CN110873110B

CN110873110B - Screw structure, hydraulic drive device, nut, and shaft member

Info

Publication number: CN110873110B
Application number: CN201910833815.0A
Authority: CN
Inventors: 矢田部伦章
Original assignee: Nabtesco Corp
Current assignee: Nabtesco Corp
Priority date: 2018-09-04
Filing date: 2019-09-04
Publication date: 2023-10-03
Anticipated expiration: 2039-09-04
Also published as: JP7194538B2; KR20200027429A; JP2020037977A; CN110873110A

Abstract

The invention provides a screw thread structure, a hydraulic drive device, a nut and a shaft member, which can reattach the nut to the shaft member in a state of being limited to rotate relative to the shaft member without replacing the shaft member and the nut when removing the nut limited to rotate relative to the shaft member. The present invention is provided with: a nut (30) having a first threaded portion (30A) on the inner circumferential surface, wherein the nut (30) is deformed or moved by applying a radial force to the nut (30); and a fixed housing (23) as a shaft member, which has a second screw thread portion (23A) on the outer circumferential surface that engages with the first screw thread portion (30A) of the nut (30), wherein the relative rotation between the fixed housing (23) and the nut (30) is restricted by bringing the fixed housing (23) into contact with the deformed or moved nut (30), and wherein the relative rotation between the fixed housing (23) and the nut (30) is allowed after the force is released.

Description

Screw structure, hydraulic drive device, nut, and shaft member

Technical Field

The present invention relates to a screw structure in which a nut is mounted in a state in which rotation is restricted with respect to a shaft member, a hydraulic drive device having such a structure, a nut, and a shaft member.

Background

Patent document 1 discloses a hydraulic drive device including: a bearing is fitted to the outside of a cylindrical housing of the hydraulic motor, and a cylindrical ring gear disposed radially outside the housing is rotatably supported by the bearing.

In the hydraulic drive device of patent document 1, a ring nut is further attached to a housing of the hydraulic motor, and the ring nut is screwed toward the bearing, thereby restricting axial movement of the bearing. Further, a pin having a protrusion on the outer peripheral surface is inserted into the housing, and the protrusion of the pin is engaged with the female screw portion of the inner peripheral surface of the ring nut, whereby the ring nut is restricted from rotating.

As the rotation restricting structure described above, a structure using a stopper screw as disclosed in patent document 2 has been conventionally known. In this configuration, the external thread portion of the stopper screw screwed into the housing is caused to bite into the internal thread portion of the inner peripheral surface of the ring nut, whereby the ring nut is restrained from rotating.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2015-14318

Patent document 2: japanese Kokai publication Sho-62-30579

Disclosure of Invention

Problems to be solved by the invention

In the above-described conventional structure, the female screw portion of the ring nut may be irreversibly deformed when the rotation of the ring nut is restricted, and the male screw portion on the housing side may be irretrievably deformed due to interference with the deformed female screw portion when the ring nut is detached from the housing (shaft member). Therefore, at least one of the internal thread portion of the ring nut and the external thread portion of the housing cannot be reused, and therefore, it is necessary to replace at least one of the ring nut and the housing with a new component at the time of refastening.

The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a screw structure, a hydraulic drive device, a nut, and a shaft member as follows: when the nut whose rotation is restricted with respect to the shaft member is removed from the shaft member, the nut can be reattached to the shaft member in a state in which the rotation is restricted with respect to the shaft member without replacing the shaft member and the nut.

Solution for solving the problem

(1) The present invention is a screw thread structure, comprising: a nut having a first screw portion on an inner circumferential surface thereof, the nut being deformed or moved by a radial force applied thereto; and a shaft member having a second screw portion on an outer peripheral surface thereof, the second screw portion being engaged with the first screw portion of the nut, the shaft member being brought into contact with the deformed or moved nut to restrict relative rotation between the shaft member and the nut, and the shaft member and the nut being allowed to relatively rotate after the force is released.

(2) The present invention is a screw thread structure, comprising: a shaft member having a second screw portion on an outer peripheral surface, the shaft member being deformed or moved by a radial force applied thereto; and a nut having a first screw portion engaged with the second screw portion of the shaft member on an inner peripheral surface thereof, the nut being brought into contact with the deformed or moved shaft member to restrict relative rotation between the nut and the shaft member, and the nut and the shaft member being allowed to relatively rotate after the force is released.

In the screw structure of (1) or (2), after the force is released, one of the nut and the shaft member deformed or moved in the radial direction by the force may be pushed back by the screw portion of the other of the nut and the shaft member and then moved so as to move on the screw portion of the other or not to interfere with the screw portion.

In the screw structure of (1) or (2), one of the nut and the shaft member may have a contact portion, the contact portion may be deformed or moved by the force applied thereto, and the other of the nut and the shaft member may have a receiving portion that contacts the deformed or moved contact portion, and after the force is released, the contact portion may not interfere with the receiving portion, and the contact portion and the receiving portion may not interfere with the screw portion on the other side.

The screw structure of (1) may further include a male screw member integrally formed in a tapered shape or having a tapered portion in a part thereof, wherein the nut includes a rotation restricting operation screw hole extending in an axial direction and having a female screw portion engaged with the tapered male screw member or the tapered portion of the male screw member, and the force radially inward from the tapered male screw member or the tapered portion of the male screw member acts on the nut in accordance with tightening of the male screw member with respect to the rotation restricting operation screw hole to deform the nut.

In this case, the shaft member may be in contact with the deformed nut at a portion of the second threaded portion having a lower thread than the other portion.

The screw structure of (1) or (2) may further include an external screw member having a tapered portion tapered on a screw-in side at a distal end, wherein one of the nut and the shaft member deformed or moved by the force includes: a rotation restricting operation screw hole extending in an axial direction and engaged with the male screw member; and a communication hole penetrating from the rotation restricting operation screw hole in a radial direction toward the other of the nut and the shaft member, wherein one of the nut and the shaft member includes a moving body disposed in the communication hole so as to contact the tapered portion in accordance with tightening of the male screw member, and the moving body is disposed in the communication hole so as to: in a state before the contact with the tapered portion of the male screw member, the force acts on the moving body in accordance with the contact between the moving body and the tapered portion generated with the tightening of the male screw member, so that the moving body is moved toward the other of the nut and the shaft member, with respect to the thread of the other of the nut and the shaft member, to a position not interfering with the top of the thread.

In this case, the rotation limiting operation screw hole may be formed in the nut, and an inner peripheral surface of the nut may be provided with: the first screw part is positioned at the side of loosening the external screw member; and a non-threaded portion having a diameter larger than a diameter of a thread of the first threaded portion, the non-threaded portion being formed with the communication hole, the side on which the nut is loosened and the side on which the male threaded member is loosened being in the same direction, the movable body that has moved in a radial direction due to the force after releasing the force being pushed back by the second threaded portion of the shaft member, and being moved on or not interfering with the second threaded portion.

In the screw structure of (2), the shaft member may further include a male screw member engaged with a rotation restriction operation screw hole formed in an axial end surface of the shaft member, and the force for moving the male screw member may be applied to the male screw member so that the male screw member protrudes from the rotation restriction operation screw hole toward the nut side in a radial direction, and an outer peripheral surface of the shaft member may be provided with: the second screw part is separated from the axial end surface and positioned on the side into which the external screw member is screwed; and a non-threaded portion located between the axial end face and the second threaded portion and having a diameter smaller than a diameter of a thread of the second threaded portion, wherein the male screw member is located in the non-threaded portion, a side on which the nut is loosened and a side on which the male screw member is loosened are in the same direction, the nut does not interfere with the male screw member after the force is released, and the male screw member does not interfere with the first threaded portion.

In the screw structure of (2), the shaft member may include: an externally threaded member engaged with a rotation restricting operation threaded hole formed in an axial end face of the shaft member; and a moving body that is independent of the male screw member, and that is moved in a radial direction toward the nut side by the force according to the contact generated by the tightening of the male screw member, and that is capable of being retracted to a position that does not interfere with the top of the thread of the first screw portion of the nut in a state before the moving body comes into contact with the male screw member, wherein an outer peripheral surface of the shaft member is provided with: the second screw part is separated from the axial end surface and positioned on the side into which the external screw member is screwed; and a non-threaded portion having a diameter smaller than a diameter of a thread of the second threaded portion, the moving body being located in the same direction on a side of the non-threaded portion where the nut is loosened and a side of the male screw member is loosened, the nut not interfering with the moving body after the force is released, and the moving body not interfering with the first threaded portion.

The present invention is also a hydraulic drive device including: a nut having a first screw portion on an inner circumferential surface thereof, the nut being deformed or moved by a radial force applied thereto; a hydraulic motor having a cylindrical fixed housing, the cylindrical fixed housing having a second screw portion on an outer circumferential surface thereof, the second screw portion being engaged with the first screw portion of the nut, the hydraulic motor being configured to restrict relative rotation between the cylindrical fixed housing and the nut by bringing the cylindrical fixed housing into contact with the deformed or moved nut, and to permit relative rotation between the cylindrical fixed housing and the nut after the force is released; and a rotary housing provided on an outer peripheral surface of the fixed housing, and rotatably supported by the fixed housing via a bearing whose axial movement is regulated by the nut.

The present invention is also a hydraulic drive device including: a hydraulic motor having a cylindrical fixed housing, the cylindrical fixed housing having a second screw portion on an outer peripheral surface, the cylindrical fixed housing being deformed or moved by applying a radial force to the cylindrical fixed housing; a nut having a first screw portion engaged with the second screw portion of the fixed housing on an inner peripheral surface thereof, the nut being brought into contact with the deformed or moved fixed housing to restrict relative rotation between the nut and the fixed housing, and allowing relative rotation between the nut and the fixed housing after releasing the force; and a rotary housing provided on an outer peripheral surface of the fixed housing, and rotatably supported by the fixed housing via a bearing whose axial movement is regulated by the nut.

The present invention is a nut having a first threaded portion on an inner peripheral surface thereof, the nut being deformed or moved by applying a radial force to the nut, wherein the nut is brought into contact with a shaft member having a second threaded portion on an outer peripheral surface thereof to restrict relative rotation between the nut and the shaft member, and wherein the nut and the shaft member are allowed to relatively rotate after the force is released.

The present invention is also a shaft member having a second screw portion on an outer peripheral surface, the shaft member being deformed or moved by applying a radial force to the shaft member, wherein the relative rotation between the shaft member and a nut having a first screw portion on an inner peripheral surface is restricted by bringing the shaft member into contact with the nut, and the relative rotation between the shaft member and the nut is allowed after the force is released.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, when the nut restricted from rotating with respect to the shaft member is removed from the shaft member, the nut can be reattached to the shaft member in a state in which the rotation of the nut with respect to the shaft member is restricted without replacing the shaft member and the nut.

Drawings

Fig. 1 is a diagram showing a hydraulic drive device having a screw structure according to embodiment 1 of the present invention.

Fig. 2 is an enlarged view of a main part of fig. 1 for explaining a screw structure of embodiment 1.

Fig. 3 is a view for explaining a contact state of the screw structure of embodiment 1.

Fig. 4 is a diagram showing a screw structure according to embodiment 2 of the present invention.

Fig. 5 is a diagram showing a screw structure according to embodiment 3 of the present invention.

Fig. 6 is a diagram showing a state before contact of the screw structure according to embodiment 3.

Fig. 7 is a view showing a screw structure according to embodiment 4 of the present invention.

Fig. 8 is a diagram showing a screw structure according to embodiment 5 of the present invention.

Fig. 9 is a diagram showing a screw structure according to embodiment 6 of the present invention.

Fig. 10 is a view showing a screw structure according to embodiment 7 of the present invention.

Description of the reference numerals

1. A hydraulic drive device; 2. a hydraulic motor with a speed reducer; 2A, a hydraulic motor; 2B, a speed reducer; 23. a fixed housing; 23A, a second threaded portion; 23E, axial end face; 23F, a non-threaded portion; 28. a bearing; 30. a ring nut; 30A, a first threaded portion; 30B, a non-threaded portion; 31. 61, a screw hole for rotation restriction operation; 34. 64, a communication hole; 40. an external screw member; 41. a taper portion; 42. a threaded rod portion; 101. a contact portion; 102. and a receiving part.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(embodiment 1)

Fig. 1 is a schematic cross-sectional view of a hydraulic drive device 1 having a screw structure according to embodiment 1. First, the structure of the hydraulic drive device 1 will be described.

The hydraulic drive device 1 shown in fig. 1 includes a hydraulic motor 2 with a speed reducer, and the hydraulic motor 2 with a speed reducer is configured such that the hydraulic motor 2A and the speed reducer 2B are integrally formed. The hydraulic motor 2A has: a rotation shaft member 21; a hydraulic motor mechanism 22 that drives the rotation shaft member 21 according to the supply and discharge of the hydraulic oil; and a fixed housing 23 formed in a cylindrical shape coaxially arranged with the rotary shaft member 21, and accommodating the rotary shaft member 21 and the hydraulic motor mechanism 22 therein.

The rotation shaft member 21 protrudes from the fixed housing 23 to one side in the axial direction (right side in fig. 1) and is coupled to the speed reducer 2B. In fig. 1, reference numeral C1 denotes a central axis of the rotation shaft member 21, and the rotation shaft member 21 is driven by the hydraulic motor mechanism 22 to rotate around the central axis C1.

In the present embodiment, the direction refers to a direction extending on the central axis C1 or a direction along the central axis C1 in a case called an axial direction. In the case of simply called a radial direction, the direction refers to a direction orthogonal to the central axis C1.

The hydraulic motor mechanism 22 is the following mechanism: working oil is supplied from the outside and discharged to the outside, thereby rotating the rotation shaft member 21 with respect to the stationary housing 23. The hydraulic motor 2A in the present embodiment is a plunger motor, and the hydraulic motor mechanism 22 includes a cylinder block, a swash plate, or the like, and the hydraulic motor 2A may be a vane motor or a gear motor.

The decelerator 2B has: a speed reducing mechanism 26 coupled to a portion of the rotation shaft member 21 protruding from the fixed housing 23 toward one side in the axial direction; and a rotary case 27 formed in a cylindrical shape coaxially arranged with the rotary shaft member 21, and accommodating the speed reduction mechanism 26 therein. The rotary case 27 covers a portion of one side in the axial direction of the fixed case 23 with a portion of the other side (left side in fig. 1) in the axial direction thereof, and houses the speed reduction mechanism 26 in the interior of the portion of one side in the axial direction thereof.

By sandwiching two bearings 28 between the rotary case 27 and the fixed case 23, the rotary case 27 is rotatably supported by the fixed case 23. The speed reducing mechanism 26 reduces the rotation of the rotation shaft member 21 and transmits the rotation to the rotation housing 27, and the rotation housing 27 is rotatably supported by the fixed housing 23, so that the rotation housing 27 rotates about the central axis C1 when the rotation is transmitted from the speed reducing mechanism 26.

In the present embodiment, after the two bearings 28 are fitted to the outer peripheral surface of the fixed housing 23, the ring nut 30 is screwed in, and the ring nut 30 is disposed so as to restrict the axial movement of the bearings 28. The screw structure of the present embodiment is applied between the ring nut 30 and the fixed housing 23, and the ring nut 30 is attached to the fixed housing 23 in a state in which rotation with respect to the fixed housing 23 is restricted. In the present embodiment, the ring nut 30 corresponds to the nut described in the present invention, and the stationary housing 23 corresponds to the shaft member described in the present invention.

Fig. 2 diagrammatically shows a cross section of the periphery of the ring nut 30 mounted to the stationary housing 23. The ring nut 30 has a first threaded portion 30A functioning as a female threaded portion provided on an inner peripheral surface thereof, and a second threaded portion 23A functioning as a male threaded portion provided on an outer peripheral surface of the stationary housing 23. The ring nut 30 is attached to the fixed housing 23 by engaging the first screw portion 30A with the second screw portion 23A of the fixed housing 23.

The two bearings 28 are fitted to the fixed housing 23 from one side (right side in fig. 1 and 2) in the axial direction of the fixed housing 23, and the bearing 28 on the other side (left side in fig. 1 and 2) in the axial direction is in contact with a stepped surface formed in the fixed housing 23 in the axial direction, and the bearing 28 on one side in the axial direction is in contact with the bearing 28 on the other side in the axial direction via a spacer. Thereby, the two bearings 28 are positioned at predetermined positions on the stationary housing 23. Here, the ring nut 30 is fastened to the second screw portion 23A of the fixed housing 23 so as to press the bearing 28 toward the other side in the axial direction, so that the axial movement of the bearing 28 is restricted.

The ring nut 30 of the present embodiment is formed with a rotation-restricting operation screw hole 31, and the rotation-restricting operation screw hole 31 extends in the axial direction and has a female screw portion 31A, and the rotation-restricting operation screw hole 31 is engaged with a male screw member 40 formed in a tapered shape as a whole of the outer peripheral surface. Specifically, the rotation-restricting operation screw hole 31 penetrates the ring nut 30 in the axial direction, and has a female screw portion 31A in a part of the inner peripheral surface, and the female screw portion 31A extends from an end portion of the inner peripheral surface on the side of the bearing 28 (the other side in the axial direction) toward the side opposite to the side of the bearing 28 (the one side in the axial direction). The female screw portion 31A is a tapered female screw, and is formed so as to taper toward a side away from the bearing 28 (axial side).

On the other hand, the male screw member 40 is a so-called tapered screw having a truncated cone-shaped outer diameter, and has a tapered male screw engaged with the female screw portion 31A on its outer peripheral surface. The male screw member 40 is formed with a hexagonal hole 40A extending from the large diameter side toward the small diameter side along the central axis thereof, and a through hole 40B communicating with the hexagonal hole 40A and penetrating the small diameter side end portion. By rotating a tool (a hexagonal wrench or the like) inserted into the hexagonal hole 40A through the through hole 40B, the male screw member 40 can be fastened to the rotation restricting operation screw hole 31, and the male screw member 40 can be detached from the rotation restricting operation screw hole 31.

In the present embodiment, the contact portion 101 is formed by a portion of the first screw portion 30A at the inner peripheral surface of the ring nut 30 that is located radially inward of the rotation restricting operation screw hole 31, that is, a portion located radially inward of a region where the male screw member 40 is movable (a region where the female screw portion 31A is formed) at the rotation restricting operation screw hole 31, and the contact portion 101 is deformed in the radial direction by applying a radial force to the contact portion 101. By applying a force radially inward from the male screw member 40 to the contact portion 101 in response to tightening of the male screw member 40 to the rotation restricting operation screw hole 31, the contact portion 101 is deformed toward the receiving portion 102 provided in the second screw portion 23A of the fixed housing 23.

By bringing the contact portion 101 and the receiving portion 102 into contact with each other, friction between the ring nut 30 and the fixed housing 23 increases, and rotation of the ring nut 30 relative to the fixed housing 23 is restricted. The contact portion 101 and the receiving portion 102 may be formed only one or a plurality of in the circumferential direction. Although not shown, in the present embodiment, a plurality of sets of the contact portion 101 and the receiving portion 102 are provided along the circumferential direction.

Fig. 3 is an enlarged view of a main portion of fig. 2, and is a view for explaining a contact state between the contact portion 101 and the receiving portion 102. As shown in fig. 3, when the male screw member 40 is fastened to the rotation limiting operation screw hole 31 toward one side in the axial direction (right side in fig. 3), the male screw member 40 applies a force toward the fixed housing 23 side, and the rotation limiting operation screw hole 31 gradually expands in diameter as the fastening proceeds. As a result, the contact portion 101 deforms toward the receiving portion 102 provided in the second screw portion 23A of the fixed housing 23 as indicated by arrow α in the figure.

In the present embodiment, the externally threaded member 40 is fastened until the contact portion 101 is plastically deformed to be in contact with the receiving portion 102. When the contact portion 101 comes into contact with the receiving portion 102, the first screw portion 30A formed on the contact portion 101 comes into contact with the second screw portion 23A formed on the receiving portion 102 in the axial direction, and rotation of the ring nut 30 with respect to the fixed housing 23 is restricted.

As is clear from fig. 3, the receiving portion 102 is formed as a relief portion, which is a portion of the second screw portion 23A of the fixed housing 23, and whose screw thread is lower than that of the other portion. In this example, the thread of the threaded portion constituting the receiving portion 102 is higher than the bottoms of the thread grooves of the other portions. By bringing the contact portion 101 into contact with the receiving portion 102 lowered from the periphery as described above, the contact portion 101 is prevented from excessively biting into the receiving portion 102.

Next, the operation of the present embodiment will be described.

When the ring nut 30 is attached to the fixed housing 23, first, the two bearings 28 are fitted to the fixed housing 23, and then, the ring nut 30 is engaged with the second screw portion 23A of the fixed housing 23, so that the ring nut 30 is brought into contact with the bearings 28. At this time, the rotation-restricting operation screw hole 31 of the ring nut 30 is engaged with the male screw member 40, but the male screw member 40 is kept in an initial state in which the rotation-restricting operation screw hole 31 is not expanded in diameter.

Next, by tightening the male screw member 40 toward one side in the axial direction (right side in fig. 3), a force toward the fixed housing 23 side is applied from the male screw member 40 to the rotation restricting operation screw hole 31, and the rotation restricting operation screw hole 31 is enlarged in diameter. In the present embodiment, the externally threaded member 40 is fastened until the contact portion 101 is plastically deformed to be in contact with the receiving portion 102. Further, since the contact portion 101 is engaged with, that is, brought into contact with, the receiving portion 102, the first screw portion 30A formed on the contact portion 101 is brought into contact with the second screw portion 23A formed on the receiving portion 102 in the axial direction, and the rotation of the ring nut 30 with respect to the fixed housing 23 is restricted. That is, the relative rotation between the ring nut 30 and the stationary housing 23 is restricted. Accordingly, the axial position of the ring nut 30 is maintained, whereby the axial movement of the bearing 28 can be reliably regulated.

When the ring nut 30 is removed, the male screw member 40 is first loosened to the other side in the axial direction (left side in fig. 3) to the initial state described above, for example, to release the force in the radial direction acting on the contact portion 101 due to the engagement between the contact portion 101 and the receiving portion 102, that is, the contact. Here, the contact portion 101 is plastically deformed, but a gap is generated between the contact portion 101 and the loosened externally threaded member 40, and the contact portion is easily deformed radially outward.

Next, the ring nut 30 is loosened, and at this time, the contact portion 101 moves on the second screw portion 23A of the fixed housing 23 with the movement of one side in the axial direction of the ring nut 30, and deforms radially outward according to the movement. After that, the contact portion 101 is moved in the second screw portion 23A without being obstructed, that is, the ring nut 30 is detached from the fixed housing 23 in a state in which the relative rotation between the ring nut 30 and the fixed housing 23 is allowed. That is, in the present embodiment, when the ring nut 30 is removed by releasing the radial force acting on the contact portion 101 due to the contact between the contact portion 101 and the receiving portion 102, the ring nut 30 can be removed so that the contact portion 101 deformed in the radial direction is pushed back by the first screw portion 30A on the receiving portion 102 side and then moves to the first screw portion 30A on the receiving portion 102 side.

As described above, in the screw structure of the present embodiment, when the ring nut 30 is moved in the axial direction after the contact state between the contact portion 101 and the receiving portion 102 is released, damage to the screw portions of the ring nut 30 and the fixed housing 23 due to the contact portion 101 and the receiving portion 102 can be eliminated. Thus, even when the ring nut 30, which is restricted from rotating with respect to the fixed housing 23, is removed, the ring nut 30 can be reattached to the fixed housing 23 in a rotation-restricted state without replacing the fixed housing 23 and the ring nut 30.

In the present embodiment, the contact portion 101 is formed by a part of the ring nut 30, so that the number of components used for the rotation restricting structure can be suppressed.

The receiving portion 102 is formed as a relief portion which is a part of the second screw portion 23A of the fixed housing 23 and has a lower thread than the other part. This can prevent the receiving portion 102 from being excessively deformed by the contact portion 101, and can reliably prevent damage to the component (in this example, the ring nut 30) on the side where the contact portion 101 is provided, particularly, due to deformation of the receiving portion 102 when the ring nut 30 is detached or attached. As a result, the ring nut 30 and the stationary housing 23 can be repeatedly used for a long period of time. Further, since the receiving portion 102 is a part of the second screw portion 23A and can be formed together with other screw regions by screw cutting, the rotation restriction structure can be easily manufactured.

(embodiment 2)

Next, embodiment 2 will be described. Among the constituent parts of the present embodiment, the same constituent parts as those of embodiment 1 are denoted by the same reference numerals, and description thereof is omitted. Fig. 4 is a view showing a screw structure of embodiment 2, and schematically shows a cross section of the periphery of the ring nut 30 attached to the stationary housing 23.

As shown in fig. 4, the ring nut 30 of the present embodiment has a screw hole 31 for rotation restriction operation: a tapered hole portion 31B as a non-threaded portion formed in a part of the inner peripheral surface so as to extend from an end portion of the inner peripheral surface on the bearing 28 side (the other side in the axial direction) toward the opposite side (the one side in the axial direction) from the bearing 28 side; and a female screw portion 31A penetrating from the tapered hole portion 31B toward the opposite side to the bearing 28 side. The tapered hole portion 31B is formed so as to taper toward the side opposite to the bearing 28 side, and the female screw portion 31A extends in the axial direction from the small diameter side end portion of the tapered hole portion 31B.

The externally threaded member 40 engaged with the rotation restricting operation threaded hole 31 has: a taper portion 41 inserted into the inside of the taper hole portion 31B; and a threaded rod portion 42 protruding from the tapered portion 41 and engaged with the female screw portion 31A of the screw hole 31 for rotation restriction operation. The threaded rod portion 42 protrudes from the ring nut 30, and a fastening nut 43 is mounted on the protruding portion. In the illustrated example, a washer is disposed between the fastening nut 43 and the ring nut 30.

The contact portion 101 is formed by a portion located radially inward of the rotation-restricting operation screw hole 31 and located radially inward of a region where the tapered portion 41 is movable at the rotation-restricting operation screw hole 31 (a region where the tapered hole portion 31B is formed) of the first screw portion 30A at the inner peripheral surface of the ring nut 30.

In the present embodiment, the fastening nut 43 is fastened to the bearing 28 side, and the externally threaded member 40 is fastened to the side away from the bearing 28. At this time, the tapered portion 41 of the male screw member 40 applies a force toward the fixed housing 23 side, and the rotation restricting operation screw hole 31 gradually expands in diameter as tightening proceeds. Thereby, the contact portion 101 is deformed toward the receiving portion 102 provided in the second screw portion 23A of the fixed housing 23. Thus, the same effects as those of embodiment 1 can be obtained.

(embodiment 3)

Next, embodiment 3 will be described. Among the constituent parts of the present embodiment, constituent parts similar to those of embodiment 1 and embodiment 2 are denoted by the same reference numerals, and description thereof is omitted. Fig. 5 and 6 are diagrams showing the screw structure of embodiment 3, and schematically show a cross section of the periphery of the ring nut 30 attached to the stationary housing 23.

As shown in fig. 5, the ring nut 30 is formed with a screw hole 31 for rotation restriction operation, and a communication hole 34 penetrating from the screw hole 31 for rotation restriction operation in the radial direction toward the fixed housing 23 is formed. Further, the male screw member 40 having the tapered portion 41 at the tip thereof is engaged with the rotation restricting operation screw hole 31, and the tapered portion 41 is tapered toward the screw-in side.

The screwed-in side of the externally threaded member 40 is on the bearing 28 side (the other side in the axial direction), and the side on which the ring nut 30 is loosened and the side on which the externally threaded member 40 is loosened are in the same direction. An operation hole 44 into which a tool is inserted is formed at an end of the male screw member 40 on the opposite side of the tapered portion 41, and the male screw member 40 can be screwed into or loosened from the rotation-restricting operation screw hole 31 by rotating the tool inserted into the operation hole 44.

In addition, the externally threaded member 40 has: a taper portion 41; a threaded rod portion 42 that engages with the female screw portion 31A of the screw hole 31 for rotation restriction operation; and a cylindrical non-threaded portion 45 located between the tapered portion 41 and the threaded rod portion 42.

The ring nut 30 is provided with: a first screw portion 30A on the side where the male screw member 40 is loosened; and a non-threaded portion 30B which is positioned on the side into which the male screw member 40 is screwed and has a larger diameter than the thread of the first threaded portion 30A, and a communication hole 34 is formed in the non-threaded portion 30B.

On the other hand, as shown in fig. 6, the contact portion 101 is formed of a moving body arranged in the communication hole 34 in the following manner: in a state before the contact with the tapered portion 41 of the male screw member 40, the movable body can be retracted to a position not interfering with the top of the thread of the second screw portion 23A of the fixed housing 23, and as shown in fig. 5, the movable body moves toward the fixed housing 23 due to the tightening of the male screw member 40. The contact portion 101 is formed of a steel ball, but the material thereof is not particularly limited.

In addition, as shown in fig. 5, in the present embodiment, the male screw member 40 is fastened until the contact portion 101 reaches the outer peripheral surface of the non-threaded portion 30B beyond the tapered portion 41.

In the screw structure of the present embodiment, by loosening the male screw member 40, as shown in fig. 6, the radial force acting on the contact portion 101 due to the contact between the contact portion 101 and the receiving portion 102 is released. Then, when the ring nut 30 is removed, after the contact portion 101 that has moved toward the fixed housing 23 side in the radial direction is pushed back by the second screw portion 23A on the receiving portion 102 side, the ring nut 30 can be removed so as to move on the second screw portion 23A on the receiving portion 102 side or so as not to interfere with the second screw portion 23A.

Accordingly, when the ring nut 30 is axially moved after the contact state between the contact portion 101 and the receiving portion 102 is released, damage to the respective screw portions of the ring nut 30 and the fixed housing 23 due to the contact portion 101 and the receiving portion 102 can be eliminated. In particular, since the contact portion 101 can be retracted from the top of the thread of the second threaded portion 23A on the receiving portion 102 side when the fastening of the male screw member 40 is loosened, the second threaded portion 23A on the receiving portion 102 side does not interfere with the second threaded portion 23A, and therefore, in the present embodiment, damage to the second threaded portion 23A on the receiving portion 102 side due to the contact portion 101 can be reliably suppressed when the ring nut 30 is removed.

Even if the second threaded portion 23A on the receiving portion 102 side is deformed by the contact portion 101, the first threaded portion 30A on the contact portion 101 side does not pass through the receiving portion 102 when the ring nut 30 is removed, and the first threaded portion 30A on the side where the contact portion 101 is provided is not damaged by the deformed portion on the receiving portion 102 side, so that the contact portion 101 is retracted. Therefore, when the ring nut 30 is detached, damage to both the ring nut 30 and the fixed housing 23 can be reliably suppressed, and the ring nut 30 and the fixed housing 23 can be repeatedly used for a long period of time.

(embodiment 4)

Next, embodiment 4 will be described. Among the constituent parts of the present embodiment, constituent parts similar to those of embodiment 1 to embodiment 3 are denoted by the same reference numerals, and description thereof is omitted. Fig. 7 is a view showing a screw structure of embodiment 4, and schematically shows a cross section of the periphery of the ring nut 30 attached to the stationary housing 23.

As shown in fig. 7, the externally threaded member 40 in the present embodiment has: a taper portion 41; a threaded rod portion 42 that engages with the female screw portion 31A of the screw hole 31 for rotation restriction operation; a cylindrical non-threaded portion 45 located between the tapered portion 41 and the threaded rod portion 42; and a head 46 that is joined to an end of the threaded rod portion 42 on the side opposite to the tapered portion 41 side and protrudes from the threaded rod portion 42. An operation hole 44 into which a tool is inserted is formed in the head 46. Other components are the same as those in embodiment 3. In this embodiment, the same effects as those of embodiment 3 can be obtained.

(embodiment 5)

Next, embodiment 5 will be described. Among the constituent parts of the present embodiment, constituent parts similar to those of embodiment 1 to embodiment 4 are denoted by the same reference numerals, and description thereof is omitted. Fig. 8 is a view showing the screw structure of embodiment 5, and schematically shows a cross section of the periphery of the ring nut 30 attached to the stationary housing 23.

As shown in fig. 8, the externally threaded member 40 in the present embodiment has: a taper portion 41; a threaded rod portion 42 that engages with the female screw portion 31A of the screw hole 31 for rotation restriction operation; and a head 46 that is joined to an end of the threaded rod portion 42 on the side opposite to the tapered portion 41 side and protrudes from the threaded rod portion 42 without the unthreaded portion 45. Other components are the same as those in embodiment 4. In this embodiment, the same effects as those of embodiment 4 can be obtained.

(embodiment 6)

Next, embodiment 6 will be described. Among the constituent parts of the present embodiment, constituent parts similar to those of embodiment 1 to embodiment 5 are denoted by the same reference numerals, and description thereof is omitted. Fig. 9 is a view showing a screw structure of embodiment 6, and schematically shows a cross section of the periphery of ring nut 30 attached to stationary housing 23.

As shown in fig. 9, in the present embodiment, a rotation restriction operation screw hole 61 is formed in an axial end surface 23E (more specifically, one end surface in the axial direction) of the fixed housing 23, and the male screw member 40 is engaged with the rotation restriction operation screw hole 61. The rotation restricting operation screw hole 61 extends in the axial direction and is formed on the outer peripheral side of the axial end surface 23E of the fixed housing 23.

The contact portion 101 is independent of the externally threaded member 40, and is formed of a movable body that can be moved in the radial direction toward the side of the ring nut 30 by screwing in the externally threaded member 40, and can be retracted to a position that does not interfere with the top of the thread of the first threaded portion 30A of the ring nut 30 in a state before being in contact with the externally threaded member 40. The contact portion 101 is formed of steel balls as in embodiment 3, but the material thereof is not particularly limited.

More specifically, the fixed housing 23 is formed with a communication hole 64 penetrating from the rotation restriction operation screw hole 61 toward the ring nut 30 in the radial direction, and the contact portion 101 is disposed in the communication hole 64. The male screw member 40 has the same structure as in embodiment 3, and includes: a tapered portion 41 tapered on the screwed-in side; and a threaded rod portion 42 that engages with the female screw portion of the threaded hole 61 for rotation restriction operation. In addition, the side on which the ring nut 30 is loosened and the side on which the externally threaded member 40 is loosened are in the same direction.

The outer peripheral surface of the stationary case 23 is provided with: a second screw portion 23A which is separated from an axial end surface 23E of the stationary housing and is located on the side into which the male screw member 40 is screwed; and a non-threaded portion 23F located between the axial end surface 23E and the second threaded portion 23A, the diameter of which is smaller than the diameter of the thread of the second threaded portion 23A. Here, the communication hole 64 and the contact portion 101 are provided in the non-threaded portion 23F.

In the screw structure of the present embodiment, by screwing the male screw member 40, the contact portion 101 is moved from the fixed housing 23 side toward the ring nut 30 side in the radial direction, and the contact portion 101 can be brought into contact with the receiving portion 102 of the first screw portion 30A of the ring nut 30. Thereby, the rotation of the ring nut 30 is restricted. Then, when the ring nut 30 is detached by releasing the radial force acting on the contact portion 101 due to the contact between the contact portion 101 and the receiving portion 102, the contact portion 101 can be retracted to a position where it does not interfere with the top of the thread of the first thread portion 30A of the ring nut 30. Thus, the ring nut 30 can be moved so that the contact portion 101 does not interfere with the receiving portion 102 and the contact portion 101 and the receiving portion 102 do not interfere with the threaded portion on the other side.

In the above, when the ring nut 30 is moved in the axial direction after the contact state between the contact portion 101 and the receiving portion 102 is released, damage to the respective screw portions of the ring nut 30 and the fixed housing 23 due to the contact portion 101 and the receiving portion 102 can be eliminated. Therefore, even when the ring nut 30 which is restricted from rotating with respect to the fixed housing 23 is removed, the ring nut 30 can be reinstalled in a restricted rotation state with respect to the fixed housing 23 without replacing the fixed housing 23 and the ring nut 30.

Even if the receiving portion 102 is deformed by the contact portion 101 in particular, the receiving portion 102 does not pass through the second threaded portion 23A on the side of the contact portion 101 when the ring nut 30 is removed, and the second threaded portion 23A on the side where the contact portion 101 is provided is not damaged by the deformed portion on the side of the receiving portion 102, so that the contact portion 101 can be retracted. Therefore, damage to both the ring nut 30 and the fixed housing 23 can be reliably suppressed when the ring nut 30 is detached, and the ring nut 30 and the fixed housing 23 can be repeatedly used for a long period of time.

(embodiment 7)

Next, embodiment 7 will be described. Among the constituent parts of the present embodiment, constituent parts similar to those of embodiment 1 to embodiment 6 are denoted by the same reference numerals, and description thereof is omitted. Fig. 10 is a view showing a screw structure of embodiment 7, and schematically shows a cross section of the periphery of the ring nut 30 attached to the stationary housing 23.

As shown in fig. 10, in the present embodiment, a screw hole 61 for rotation restriction operation is formed in an axial end surface 23E of the fixed housing 23, and the screw hole 61 for rotation restriction operation is engaged with the male screw member 40. The rotation restricting operation screw hole 61 extends from the axial end surface 23E toward the obliquely outer side. In the present embodiment, the contact portion 101 is formed by the tip end of the externally threaded member 40, and the contact portion 101 is screwed so as to be moved so as to protrude toward the ring nut 30 side in the radial direction. In this embodiment, the same effects as those of embodiment 6 can be obtained.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various modifications may be made to the above embodiments.

Claims

1. A thread construction, wherein,

the screw structure is provided with:

a nut having a first screw portion on an inner circumferential surface thereof, the nut being deformed or moved by a radial force applied thereto; and

a shaft member having a second screw portion on an outer peripheral surface thereof, the second screw portion being engaged with the first screw portion of the nut, the shaft member being brought into contact with the deformed or moved nut to restrict relative rotation between the shaft member and the nut, and the shaft member and the nut being allowed to relatively rotate after the force is released,

the nut includes a contact portion which is deformed or moved by the force applied thereto,

the shaft member includes a receiving portion that contacts the deformed or moved contact portion,

after the force is released, the contact portion does not interfere with the receiving portion, and the contact portion and the receiving portion do not interfere with the threaded portion on the opposite side,

the shaft member is in contact with the deformed nut at a portion of the second threaded portion having a lower thread than the other portion.

2. A hydraulic drive device, wherein,

the hydraulic drive device is provided with:

a nut having a first screw portion on an inner circumferential surface thereof, the nut being deformed or moved by a radial force applied thereto;

a hydraulic motor having a cylindrical fixed housing, the cylindrical fixed housing having a second screw portion on an outer circumferential surface thereof, the second screw portion being engaged with the first screw portion of the nut, the hydraulic motor being configured to restrict relative rotation between the cylindrical fixed housing and the nut by bringing the cylindrical fixed housing into contact with the deformed or moved nut, and to permit relative rotation between the cylindrical fixed housing and the nut after the force is released; and

a rotary housing provided on an outer peripheral surface of the fixed housing, supported by the fixed housing so as to be rotatable with respect to the fixed housing via a bearing which is restrained by the nut by axial movement,

the fixed housing is provided with a receiving part which is contacted with the deformed or moved contact part,

the fixing housing is in contact with the deformed nut at a portion of the second threaded portion having a lower thread than the other portion.