JP5737260B2 - Bolt fastening structure, actuator - Google Patents

Description

  The present invention relates to a fastening structure using a bolt and an actuator having the same.

  The fastening structure using the bolt is required to be devised so as not to come off when the bolt is loosened. Patent Document 1 describes a structure that prevents a screw from falling off by fixing a cover to a body of an air flow rate measuring device with a screw (bolt) and pressing the head of the screw with a retaining ring. In this example, fixing with screws is performed at two locations, but one retaining ring is used for one screw.

JP-A-5-248905

  An object of the present invention is to prevent all bolts from being removed from a member in a bolt fastening structure in which a plurality of members are fastened by a plurality of bolts arranged along one circle.

  In order to solve the above-mentioned problems, the present invention provides a plurality of bolts (screw parts having a head) arranged along one circle, and a plurality of bolt mounting portions arranged in contact with each other in the axial direction of the bolts. The member is fastened, and one of the plurality of members is set in advance in a position separated from the bolt mounting portion by a predetermined distance in the axial direction of the bolt (preset between the bolt head). A retaining ring for a retaining ring at a position where no clearance is generated or where no clearance is generated), and a retaining ring that is overlapped with all heads of the plurality of bolts in the radial direction of the bolt is attached to the mounting groove. A bolt fastening structure is provided.

According to this bolt fastening structure, the position of the retaining ring mounting groove is set such that the bolt head and the retaining ring come into contact with each other with the bolt and retaining ring attached, or a preset clearance (for example, 1) When the bolts are loosened, the heads of all the bolts come into contact with the retaining ring, so that all the bolts cannot be removed from the member.
When there is a large dimensional difference between the plurality of bolts to be used, it is difficult to set the retaining grooves for the retaining rings so that the heads of all the bolts and the retaining rings are in contact with each other. On the other hand, if a retaining groove for the retaining ring is set at a position where a preset gap is generated between the head of the bolt and the retaining ring, the retaining ring can be used even when the dimensional difference between the plurality of bolts is large. Can be mounted in the mounting groove.

When the retaining groove of the retaining ring is set at a position where a preset clearance is generated between the bolt head and the retaining ring, (1) The bolt head is part of the plurality of bolts In other bolts, there is a state in which a gap is generated between the retaining ring and the head, or (2) a state in which a gap is generated between the head and the retaining ring of all the bolts. Therefore, since the formation position of the retaining ring mounting groove can be set according to the tolerance of the bolt to be used, the retaining ring can be securely attached without using a high dimensional accuracy bolt.
As an example of this bolt fastening structure, the retaining ring is a retaining ring for a hole, the mounting groove is a circumferential groove formed on a cylindrical inner peripheral surface, and the retaining ring for a hole is attached to the circumferential groove. Are listed.

  According to the present invention, a plate that receives the axial force of a rolling bearing that rotatably supports a screw shaft or nut of a ball screw with respect to the housing with a plurality of bolts arranged along one circle is provided on the housing. It is fastened to the bolt mounting portion, and a position set between the inner peripheral surface of the housing and a predetermined distance from the bolt mounting portion in the axial direction of the bolt (a gap is set between the bolt head and the bolt). A bolt fastening structure is provided in which a circumferential groove is formed at a position, and a retaining ring for a hole that overlaps all the heads of the plurality of bolts in the radial direction of the bolt is attached to the circumferential groove.

  According to this bolt fastening structure, the position of the circumferential groove to which the retaining ring for the hole is attached is such that the bolt head and the retaining ring for the hole come into contact with each other in the state where the bolt and the retaining ring for the hole are attached. By setting the position where a set gap (for example, about 1 to 2 mm) is generated, when the bolts are loosened, the heads of all the bolts come into contact with the retaining rings for the holes. I can not.

  According to the present invention, a plurality of bolts arranged along one circle, two shafts having flange joints arranged in contact with each other in the axial direction of the bolts are fastened, and one of the two shafts is fastened. The shaft is formed with a circumferential groove at a preset position (a position where a gap is set between the head of the bolt) and all the heads of the plurality of bolts and the bolt are formed in the circumferential groove. A bolt fastening structure to which a retaining ring for a shaft overlapping in the radial direction is attached.

  According to this bolt fastening structure, the position of the circumferential groove to which the retaining ring for the shaft is attached is such that the head of the bolt and the retaining ring for the shaft come into contact with each other in the state where the bolt and the retaining ring for the shaft are attached. By setting the position where a set gap (for example, about 1 to 2 mm) is generated, when the bolts are loosened, the heads of all the bolts come into contact with the retaining ring for the shaft. I can not.

  The present invention also provides a ball screw, a housing in which the ball screw is inserted, an output rod arranged in the housing, and a portion of the ball screw in which a spiral groove is not formed with respect to the housing. The output rod has a bottomed hole for inserting a portion in which the spiral groove of the screw shaft is formed, and the nut of the ball screw is connected to the output rod. An actuator fixed to the open end, wherein a plate that receives the axial force of the outer ring of the rolling bearing with a plurality of bolts arranged along one circle is fastened to the bolt mounting portion of the housing, A circumferential groove is formed on the inner circumferential surface of the housing at a position away from the bolt mounting portion in the axial direction of the bolt by a preset distance, and the plurality of bolts are formed in the circumferential groove. To provide an actuator, wherein a hole for retaining ring overlap in the radial direction of the all of the head bolts are attached.

  According to the bolt fastening structure of the present invention, when the bolts are loosened, the heads of all the bolts come into contact with the retaining ring, so that all the bolts can be prevented from coming off from the member.

It is sectional drawing which shows the actuator which has a bolt fastening structure equivalent to 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is a figure explaining the example from which the AA cross section of FIG. 1 differs from FIG. It is a fragmentary sectional view of the actuator of Drawing 1, and is a figure explaining the example from which the attaching part of a retaining ring differs from Drawing 1. It is a figure explaining the example from which the outer diameter and internal diameter of the large diameter part of a housing, and the position which attaches the retaining ring in an axial direction differ from FIG. It is a side view which shows the bolt fastening structure equivalent to 2nd Embodiment of this invention. It is BB sectional drawing of FIG. It is a figure explaining the example which provided the rotation prevention member of the retaining ring in the bolt fastening structure shown in FIG. It is BB sectional drawing of FIG.

Embodiments of the present invention will be described below.
[First Embodiment]
The actuator shown in FIG. 1 includes a motor 1, a ball screw 2, a housing 3, an output rod 4, a rolling bearing 5, a plate (bolt mounting portion) 6 made of a perforated disk, and a retaining ring 7 for a hole. And a ring 8, bolts 9 and 10, a wear ring 11, a bush 12, a seal 13, a coupling 14, and a hole retaining ring 15.

The ball screw 2 includes a screw shaft 21, a nut 22, and a ball 23. A base end portion 21 a of the screw shaft 21 is coupled to the rotating shaft 1 a of the motor 1 by a coupling 14. The flange 19 of the case of the motor 1 and the flange 35 of the housing 3 are fixed with bolts 10.
A rolling bearing 5 is attached between the screw shaft 21 and the housing 3. The inner ring 51 of the rolling bearing 5 is lightly press-fitted into the mounting portion 21c from the tapered portion 21b side of the screw shaft 21 and brought into contact with the shoulder portion 21d. It is fixed. That is, the inner ring 51 is restrained in the axial direction with respect to the screw shaft 21 by the ring 8 and the shoulder portion 21d that are externally fitted to the tapered portion 21b.

  The outer ring 52 of the rolling bearing 5 is attached to the bolt attachment portion 31 of the housing 3 using the plate 6 and the four bolts 9. A shoulder portion 31 a that presses one end surface in the axial direction of the outer ring 52 is formed on the inner peripheral surface of the bolt mounting portion 31. The bolt mounting portion 31 includes a flange surface (a surface perpendicular to the axial direction) 31b that extends along the other axial end surface of the outer ring 52, and four female screws 31c having the flange surface 31b as openings. The four female screws 31c are arranged at equal intervals along a circle C shown in FIG.

The plate 6 has four through holes 61 arranged at equal intervals along the circle C shown in FIG. 2, and four bolts 9 arranged at equal intervals along the circle C. It is fixed to the bolt mounting portion 31.
When the outer ring 52 is mounted, the outer ring 52 is clearance-fitted to the inner peripheral surface of the bolt mounting portion 31, and one end surface in the axial direction of the outer ring 52 is applied to the shoulder portion 31a. 6, the flange surface 31 b and the other end surface of the outer ring 52 in the axial direction are pressed by the plate 6, the bolt 9 is inserted from the through hole 61 of the plate 6, and is screwed into the female screw 31 c of the bolt mounting portion 31.

As a result, the outer ring 52 of the rolling bearing 5 is restrained in the axial direction with respect to the housing 3 by the shoulder 31 a on the inner peripheral surface of the housing 3 and the plate 6. That is, the plate 6 receives the axial force of the rolling bearing 5.
The housing 3 is divided in the axial direction into a large-diameter portion 32 on the motor 1 side and a small-diameter portion 33 on the output rod 4 side with the bolt mounting portion 31 interposed therebetween. On the cylindrical inner peripheral surface 32 a of the large diameter portion 32, a peripheral groove 32 b for fitting the hole retaining ring 7 is formed. The formation position of the circumferential groove 32b is set to a position where the gap between the head of the bolt 9 and the retaining ring 7 for the hole is about 1 mm in a state where the bolt 9 is attached to the bolt attachment portion 31. As shown in FIG. 2, the retaining ring 7 for holes overlaps the heads of all bolts 9 in the radial direction of the bolts 9.

In the small diameter portion 33 of the housing 3, the screw shaft 21 of the ball screw 2 is inserted into the bottomed hole 41 of the output rod 4, and a part of the nut 22 in the axial direction is opened at the open end of the large diameter portion 42 of the output rod 4. Is fitted. The output rod 4 and the nut 22 are fixed so as to rotate together and move together in the axial direction.
The large-diameter portion 42 of the output rod 4 has an outer peripheral groove 42a, and the wear ring 11 is attached to the outer peripheral groove 42a. The wear ring 11 allows relative movement between the output rod 4 and the housing 3 while closing the gap between the output rod 4 and the housing 3. The bush 12 and the seal 13 are arranged at the distal end portion of the small diameter portion 33 of the housing 3 in order to seal between the housing 3 and the output rod 4. The hole retaining ring 15 is attached to the distal end portion of the housing 3 as a seal for preventing the seal 13 from coming off.

An attachment hole 43a for attaching a drive target member (such as a link mechanism that does not rotate the output rod 4) is formed in the distal end portion 43 of the output rod 4.
In the actuator of this embodiment, the bolt fastening structure includes four bolts 9, a plate 6, a bolt mounting portion 31 of the housing 3, a circumferential groove 32 b provided in the large diameter portion 32 of the housing 3, and a hole stopper. It is composed of a ring 7. In this bolt fastening structure, as described above, in order to attach the outer ring 52 to the housing 3, the plate 6 is fixed to the bolt attachment portion 31 of the housing 3 with the four bolts 9, and then the hole is formed in the circumferential groove 32 b of the housing 3. This is caused by fitting the retaining ring 7.

According to the bolt fastening structure of this embodiment, even when the bolt 9 is loosened due to vibration during use of the actuator, all the bolts 9 come into contact with the retaining ring 7 for holes. It is prevented from falling out.
The actuator shown in FIG. 1 can be used by attaching a shift lever of an outboard motor to the attachment hole 43a of the distal end portion 43 of the output rod 4. When the actuator shown in FIG. 1 is used for a shift lever of an outboard motor, the clearance between the head of the bolt 9 and the retaining ring 7 for holes is preferably about 1 mm.

Further, in the example of FIG. 1, if a push nut hole retaining ring or a CR retaining ring is used instead of the hole retaining ring 7, it is not necessary to process the circumferential groove 32 b in the large diameter portion 32. Even in the case of processing, rough processing is sufficient, so that the manufacturing cost is reduced.
The example shown in FIG. 3 is an example in which the AA cross section of FIG. 1 is different from FIG. In this example, a convex portion 65 that extends in the axial direction beyond the attachment position of the hole retaining ring 7 is formed on one end surface of the plate 6 in the axial direction. By disposing the end portions 7a of the retaining ring for holes 7 on both sides of the convex portion 65, the retaining ring for holes 7 is prevented from rotating. Instead of this, the retaining ring 7 for holes may be provided with a convex portion, and a concave portion into which the convex portion is inserted may be provided in the circumferential groove 32b to prevent the retaining ring from rotating.

  The example shown in FIG. 4 is an example in which the shape of the portion to which the retaining ring 7 for holes of the housing 3 is attached is different from that in FIG. In this example, a circumferential groove 32 d serving as a locking portion of the retaining ring 7 for holes and a locking portion of the plate 6 is provided on the inner peripheral surface 32 a of the large-diameter portion 32 of the housing 3. One end surface in the axial direction of the circumferential groove 32d forms a flange surface 31b of the bolt mounting portion 31, and the hole retaining ring 7 is locked to the other axial end surface 32e of the circumferential groove 32d. In this example, since the flange surface 31b, which is the seating surface of the plate 6, is formed simultaneously with the formation of the circumferential groove 32d for attaching the hole retaining ring 7, the processing cost is reduced as compared with the example shown in FIG.

  The example shown in FIG. 5 is an example in which the outer diameter and inner diameter of the large-diameter portion 32 of the housing 3 are larger than the example of FIG. 1 and the position where the hole retaining ring 7 is attached in the axial direction is also different from FIG. In this example, as compared with the example shown in FIG. 1, the position where the retaining ring 7 for holes is attached is separated from the bolt attaching portion 31. Further, the hole retaining ring 7 and the head of the bolt 9 do not overlap in the radial direction. An annular member 78 is disposed between the hole retaining ring 7 and the bolt 9. Further, a step portion 34 for arranging the annular member 78 is formed between the bolt mounting portion 31 and the large diameter portion 32 of the housing 3.

  A disc portion 78 a is formed on the inner peripheral side of the annular member 78. The disc part 78a of the annular member 78 overlaps the head of the bolt 9 in the radial direction. The outer diameter of the annular member 78 is substantially the same as the inner diameter of the large diameter portion 32 of the housing 3, and the outer diameter of the hole retaining ring 7 is larger than the inner diameter of the large diameter portion 32. The annular member 78 is disposed inside the step portion 34, and the hole retaining ring 7 is attached to a circumferential groove 32 b provided on the inner peripheral surface 32 a of the large diameter portion 32.

Thus, when the position where the retaining ring for the hole is attached is larger than the position where about 1-2 mm is generated between the head of the bolt and the retaining ring for the hole with the bolt and the retaining ring for the hole attached, An annular member is arranged between the retaining ring and the head of the bolt so that the annular member and the head of the bolt are in contact with each other, or a gap of about 1 to 2 mm is generated between them. Thereby, when a bolt loosens, since the head part of all the bolts contacts an annular member, it can prevent that all the bolts pull out from the member fastened with the bolt.
If the retaining ring for the hole and the head of the bolt do not overlap in the radial direction, an annular member having a disk part on the inner peripheral side is disposed between the retaining ring for the hole and the head of the bolt, The disk part of the annular member and the head part of the bolt are overlapped in the radial direction.

[Second Embodiment]
As shown in FIG. 6, in the bolt fastening structure of this embodiment, a shaft 81 having a flange joint (bolt mounting portion) 81a and a shaft 82 having a flange joint (bolt mounting portion) 82a are both flange joints 81a and 82a. In FIG. 4, the bolts 9 are fastened. The four bolts 9 are arranged at equal intervals along a circle C shown in FIG.

A circumferential groove 81b is formed at the end of the shaft 81 on the flange joint 81a side (a position described below). A through hole 81c through which the shaft portion of the bolt 9 passes is formed in the flange joint 81a. The flange joint 82a is formed with a female screw 82b for screwing the male screw of the bolt 9. A shaft retaining ring 71 is attached to the circumferential groove 81 b of the shaft 81.
The circumferential groove 81b is formed at a position where the clearance between the head of the bolt 9 and the retaining ring 71 for the shaft is about 1 mm when the bolt 9 is attached to the flange joints 81a and 82a. Further, as shown in FIG. 7, the shaft retaining ring 71 overlaps the heads of all the bolts 9 in the radial direction of the bolts 9.

As a method for assembling the bolt fastening structure of this embodiment, first, the flange joints 81a and 82a of both shafts 81 and 82 are brought into contact with each other with the through hole 81c and the female screw 82b, and then the bolt 9 from the through hole 81c side. And the male screw of the bolt 9 is screwed into the female screw 82b of the flange joint 82a. After the shafts 81 and 82 are coupled in this way, the shaft retaining ring 71 is fitted into the circumferential groove 81 b of the shaft 81.
According to the bolt fastening structure of this embodiment, even when the bolt 9 is loosened, all the bolts 9 are in contact with the shaft retaining ring 71, so that all the bolts 9 are prevented from falling off.

If a push nut shaft retaining ring or a CS type retaining ring is used instead of the shaft retaining ring 71, it is not necessary to process the circumferential groove 81b in the shaft 81, or rough machining is sufficient even when processing. Therefore, the manufacturing cost is reduced.
In the example shown in FIGS. 8 and 9, a convex portion 81e extending in the axial direction beyond the position of the circumferential groove 81b of the shaft 81 is formed on the axial end surface of the flange joint 81a on the side where the head of the bolt 9 is disposed. ing. And the rotation of the shaft retaining ring 71 is prevented by arranging the end portions 17a of the shaft retaining ring 71 on both sides of the convex portion 81e. Instead, the rotation of the retaining ring may be prevented by providing a convex portion on the shaft retaining ring 71 and providing the concave portion into which the convex portion is inserted in the circumferential groove 81b.

DESCRIPTION OF SYMBOLS 1 Motor 1a Motor rotating shaft 2 Ball screw 21 Screw shaft 21a Screw shaft base end 21b Screw shaft taper portion 21c Screw shaft mounting portion 21d Screw shaft shoulder portion 22 Nut 23 Ball 3 Housing 31 Housing bolt mounting portion 31a Shoulder portion 31b Flange surface 31c Female screw 32 Large diameter portion of housing 32a Columnar inner peripheral surface 32b Circumferential groove 32d Peripheral groove 32e Other end surface in the axial direction of the circumferential groove 33 Small diameter portion of the housing 34 Housing step portion 35 Housing flange 4 Output rod 41 Bottom hole of output rod 42 Large diameter portion of output rod 42a Outer peripheral groove 43 Tip of output rod 43a Mounting hole 5 Rolling bearing 51 Inner ring 52 Outer ring 6 Plate (bolt mounting portion)
61 Plate through-hole 65 Protruding portion 7 Retaining ring for hole 7a End of retaining ring for hole 71 Retaining ring for shaft 71a End of retaining ring for shaft 8 Ring 81 Shaft 81a Flange joint (bolt mounting part)
81b Circumferential groove 81c Through hole 81e Convex part 82 Shaft 82a Flange joint (bolt mounting part)
82b Female thread 9 Bolt 10 Bolt 11 Wear ring 12 Bush 13 Seal 14 Coupling 15 Retaining ring for hole 19 Motor case flange

Claims (5)

With a plurality of bolts arranged along one circle, a plurality of members having bolt mounting portions arranged in contact with each other in the axial direction of the bolts are fastened,
One of the plurality of members has a retaining ring mounting groove at a position away from the bolt mounting portion by a preset distance in the axial direction of the bolt,
Retaining rings that overlap all the heads of the plurality of bolts and the bolts in the radial direction are attached to the mounting grooves,
The bolt fastening structure in which the mounting groove is formed at a position where a gap is set in advance according to the tolerance of the bolt used between the head of the bolt and the retaining ring. The retaining ring is a retaining ring for a hole,
The bolt fastening structure according to claim 1, wherein the attachment groove is a circumferential groove formed on a cylindrical inner circumferential surface, and the hole retaining ring is attached to the circumferential groove. A plate that receives the axial force of a rolling bearing that rotatably supports the screw shaft or nut of the ball screw with respect to the housing with a plurality of bolts arranged along one circle is fastened to the bolt mounting portion of the housing. ,
A circumferential groove is formed on the inner circumferential surface of the housing at a position away from the bolt mounting portion by a preset distance in the axial direction of the bolt,
A retaining ring for a hole that overlaps all the heads of the plurality of bolts in the radial direction of the bolts is attached to the circumferential groove,
The position where the circumferential groove is formed is a bolt fastening structure in which a gap which is set in advance according to the tolerance of the bolt used between the head of the bolt and the retaining ring for the hole is set. With two or more bolts arranged along one circle, two shafts having flange joints arranged in contact with each other in the axial direction of the bolts are fastened,
One of the two shafts is formed with a circumferential groove at a preset position, and the shaft stopper overlaps the circumferential groove with all heads of the plurality of bolts in the radial direction of the bolt. A ring is attached,
The position where the circumferential groove is formed is a bolt fastening structure in which a gap which is set in advance according to the tolerance of the bolt used between the head of the bolt and the retaining ring for the shaft is set. A ball screw, a housing in which the ball screw is inserted, an output rod arranged in the housing, and a portion of the ball screw in which a spiral groove is not formed are rotatably attached to the housing. A rolling bearing,
The output rod has a bottomed hole for inserting a portion of the screw shaft in which a spiral groove is formed, and the nut of the ball screw is fixed to the open end of the output rod;
With a plurality of bolts arranged along one circle, a plate that receives the axial force of the outer ring of the rolling bearing is fastened to the bolt mounting portion of the housing,
A circumferential groove is formed on the inner circumferential surface of the housing at a position away from the bolt mounting portion by a preset distance in the axial direction of the bolt,
A retaining ring for a hole that overlaps all the heads of the plurality of bolts in the radial direction of the bolts is attached to the circumferential groove,
The formation position of the circumferential groove is set to a position where a preset gap is generated according to a tolerance of the bolt used between the head of the bolt and the retaining ring for the hole. Actuator.

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