JP5573620B2 - Ball screw device - Google Patents

Description

  The present invention relates to a ball screw device, and is particularly suitable for a ball screw device that is used by attaching a seal member to an end portion in the axial direction of a ball screw nut.

  The ball screw device has a male ball screw groove on the ball screw shaft and a female ball screw groove on the ball screw nut. A ball (steel ball) is interposed between the female and male ball screw grooves, and the steel ball rolls smoothly. Rotation-linear motion is possible. If foreign matter intervenes between the ball and the male and female ball screw grooves, smooth rotation-linear motion cannot be secured. For example, a seal member is attached to the axial end of the ball screw nut, and the seal lip of the seal member is placed inside the male ball screw groove. There is also a ball screw device that contacts the outer shape of the ball screw shaft and prevents foreign objects from entering. In the following Patent Document 1, a ball screw device is described in which two or more seal members are attached to the end of the ball screw nut in the axial direction. Further, in Patent Document 1, for example, when two thin plate-like seal members are attached in the axial direction, the ball screw grooves of the ball screw shaft at the seal lip position of each seal member are out of phase. It is also described that each seal member is fixed to a ball screw nut in accordance with the phase.

JP 2002-364726 A

  By the way, in the ball screw device described in Patent Document 1, phase adjustment in the rotational direction of the seal member itself with respect to the ball screw shaft or the ball screw nut cannot be performed. For example, when a seal member is attached to a predetermined end surface in the axial direction of the ball screw nut, the phase between the seal lip of the seal member attached to the predetermined end surface in the axial direction of the ball screw nut and the ball screw groove of the ball screw shaft is constant by design. In some cases, the phases of both may be shifted due to manufacturing errors. In such a case, in order to obtain good contact between the outer shape of the ball screw shaft and the seal lip of the seal member, it is necessary to adjust the phase of the seal member itself with respect to the ball screw shaft or the ball screw nut.

  The phase adjustment in the rotation direction of the seal member itself may be achieved by, for example, making the insertion hole through which the screw portion of the screw member for attaching the seal member to the attachment object is elongated (lengthened) in the rotation direction. However, when two or more seal members are attached to the end of the ball screw nut in the axial direction, if the screw member insertion holes of all the seal members are simply elongated, the phases of all the seal members must be individually adjusted. In addition to being troublesome, it is difficult to determine whether or not each seal member reliably exhibits a sealing effect. For example, when mounting two thin plate-like seal members, if the seal member that contacts the ball screw nut is the inner seal member, and the seal member closest to the inner seal member is the outer seal member, while confirming the sealing effect of the inner seal member After adjusting the phase of the inner seal member, even if an attempt is made to adjust the phase of the outer seal member while confirming the sealing effect of the outer seal member, whether the seal effect is the sealing effect of the outer seal member or not. Cannot determine whether it is due to the sealing effect.

  The present invention has been made paying attention to the above-described problems, and even when two or more seal members are attached to the end of the ball screw nut in the axial direction, the seal member closest to the ball screw nut It is an object of the present invention to provide a ball screw device in which the sealing effect of each sealing member can be obtained with certainty only by adjusting the phase.

  In order to solve the above-mentioned problems, in the ball screw device of the present invention, two or more seal members are attached to the axial end of the ball screw nut in the axial direction, and the seal lip of each seal member contacts the outer shape of the ball screw shaft. In the ball screw device, when the seal member closest to the ball screw nut is the inner seal member and the seal member closest to the inner seal member is the outer seal member, the predetermined position of the predetermined axial end surface of the axial end of the ball screw nut And a nut screw hole for screwing an inner screw member for fixing the inner seal member, a ball screw formed at a position facing the nut screw hole of the inner seal member and passing through the screw portion of the inner screw member and An inner insertion hole for phase adjustment that is long in the rotational direction of the screw nut or ball screw shaft, and at least the inner seal member An inner screw hole formed at a predetermined position on the side end face of the side seal member and screwed with an outer screw member for fixing the outer seal member; and formed at a position facing the inner screw hole of the outer seal member An outer insertion hole through which the screw portion of the screw member is inserted, the screw portion of the outer screw member is inserted into the outer insertion hole and the outer screw member is screwed into the inner screw hole, and the outer seal member is engaged with the inner seal member. The phase difference between the inner shape of the inner seal lip of the inner seal member and the inner shape of the outer seal lip of the outer seal member is fixed in the axial direction of the inner seal lip of the inner seal member and the outer seal lip of the outer seal member. A predetermined phase difference is set according to the distance, the number of ball screw grooves on the ball screw shaft, and the lead.

  When the outer seal member is further attached to the side opposite to the ball screw nut of the outer seal member, the outer seal member is formed at a predetermined position on the outer seal member side end surface of the outer seal member and is used for fixing the outer seal member. An outer screw hole for screwing the outer screw member, and an outer and outer insertion hole formed at a position facing the outer screw hole of the outer and outer seal member and passing through the screw portion of the outer and outer screw member. When the outer outer screw member is inserted into the outer insertion hole and the outer outer screw member is screwed into the outer screw hole to fix the outer outer seal member to the outer seal member, the outer seal lip of the outer seal member is fixed. The phase difference between the inner shape and the inner shape of the outer and outer seal lips of the outer and outer seal members is the axial distance between the outer seal lip of the outer seal member and the outer and outer seal lips of the outer and outer seal members. And it is characterized in that it has a predetermined phase difference corresponding to the number of threads and the lead of the ball screw groove of the ball screw shaft.

  Thus, according to the ball screw device of the present invention, the nut screw hole is formed at a predetermined position of the predetermined axial end surface of the axial end portion of the ball screw nut, and the inner side for phase adjustment is formed at a position facing the nut screw hole of the inner seal member. An insertion hole is formed, an inner screw hole is formed at a predetermined position on the outer seal member side end surface of the inner seal member, an outer insertion hole is formed at a position facing the inner screw hole of the outer seal member, and the outer insertion hole is formed outside. The inner shape of the inner seal lip of the inner seal member and the outer seal of the outer seal member when the screw portion of the screw member is inserted and the outer screw member is screwed into the inner screw hole and the outer seal member is fixed to the inner seal member. The phase difference between the inner shape of the lip and the axial distance between the inner seal lip of the inner seal member and the outer seal lip of the outer seal member, the number of ball screw grooves on the ball screw shaft, and the By was predetermined phase difference corresponding to the sealing effect of the sealing effect even outer seal member of the inner sealing member by simply adjusting the phase of the nearest inner seal member to the ball screw nut may be reliably obtained.

  When the outer seal member is further mounted on the side opposite to the ball screw nut of the outer seal member, an outer screw hole is formed at a predetermined position on the outer seal member side end surface of the outer seal member, and the outer screw hole of the outer seal member is formed. The outer and outer insertion holes are formed at positions facing the outer and outer insertion holes, the screw portions of the outer and outer screw members are inserted into the outer and outer insertion holes, and the outer and outer screw members are screwed into the outer screw holes and the outer and outer seal members are joined to the outer seal member. The phase difference between the inner shape of the outer seal lip of the outer seal member and the inner shape of the outer outer seal lip of the outer outer seal member is set to the outer seal lip of the outer seal member and the outer outer seal lip of the outer outer seal member. The phase of the inner seal member closest to the ball screw nut is adjusted by setting a predetermined phase difference according to the axial distance between the ball screw shaft and the number of ball screw grooves on the ball screw shaft and the lead. Sealing effect of the sealing effect outside the outer seal member of the seal effect outer seal member just inside the sealing member that can be obtained with certainty. In addition, by repeating this in sequence, even when two or more seal members are attached to the ball screw nut, the sealing effect of each seal member can be ensured only by adjusting the phase of the inner seal member closest to the ball screw nut. Is obtained.

It is a longitudinal cross-sectional view which shows one Embodiment of the ball screw apparatus of this invention. It is an axial direction arrow directional view of the axial direction end surface of the ball screw nut of the ball screw apparatus of FIG. FIG. 3 is an axial arrow view of a state in which an inner seal member is attached to an axial end surface of the ball screw nut of FIG. 2. FIG. 4 is an axial direction view of the state where the outer seal member is attached to the inner seal member of FIG. 3.

Next, an embodiment of the ball screw device of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view of the ball screw device of the present embodiment. In the figure, reference numeral 1 denotes a ball screw shaft, and reference numeral 2 denotes a ball screw nut. The ball screw shaft 1 has a male ball screw groove, the ball screw nut 2 has a female ball screw groove, and a plurality of balls 3 are formed between the male and male ball screw grooves. It is intervened. For example, when the ball screw shaft 1 is rotated while restricting the rotation of the ball screw nut 2, the ball screw nut 2 moves directly. At this time, since the ball 3 interposed between the male and female ball screw grooves rolls, a smooth rotation-linear motion is achieved.

  In the present embodiment, two (two) thin plate-like seal members 4 and 5 are attached to the right end surface of the ball screw nut 2 on the right end portion of the ball screw nut 2 in the axial direction. Among these, the seal member 4 closest to the ball screw nut 2, that is, the seal member 4 on the left side in the figure is defined as the inner seal member 4, and the seal member 5 closest to the inner seal member 4, that is, the seal member 5 in the center in the figure is outside. When the seal member 6 is further defined on the side opposite to the ball screw nut 2 of the outer seal member 5 as will be described later, the seal member 6 is defined as the outer and outer seal member 6. In this embodiment, the inner seal member 4 is fixed to the ball screw nut 2 with the inner screw member 7, the outer seal member 5 is fixed to the inner seal member 4 with the outer screw member 8, and the outer and outer seal members 6 are outer and outer. The outer seal member 5 is fixed with the screw member 9. An inner seal lip 10 is formed on the inner seal member 4, an outer seal lip 11 is formed on the outer seal member 5, and an outer outer seal lip 12 is formed on the outer outer seal member 6. All the seal lips 10 to 12 of 4 to 6 come into contact with the outer shape of the ball screw shaft 1 to generate a sealing effect.

FIG. 2 is an axial view of the nut screw hole 13 formed in the right end surface of the ball screw nut 2 shown in FIG. 1 in order to fix the inner seal member 4 to the ball screw nut 2. In the present embodiment, the nut screw holes 13 are formed at equal intervals at three locations in the upper, lower right, and lower left in FIG.
FIG. 3 is an axial arrow view of the state in which the inner screw member 7 is screwed into the nut screw hole 13 and the inner seal member 4 is fixed to the ball screw nut 2. A ball screw nut 2 or a ball screw shaft is inserted into the inner seal member 4 at a position facing the nut screw hole 13 so as to insert the screw portion of the inner screw member 7 and adjust the phase of the inner seal member 4 in the rotational direction. A total of three phase adjustment inner insertion holes 14 that are long in the direction of rotation 1 are formed. The inner seal member 4 has an inner screw hole 15 for fixing the outer seal member 5 to the inner seal member 4 at least on the end surface on the outer seal member 5 side in FIG. Is formed. The reason why the end face on the outer seal member 5 side is at least is that the inner screw hole 15 may penetrate to the end face on the ball screw nut 2 side, however, the inner screw for fixing the outer seal member 5 to the inner seal member 4. Since it is the hole 15, it is essential that the inner seal member 4 is open at the end surface on the outer seal member 5 side. In the present embodiment, the inner screw holes 15 are formed at equal intervals at three locations in the lower part of FIG.

  FIG. 4 is an axial arrow view of the state in which the outer screw member 8 is screwed into the inner screw hole 15 and the outer seal member 5 is fixed to the inner seal member 4. A total of three outer insertion holes 16 for inserting the screw portions of the outer screw member 8 are formed at positions facing the inner screw hole 15 in the outer seal member 5. The outer seal member 5 is provided with an outer through-hole 17 for accommodating the head of the inner screw member 7 or operating the inner screw member 7 at a position facing the inner screw member 7. Has been.

  In the present embodiment, when the screw portion of the outer screw member 8 is inserted into the outer insertion hole 16 and the outer screw member 8 is screwed into the inner screw hole 15 to fix the outer seal member 5 to the inner seal member 4. The phase difference between the inner shape of the inner seal lip 10 of the inner seal member 4 and the inner shape of the outer seal lip 11 of the outer seal member 5 is determined according to the phase difference between the inner seal lip 10 of the inner seal member 4 and the outer seal lip 11 of the outer seal member 5. And a predetermined phase difference corresponding to the number of the ball screw grooves of the ball screw shaft 1 and the lead. For example, if the number of ball screw grooves on the ball screw shaft 1 is 1, the lead is L, and the axial distance between the inner seal lip 10 of the inner seal member 4 and the outer seal lip 11 of the outer seal member 5 is x, the inner seal The phase difference φ between the inner shape of the inner seal lip 10 of the member 4 and the inner shape of the outer seal lip 11 of the outer seal member 5 is expressed by φ = (x / L) × 360 °.

  Thus, the inner seal member when the outer screw member 8 is inserted into the outer insertion hole 16 and the outer screw member 8 is screwed into the inner screw hole 15 to fix the outer seal member 5 to the inner seal member 4. By defining the phase difference between the inner shape of the inner seal lip 10 and the inner shape of the outer seal lip 11 of the outer seal member 5, the inner side of the inner seal member 4 closest to the ball screw nut 2 can be adjusted by adjusting the phase. The sealing effect of the seal member 4 and the sealing effect of the outer seal member 5 can be reliably obtained.

  Further, as shown by a two-dot chain line in FIG. 1, when the outer outer seal member 6 is further attached to the side opposite to the ball screw nut 2 of the outer seal member 5, a predetermined position of the end face on the outer outer seal member 6 side of the outer seal member 5. An outer screw hole is formed at a position facing the outer screw hole of the outer outer seal member 6, the screw portion of the outer outer screw member 9 is inserted into the outer outer insert hole, and the outer screw hole is inserted. When the outer and outer screw members 9 are screwed together to fix the outer and outer seal members 6 to the outer seal member 5, the inner shape of the outer seal lip 11 of the outer seal member 5 and the outer and outer seal lips 12 of the outer and outer seal member 6 are fixed. The phase difference from the inner shape of the outer seal member 5 depends on the axial distance between the outer seal lip 11 of the outer seal member 5 and the outer seal lip 12 of the outer seal member 6, the number of ball screw grooves on the ball screw shaft 1, and the lead. Localization If the difference is made, the sealing effect of the inner sealing member 4, the sealing effect of the outer sealing member 5, and the sealing effect of the outer outer sealing member 6 can be reliably obtained only by adjusting the phase of the inner sealing member 4 closest to the ball screw nut 2. It is done. Further, by repeating this in sequence, even when two or more seal members are attached to the ball screw nut 2 in a multiple manner, the seal of each seal member can be obtained by simply adjusting the phase of the inner seal member 4 closest to the ball screw nut 2. The effect is definitely obtained.

  In the above embodiment, the inner seal member 4 is directly attached to the ball screw nut 2, the outer seal member 5 is directly attached to the inner seal member 4, and the outer and outer seal member 6 is directly attached to the outer seal member 5. A member other than the seal member may be interposed between them, and for example, a holding member made of a metal thin plate material for holding the seal member may be interposed. In any case, the seal member closest to the ball screw nut 2 is the inner seal member 4, the seal member closest to the inner seal member 4 is the outer seal member 5, and the seal member attached to the opposite side of the outer seal member 5 from the ball screw nut 2. If the outer and outer seal members 6 are used, the present invention can be applied to all seal members.

1 is a ball screw shaft 2 is a ball screw nut 3 is a ball 4 is an inner seal member 5 is an outer seal member 6 is an outer outer seal member 7 is an inner screw member 8 is an outer screw member 9 is an outer outer screw member 10 is an inner seal lip 11 The outer seal lip 12 is an outer outer seal lip 13 is a nut screw hole 14 is an inner insertion hole for phase adjustment 15 is an inner screw hole 16 is an outer insertion hole 17 is an outer through hole

Claims (3)

  A ball screw device in which two or more seal members are mounted in the axial direction at the end of the ball screw nut in the axial direction, and the seal lip of each seal member is in contact with the outer shape of the ball screw shaft. When the seal member closest to the seal member and the inner seal member is an outer seal member, the inner screw member is formed at a predetermined position on a predetermined axial end surface of the axial end portion of the ball screw nut and is used to fix the inner seal member A nut screw hole to be screwed, and an inner insertion for phase adjustment which is formed at a position facing the nut screw hole of the inner seal member and is inserted through the screw portion of the inner screw member and is long in the rotation direction of the ball screw nut or the ball screw shaft And at least a predetermined position on the outer seal member side end surface of the inner seal member and the outer seal member. An inner screw hole for screwing an outer screw member for fixing the member, and an outer insertion hole formed at a position facing the inner screw hole of the outer seal member and passing through the screw portion of the outer screw member. The inner seal lip of the inner seal member when the outer screw member is inserted into the outer insertion hole and the outer screw member is screwed into the inner screw hole to fix the outer seal member to the inner seal member. The phase difference between the shape and the inner shape of the outer seal lip of the outer seal member is the axial distance between the inner seal lip of the inner seal member and the outer seal lip of the outer seal member, the number of ball screw grooves on the ball screw shaft, and the lead. A ball screw device having a predetermined phase difference according to   When the outer and outer seal members are further attached to the side opposite to the ball screw nut of the outer seal member, the outer and outer screws are formed at a predetermined position on at least the outer outer seal member side end surface of the outer seal member and fix the outer and outer seal members. An outer screw hole for screwing the member, and an outer outer insertion hole formed at a position facing the outer screw hole of the outer outer seal member and passing through the screw portion of the outer outer screw member. The inner shape of the outer seal lip of the outer seal member when the screw portion of the outer outer screw member is inserted into the hole and the outer outer screw member is screwed into the outer screw hole and the outer outer seal member is fixed to the outer seal member. The axial difference between the outer seal lip of the outer seal member and the outer outer seal lip of the outer and outer seal member Ball screw device according to claim 1, characterized in that a predetermined phase difference corresponding to the number of threads and the lead of the ball screw groove of Runeji axis. The ball screw device according to claim 2, wherein the sealing performance is improved with respect to three sealing lips only by adjusting the phase of the inner sealing member.

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