the ring member 72b is sandwiched between the load side cover 44 and the retaining ring 72a, so that the groove portion 32g of the motor shaft 32 is engaged. Retained. At this time, the position of the contact member 72 in the axial direction with respect to the motor shaft 32 is maintained.

  A method for assembling the pinion shaft 34 using the motor 12 will be described. First, as in the third embodiment, a semi-finished product 66 in which the pinion shaft 34 is not assembled to the motor shaft 32 is prepared.

  Subsequently, the load side portion of the motor shaft 32 is inserted inside the ring member 72b of the contact member 72, and the ring member 72b is moved to the anti-load side until it contacts the receiving surface 64a of the load side cover 44. . Thereafter, the retaining ring 72a of the contact member 72 is fitted into the groove 32g of the motor shaft 32, and the position of the retaining ring 72a and the ring member 72b with respect to the motor shaft 32, that is, the contact member 72 in the axial direction is held. As a result, the load 32 can be transmitted so that the thrust load Fa of the motor shaft 32 can be transmitted from the motor shaft 32 to the load-side cover 44 by using the groove portion 32 g serving as the load transmission structure 40.

  Subsequently, while the semi-finished product 66 of the motor 12 is in a state capable of transmitting a load, the shaft portion 34a of the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32 toward the non-load side. Thereafter, the diameter of the retaining ring 72 a of the contact member 72 is expanded and removed from the groove 32 g of the motor shaft 32, and then the ring member 72 b of the contact member 72 is also removed from the motor shaft 32.

  Thus, when the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32, the thrust load Fa acting on the motor shaft 32 is transmitted to the load side cover 44, and the burden on the anti-load side bearing 38 can be suppressed. In the present embodiment, a thrust load is transmitted from the groove 32 g of the motor shaft 32 to the load side cover 44 via the contact member 72. That is, the thrust load Fa is transmitted from the load transmission structure 40 of the motor shaft 32 to the load side cover 44 via the load transmission member 70.

  In the third embodiment, the holding portion that holds the contact member 72 that contacts the load side cover 44 is the through hole 32f, and in the fourth embodiment, the holding portion is the groove portion 32g. This holding part is not limited to these. Further, in the contact member 72 of the fourth embodiment, the first member fitted into the groove portion 32g serving as the holding portion is a retaining ring 72a, and is sandwiched between the receiving surface 64a of the load side cover 44 and the retaining ring 72a. The example in which the second member is the ring member 72b has been described. The combination of the first member and the second member is not limited to the retaining ring 72a and the ring member 72b. For example, the first member may be a long body inserted through a through hole formed as a holding portion in the motor shaft 32. Alternatively, a male screw portion may be formed as a holding portion on the motor shaft 32, and a nut body as the contact member 72 may be attached to the male screw portion.

(Fifth embodiment)
FIG. 6 is a diagram illustrating an assembly process of the pinion shaft 34 using the motor 12 of the fifth embodiment. In the above-described embodiment, the example in which the load transmission structure 40 is provided in the motor 12 has been described in order to suppress the burden on the anti-load side bearing 38 when the pinion shaft 34 is press-fitted. In the present embodiment, for the same purpose, the following configuration is adopted instead of providing the motor 12 with the load transmitting structure 40.

  FIG. 7 is an enlarged view around the pinion axis 34 of FIG. The pinion shaft 34 is formed with an insertion hole 34c for inserting the press-fit bolt 74 from the load side. The press-fit bolt 74 is used for press-fitting the pinion shaft 34 into the recess 32b of the motor shaft 32, as will be described later. The insertion hole 34 c is formed along the axial direction of the motor shaft 32. The insertion hole 34c penetrates the pinion shaft 34 in the axial direction and opens toward both sides in the axial direction. The insertion hole 34c is a drill hole that allows insertion / removal in the axial direction without rotation of the press-fitting bolt 74. A tapped hole 32h for screwing the press-fit bolt 74 is formed at the bottom of the recess 32b of the motor shaft 32. The tap hole 32h is formed so as to be recessed from the bottom surface of the recess 32b toward the anti-load side, and opens toward the load side.

  A method for assembling the pinion shaft 34 using the motor 12 will be described. First, as in the first embodiment, a semi-finished product 66 in which the pinion shaft 34 is not assembled to the motor shaft 32 is prepared.

  Subsequently, the press-fitting bolt 74 is inserted into the insertion hole 34c of the pinion shaft 34 from the load side, and a part of the screw shaft portion 74a of the press-fitting bolt 74 is protruded from the insertion hole 34c toward the opposite load side. In this state, as shown in FIG. 8A, the screw shaft portion 74a of the press-fitting bolt 74 is inserted into the recess 32b of the motor shaft 32, and the screw shaft portion 74a is screwed into the tap hole 32h of the motor shaft 32. . Here, the screw shaft portion 74a of the press-fit bolt 74 has a projecting dimension Lb from the insertion hole 34c of the pinion shaft 34 larger than the dimension La in the axial direction from the load side opening of the recess 32b of the motor shaft 32 to the bottom surface. Is set to be This eliminates the need to press-fit the shaft portion 34a of the pinion shaft 34 into the recess 32b of the motor shaft 32 until the screw shaft portion 74a of the press-fit bolt 74 is screwed into the tap hole 32h of the motor shaft 32.

  Thereafter, as shown in FIG. 8B, a rotational force Fc in the screwing direction is applied to the press-fit bolt 74, and the screw shaft portion 74a of the press-fit bolt 74 is screwed into the tap hole 32h by the rotational force Fc. When the rotational force Fc in the screw tightening direction is applied to the press-fit bolt 74, the rotational force Fc is applied to the pressure input Fd toward the anti-load side due to contact between the male screw of the screw shaft portion 74a of the press-fit bolt 74 and the female screw of the tap hole 32h. Converted. The press input Fd acts on the press-fit bolt 74 and is applied to the pinion shaft 34 from the head 74 b of the press-fit bolt 74. By applying this pressure input Fd to the pinion shaft 34, the pinion shaft 34 is press-fitted into the recess 32 b of the motor shaft 32. After the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32, the press-fit amount of the pinion shaft 34 into the recess 32b increases as the amount of rotation of the press-fit bolt 74 in the screw tightening direction increases.

  When the pinion shaft 34 is press-fitted until it hits the bottom surface of the recess 32b of the motor shaft 32, the press-fitting bolt 74 is rotated in the direction opposite to the screw tightening direction. The press-fit bolt 74 is rotated until the screw shaft portion 74a of the press-fit bolt 74 comes out of the tap hole 32h of the motor shaft 32. Thereafter, the screw shaft portion 74a of the press-fit bolt 74 is extracted from the insertion hole 34c of the pinion shaft 34. In addition, the press-fitting bolt 74 may be kept screwed into the tap hole 32h, or may be held in a state where it is inserted into the insertion hole 34c of the pinion shaft 34 using another member.

  Here, when the press-fit bolt 74 is screwed into the tapped hole 32h of the motor shaft 32, a reaction force Fe of the press-fit Fd acting on the press-fit bolt 74 acts. This reaction force Fe acts toward the load side (upper side in the figure) opposite to the pressure input Fd toward the counterload side (lower side in the figure), and cancels out with the pressure input Fd. Therefore, according to the present embodiment, when the pinion shaft 34 is press-fitted, the pressure input Fd that acts on the motor shaft 32 from the pinion shaft 34 is canceled with the reaction force Fe that acts on the motor shaft 32 from the press-fit bolt 74. Thus, the thrust load Fa acting on the load side bearing 36 can be reduced. For this reason, according to this embodiment, the pinion shaft 34 can be press-fitted into the recess 32b of the motor shaft 32 while suppressing the load on the anti-load side bearing 38, which can be used to improve the productivity of the motor 12.

  Further, in the present embodiment, when the pinion shaft 34 is press-fitted into the recess 32b of the motor shaft 32, the load receiving member 64 described in the above embodiment can be dispensed with. In the present embodiment, the pinion shaft 34 can be easily press-fitted into the recess 32 b of the motor shaft 32 by a simple configuration combining the insertion hole 34 c of the pinion shaft 34 and the tap hole 32 h of the motor shaft 32.

  In the above, the example of embodiment of this invention was demonstrated in detail. The above-described embodiments are merely specific examples for carrying out the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, deletions, etc. of constituent elements are possible without departing from the spirit of the invention defined in the claims. Is possible. In the above-described embodiment, the contents that can be changed in the design are described with the notation of “embodiment”, “in the embodiment”, and the like. Changes are not unacceptable. Moreover, the hatching given to the cross section of drawing does not limit the material of the hatched object.

  Although the example in which the motor 12 is integrated with the speed reducer 14 has been described, the motor 12 may not be integrated with the speed reducer 14. The speed reduction mechanism 20 of the speed reducer 14 has been described by way of an example of a distributed eccentric swing speed reduction mechanism, but the type thereof is not particularly limited. For example, a simple planetary planetary gear reduction mechanism or the like may be used. Although the pinion shaft 34 explained the example which transmits rotational power to the speed reduction mechanism 20 of the reduction gear 14, you may transmit rotational power to a to-be-driven device.

  The example in which the motor 12 includes the second anti-load side cover 48 has been described, but the second anti-load side cover 48 may not be provided. In this case, in order to obtain the effect described in the first embodiment, the external space 58 in which the anti-load side end surface 32d of the motor shaft 32 serving as the load transmission structure 40 is on the anti-load side with respect to the first anti-load side cover 46. As long as it is exposed. Further, in order to obtain the effect described in the second embodiment, the protruding member mounted on the mounting portion of the motor shaft 32 may be exposed to the external space 58 on the anti-load side from the first anti-load side cover 46. That's fine.

  The combination of the load transmission structure 40 described in the first to fourth embodiments and the insertion hole 34c of the pinion shaft 34 and the tap hole 32h of the motor shaft 32 described in the fifth embodiment are different from the other embodiments. May be combined with those described in. For example, as described in the second embodiment, the mounting portion is provided on the anti-load side end surface 32d of the motor shaft 32, and is held on the load side portion of the motor shaft 32 as described in the third and fourth embodiments. A part may be provided. Further, a combination of the insertion hole 34c of the pinion shaft 34 and the tap hole 32h of the motor shaft 32 as described in the fifth embodiment may be used while providing a mounting portion on the non-load side end surface 32d of the motor shaft 32. Good.

  The example in which the rotation angle detection device 62 is arranged around the non-load side end portion 32c of the motor shaft 32 has been described. The arrangement position of the rotation angle detection device 62 is not particularly limited, and may be accommodated in the motor casing 30, for example. Further, the motor 12 may not include the rotation angle detection device 62. The rotation angle detection device 62 has been described by taking a rotary encoder as an example, but a specific example thereof is not particularly limited, and may be, for example, a resolver.

DESCRIPTION OF SYMBOLS 12 ... Motor, 32 ... Motor shaft, 32a ... Load side end part, 32b ... Recessed part, 32d ... Anti-load side end face, 32h ... Tap hole, 34 ... Pinion shaft, 34c ... Insertion hole, 36 ... Load side bearing, 38 ... Anti-load-side bearing, 40 ... load transmission structure, 44 ... load-side cover, 46 ... first anti-load-side cover, 48 ... second anti-load-side cover, 58 ... external space, 64 ... load receiving member, 72 ... Contact member.

Claims (12)

A motor shaft having a recess at the load side end;
A pinion shaft pushed into the recess,
A load-side bearing and an anti-load-side bearing that support the motor shaft,
A motor comprising a load transmission structure for transmitting a thrust load acting on the motor shaft toward a non-load side to a load receiving member other than the load-side bearing and the anti-load side bearing. A first anti-load side cover for supporting the anti-load side bearing;
2. The motor according to claim 1, wherein the load transmission structure is an end surface on the anti-load side of the motor shaft exposed to an external space on the anti-load side with respect to the first anti-load side cover. A second anti-load side cover that covers the anti-load side end surface of the motor shaft;
The anti-load side end surface of the motor shaft serving as the load transmission structure is exposed to an external space on the anti-load side from the first anti-load side cover when the second anti-load side cover is not provided. The motor described. A first anti-load side cover for supporting the anti-load side bearing;
2. The motor according to claim 1, wherein an end surface of the motor shaft on a side opposite to the load side can be mounted with a protruding member that protrudes toward the side opposite to the load from the first counter load side cover, and has a mounting portion that serves as the load transmission structure. .   The motor according to claim 4, further comprising a second anti-load-side cover that covers an anti-load-side end surface of the motor shaft. A load side cover that supports the load side bearing and serves as the load receiving member;
6. The motor according to claim 1, wherein the motor shaft is capable of holding an abutting member for abutting against the load side cover, and has a holding portion serving as the load transmitting structure. A motor shaft having a recess at the load side end;
A pinion shaft pushed into the recess, and a motor comprising:
The pinion shaft is formed with an insertion hole for inserting a bolt from the load side,
A motor in which a tapped hole for screwing the bolt is formed at the bottom of the recess. A method for assembling a pinion shaft to a motor shaft of a motor,
The motor shaft has a recess at the load side end,
The motor includes a load side bearing and an anti-load side bearing that support the motor shaft,
A load transmission structure for allowing a thrust load acting on the motor shaft toward the non-load side to be transmitted to a load receiving member other than the load-side bearing and the anti-load side bearing;
A method for assembling a pinion shaft, wherein the thrust load is transmitted from the motor shaft to the load receiving member using the load transmission structure, and the pinion shaft is press-fitted into the recess. The motor includes a first anti-load side cover that supports the anti-load side bearing,
The load transmission structure is an end surface on the anti-load side of the motor shaft exposed to an external space on the anti-load side from the first anti-load side cover,
9. The method of assembling a pinion shaft according to claim 8, wherein the pinion shaft is press-fitted into the concave portion in a state in which a load receiving member disposed in the external space is in contact with the end surface on the opposite side of the motor shaft. The motor includes a first anti-load side cover that supports the anti-load side bearing,
The end surface on the side opposite to the load of the motor shaft can be mounted with a protruding member that protrudes toward the side opposite to the load, and has a mounting portion that serves as the load transmission structure.
9. The method of assembling a pinion shaft according to claim 8, wherein the pinion shaft is press-fitted into the concave portion in a state where a projecting member mounted on the mounting portion is in contact with a load receiving member disposed in an external space. The motor includes a load side cover that supports the load side bearing and serves as the load receiving member,
The motor shaft is capable of holding a contact member, and has a holding portion serving as the load transmission structure.
The method of assembling the pinion shaft according to claim 8, wherein the pinion shaft is press-fitted into the concave portion in a state where the contact member held by the holding portion is in contact with the load side cover. A method for assembling a pinion shaft to a motor shaft of a motor,
The motor shaft has a recess at the load side end,
The pinion shaft is formed with an insertion hole for inserting a bolt from the load side,
A tapped hole is formed at the bottom of the recess,
A method of assembling a pinion shaft, wherein a bolt inserted into the insertion hole is screwed into the tap hole, thereby applying a pressure input from the bolt to the pinion shaft and press-fitting the pinion shaft into the recess.

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