JP4736227B2 - Backlash prevention structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backlash prevention structure for fixing a long member such as an iron pipe to a housing so as to be slidable without backlash.
[0002]
[Prior art]
Conventionally, after inserting an iron pipe (including solid) with a circular or square cross-section into a through hole of a metal housing and fitting it in a state with play, this iron pipe is free from play with respect to the housing. A backlash prevention structure having a configuration that can slide in the axial direction in a state is considered.
[0003]
For example, as shown in FIG. 7 , in order to eliminate the play of the iron pipe 2 fitted in the housing 20 made of aluminum or the like, the pad 4 and the dish are provided in the screw hole 20a provided in the housing 20 and formed with a thread. After inserting the spring 5, as shown in FIG. 8 , there is a method of screwing the screw 7, pressing the iron pipe 2 through the pad 4 and the disc spring 5, and fixing the screw 7 with the lock nut 11. At this time, the force at the tip of the screw 7 is dispersed by the pad 4 so that the entire contact surface of the pad 4 has a constant pressure.
[0004]
[Problems to be solved by the invention]
However, the conventional anti-rare structure is not particularly problematic at room temperature, but at a low temperature, the thermal expansion coefficient differs between the aluminum of the housing 20 and the iron pipe 2 on the slide side, so that it is smaller than the reduction amount of the inner diameter of the housing 20. The amount of reduction in the outer diameter of the iron pipe 2 is small, and the gap B that is the distance between the housing 20 and the iron pipe 2 becomes smaller. For this reason, the tightening degree of the screw 7 with respect to the iron pipe 2 becomes excessive, and there is a problem that the iron pipe 2 becomes difficult or impossible to slide with respect to the housing 20.
On the other hand, when the temperature becomes high, a phenomenon opposite to that at the low temperature occurs, the gap B becomes larger, the tightening degree of the screw 7 with respect to the iron pipe 2 becomes too small, and the play of the iron pipe 2 becomes larger. There was a problem.
[0005]
The present invention improves the inconvenience of the conventional example, and does not become slidable even when the temperature is low or high, and conversely, the play does not become excessively large. It is an object of the present invention to provide a backlash prevention structure with a simple configuration capable of holding pressure.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a rattle prevention structure of the present invention comprises a tubular or rod-like long member made of a first metal and a second metal having a thermal expansion coefficient different from that of the first metal. A housing for fitting the length member, a screw for tightening the long member to the housing so as to be slidable in the lengthwise axial direction, and the second metal, and having a substantially rectangular cross-sectional shape in the longitudinal direction. A pressing member having a length equal to or substantially equal to the outer diameter of the elongate member, and a communication hole provided in the housing so that one end side in the longitudinal direction of the pressing member can press the elongate member; It consists of the first metal, holds the pressing member slidably in its longitudinal direction, has a screw hole for tightening with the screw and pressing the other end side in the longitudinal direction of the pressing member, The pressing member is the communication hole It is characterized in that it comprises a second housing fixed to a predetermined position of available housing.
In the play preventing structure according to claim 2, the second housing is fixed to the housing such that the longitudinal direction of the pressing member is substantially parallel to the sliding direction of the long member, and A pressing force transmission member is provided that transmits the pressing force in the longitudinal direction of the pressing member to the long member instead of the pressing force in a direction substantially orthogonal thereto .
In the play preventing structure according to claim 3, the first metal is iron.
Furthermore, in the play preventing structure according to claim 4, the second metal is aluminum.
[0007]
With the above configuration, the amount of change in the outer diameter of the long member differs at low or high temperatures compared to the amount of change in the inner diameter of the housing. And the second housing also changes in the screw hole axial direction. The total amount of change in the outer diameter of the long member and the change in the longitudinal direction of the pressing member due to this temperature is substantially equal to the sum of the change in the screw hole axial direction of the second housing and the change in the housing inner diameter. As a result of canceling each other, the pressing force of the pressing member against the long member is kept substantially unchanged from that at normal temperature.
[0008]
Therefore, when the housing inner diameter is reduced at a low temperature, the long member is not excessively pressed by the pressing member so that the long member cannot be slid. At a high temperature, the housing inner diameter is increased. Since the pressing member also extends in the pressing direction at the same time, the pressing on the long member does not loosen and the backlash of the long member does not increase. In any case, the pressing force of the pressing member against the long member is maintained in an appropriate state that allows the sliding without affecting the temperature.
[0009]
Further, the second housing is fixed to the housing so that the longitudinal direction of the pressing member is substantially parallel to the sliding direction of the long member, and a pressing force transmitting member for transmitting the pressing force is provided, thereby providing the second housing. Since it does not protrude, space can be used effectively.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
1 is a cross-sectional view of a backlash preventing structure showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a backlash preventing structure showing the second embodiment, and FIG. 3 is a backlash preventing structure showing the third embodiment. FIG. 4 is a cross-sectional view of the backlash preventing structure showing the fourth embodiment, and FIG. 5 is a cross-sectional view of the backlash preventing structure showing the fifth embodiment.
[0011]
FIG. 1 shows a first embodiment of the play preventing structure. In the figure, an iron pipe 2 which is a long member made of iron (first metal) is fitted in an aluminum housing 1 made of aluminum (second metal). On the other hand, a screw hole 3a and a through hole 3b continuous therewith are provided, and an iron housing 3 which is a second housing made of iron (first metal) and having a cylindrical shape is connected to an aluminum housing 1 through a communication hole 1a. Are fixed to the aluminum housing 1 so that the through-holes 3b communicate with each other, that is, so that the central axes of the holes are concentric. A pad 4, a disc spring 5, and a cylindrical pressing member 6 made of aluminum (second metal) are sequentially inserted into the communication hole 1 a of the aluminum housing 1 and the continuous through hole 3 b, and the screw hole 3 a. These are housed in pressure contact by tightening with screws 7 that are screwed together. By tightening the screw 7, the lower end portion of the pressing member 6 presses the outer peripheral surface of the iron pipe 2 via the pad 4 and the disc spring 5, and the screw 7 is fixed to the iron housing 3 by a lock nut 11. . The length of the pressing member 6 in the longitudinal direction is set equal to or substantially equal to the outer diameter A of the iron pipe 2.
In this embodiment, the pressing member 6 has a cylindrical shape. However, the pressing member 6 is not limited to this, and may have a cross-sectional shape in the longitudinal direction that is substantially rectangular. In this embodiment, the case of the iron pipe 2 is considered as the long member, but other members can be applied as long as they are tubular or rod-shaped members.
[0012]
In this configuration, since the thermal expansion coefficient is different between the aluminum housing 1 and the slide-side iron pipe 2, the amount by which the outer diameter A of the iron pipe 2 is reduced compared to the amount by which the inner diameter of the aluminum housing 1 is reduced at low temperatures. Is slight. However, at the same time, the pressing member 6 is also reduced in the axial direction of the screw hole 3a, and the iron housing 3 is also slightly reduced in the axial direction of the screw hole 3a. Thus, the total dimensional change of the iron pipe 2 and the pressing member 6 due to temperature is substantially equal to the total dimensional change of the iron housing 3 and the aluminum housing 1.
[0013]
For example, the change in the pressing direction of each member (arrow C direction, see FIG. 1) at the contact portion of the pressing member 6 with the iron pipe 2 via the pad 4 is (−), and the change in the opposite direction is (+ ) And a simplified numerical value, the amount of reduction of the outer diameter A of the iron pipe 2 at a low temperature is −2, and the amount of reduction of the pressing member 6 is +3. It is considered that the amount of reduction is +2, and the amount of reduction of the inner diameter of the aluminum housing 1 is -3. Since the total change amount of the iron pipe 2 and the pressing member 6 is +1, and the total change amount of the iron housing 3 and the aluminum housing 1 is −1, 1-1 = 0. The total change amount of the member is 0, and the change amount is canceled out. The same effect can be considered even at high temperatures.
[0014]
For this reason, at a low temperature, as the inner diameter of the aluminum housing 1 is reduced, the iron pipe 2 is excessively pressed by the screw 4 through the pad 4 and the like, so that the iron pipe 2 cannot be slid. The pressing force of the member 6 against the iron pipe 2 is kept substantially unchanged from that at normal temperature.
[0015]
On the other hand, when the temperature is high, the amount by which the outer diameter A of the iron pipe 2 increases is small compared to the amount by which the inner diameter of the aluminum housing 1 increases, but the pressing member 6 also extends in the pressing direction at the same time. For this reason, as in the prior art, as the inner diameter of the aluminum housing 1 is increased, the pressing of the screw against the iron pipe 2 via the pad 4 or the like is loosened and the play of the pressing member 6 does not increase. The pressing force on the iron pipe 2 is maintained in a state that is not substantially different from that at normal temperature.
Therefore, in either case of low temperature or high temperature, the pressing force of the pressing member 6 against the iron pipe 2 is maintained in an appropriate state that allows sliding without being influenced by the environmental temperature.
[0016]
Next, a second embodiment will be described with reference to FIG. This embodiment is substantially the same as the first embodiment, and the same members are denoted by the same numbers. The difference is that the axial direction of the screw hole 3a of the iron housing 3 is substantially parallel to the central axis direction of the iron pipe 2, that is, the longitudinal direction of the pressing member 6 is substantially parallel to the sliding direction of the iron pipe 2. Thus, the iron housing 3 of the first embodiment is rotated 90 degrees clockwise in the figure, and the side surface of the iron housing 3 is joined to the aluminum housing 1, and the cam 8 is a pressing force transmission member. It is the point which is comprised so that the pressing force of the pressing member 6 may be transmitted to the iron pipe 2 outer peripheral surface via.
[0017]
In the figure, the length of the pressing member 6 is set equal to or substantially equal to the outer diameter A of the iron pipe 2 (same as in the first embodiment). The iron housing 3 is fixed to the aluminum housing 1 by bolting or fitting with a fixing portion 1b indicated by oblique lines. The cam 8 has a shape that simultaneously contacts the left end of the pressing member 6 in the drawing and the contact plate 9 and rotates in the direction of arrow D in response to the pressing of the pressing member 6 to contact the communication hole 1a. The iron pipe 2 can be pressed through the plate 9. Therefore, the iron housing 3 is fixed at an appropriate position of the aluminum housing 1 so that the cam 8 can use the communication hole 1a, and the cam 8 is located near the fixed portion 1b of the iron housing 3 by the support portion 8a. 10 is rotatably supported by the shaft 10.
[0018]
In this configuration, the pressing force in the arrow E direction of the pressing member 6 by tightening the screw 7 is changed to the pressing force in the arrow F direction substantially orthogonal to the arrow E direction by the cam 8, and the contact plate 9 and the pad 4 are moved. To the outer peripheral surface of the iron pipe 2. Since the actions at low temperatures and high temperatures are the same as those in the first embodiment, description thereof will be omitted.
[0019]
Therefore, as in the first embodiment, when the iron housing 3 protrudes in a direction perpendicular to the sliding direction of the iron pipe 2, an extra space is taken, and the degree of freedom in installation is increased. However, when the iron housing 3 is in a shape parallel to the sliding direction of the iron pipe 2 as in the second embodiment, it is easy to install and space saving can be achieved. Although not shown, the iron housing 3 can be attached at a free angle with respect to the sliding direction of the iron pipe 2.
[0020]
A third embodiment will be described with reference to FIG. This embodiment is substantially the same as the second embodiment, and the same members are denoted by the same reference numerals. The difference is that the cross-sectional area of the iron housing 3 and the pressing member 6 in the direction orthogonal to the pressing direction (arrow E direction) is made smaller, that is, the iron housing 31 and the pressing member 6 The space 61 is further saved by forming the member 61 and tightening with the thinner screw 71. The screw 71 is fixed to the iron housing 31 by the lock nut 12.
In this configuration, the operations of the pressing member 61 and the cam 8 are the same as those of the second embodiment, and the actions at low temperatures and high temperatures are the same as those of the first embodiment, and thus description thereof is omitted. .
[0021]
Next, a fourth embodiment will be described with reference to FIG. This embodiment is substantially the same as the third embodiment, and the same members are denoted by the same numbers. The difference is that an iron housing 32 having a substantially L-shaped cross-sectional shape is cut out and a pressing member 61 is slidably held in the pressing direction. This is the point of further space saving. In this configuration, the operations of the pressing member 61 and the cam 8 are the same as those of the second embodiment, and the actions at low temperatures and high temperatures are the same as those of the first embodiment, and thus description thereof is omitted. .
[0022]
Furthermore, a fifth embodiment will be described with reference to FIG. This embodiment is substantially the same as the fourth embodiment, and the same members are denoted by the same reference numerals. The difference is that the length of the pressing member 61 in the pressing direction is K times the outer diameter A of the iron pipe 2 and is shortened to be the pressing member 62, thereby further saving space. is there.
However, as shown in the figure, the constant K is the distance of the cam 81 in the direction orthogonal to the pressing direction from the axial center of the cam shaft 10 to the contact point with the pressing member 62, and the cam shaft 10 When the distance in the pressing direction from the axis center to the contact point with the contact plate 9 is β, K = α / β. The cam 81 has the same function as the cam 8 but has a shape corresponding to the pressing member 62 that has been shortened.
In this configuration, the operations of the pressing member 6 and the cam 8 are the same as those in the second embodiment, and the actions at the low temperature and the high temperature are the same as those in the first embodiment, so the description thereof is omitted. .
[0023]
Next, a sixth embodiment will be described with reference to FIG. This embodiment is substantially the same as the first embodiment, and the same members are denoted by the same numbers. The difference is that the iron housing 3 as the second housing has a cap shape with one side opened, and a screw 3c that is screwed into a screw 1c hole formed in the aluminum housing 1 is formed on the outer peripheral surface of the iron housing 3. It is formed. The iron housing 3 in which the pressing member 6 is inserted is screwed into the screw hole 1 c of the aluminum housing 1, and the end surface of the pressing member 6 exposed from the opening of the iron housing 3 is an iron pipe through the disc spring 5 and the pad 4. 2 is pressed. Thereafter, the iron housing 3 is fixed to the aluminum housing 1 by a lock nut 11. In this configuration, the operation and action of the pressing member at the low temperature and at the high temperature are the same as those in the first embodiment, and thus description thereof is omitted.
In the sixth embodiment, the pressing member 6 may be fitted to the iron housing 3 or may be joined at one end. Further, as in the second embodiment, the iron housing 3 can be disposed substantially parallel to the iron pipe 2 or at a free angle.
[0024]
The rattle prevention structure of each of the above embodiments can be applied to, for example, an electric telescopic steering column. In this case, since the effect that the telescopic sliding force does not change with temperature can be expected, the design and operation of the apparatus can be further facilitated.
[0025]
【The invention's effect】
As described above, according to the present invention, the longitudinal cross section of the second metal is substantially rectangular, and the length thereof is equal to or substantially equal to the outer diameter of the long member made of the first metal. An equal pressing member, a communication hole provided in a housing made of the second metal so that one end portion in the longitudinal direction of the pressing member can indirectly press the long member, and the first metal The housing includes a screw hole for holding the pressing member so as to be slidable in the longitudinal direction and tightening the pressing member with a screw to press the other end of the pressing member. Since the pressing member is also reduced at a low temperature as the housing inner diameter is reduced, the long member is excessively pressed by the pressing member and the long member is not slid. Preventing it from becoming possible It can be. Further, at the time of high temperature, as the inner diameter of the housing increases, the long member also extends in the pressing direction at the same time. Therefore, it is possible to prevent looseness of the long member due to loose pressure on the long member.
Therefore, in any case, the pressing force of the pressing member against the long member is maintained in an appropriate state that allows sliding without being influenced by the environmental temperature.
[0026]
Further, the second housing is fixed to the housing such that the longitudinal direction of the pressing member is parallel to the sliding direction of the long member, and the pressing force in the longitudinal direction of the pressing member is substantially orthogonal to this. Since the pressing force transmitting member for transmitting to the long member is provided instead of the pressing force, the shape in which the second housing protrudes is eliminated, so that the degree of freedom of installation is increased, and the space can be saved.
Furthermore, if the anti-rare structure of the present invention is applied to, for example, an electric telescopic steering column, the telescopic sliding force does not change with temperature, so that design and operation can be performed more easily.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a backlash prevention structure showing a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of a rattle prevention structure showing a second embodiment.
FIG. 3 is a cross-sectional view of a rattle prevention structure showing a third embodiment.
FIG. 4 is a cross-sectional view of a backlash prevention structure showing a fourth embodiment.
FIG. 5 is a cross-sectional view of a rattle prevention structure showing a fifth embodiment.
FIG. 6 is a cross-sectional view of a rattle prevention structure showing a sixth embodiment.
FIG. 7 is a partially exploded cross-sectional view showing a conventional rattle prevention structure.
FIG. 8 is a cross-sectional view showing a conventional rattle prevention structure.
[Explanation of symbols]
1 Aluminum housing (housing)
1a Communication hole 1c Screw hole 2 Iron pipe (long member)
3 Iron housing (second housing)
3a Screw hole 3b Through hole 3c Screw 6 Pressing member 7 Screw

Claims (4)

A tubular or rod-like long member made of a first metal;
A housing made of a second metal having a coefficient of thermal expansion different from that of the first metal and having the elongate member fitted therein ;
A screw for fastening the elongate member to the housing so as to be slidable in the elongate axial direction;
A pressing member made of the second metal and having a substantially rectangular cross-sectional shape in the longitudinal direction, the length of which is equal to or substantially equal to the outer diameter of the long member;
A communication hole provided in the housing so that one end side in the longitudinal direction of the pressing member can press the long member;
It consists of the first metal, holds the pressing member slidably in its longitudinal direction, has a screw hole for tightening with the screw and pressing the other end side in the longitudinal direction of the pressing member, A second housing fixed to a predetermined position of the housing where the pressing member can use the communication hole;
A backlash prevention structure characterized by comprising:   The second housing is fixed to the housing such that the longitudinal direction of the pressing member is substantially parallel to the sliding direction of the long member, and the pressing force in the longitudinal direction of the pressing member is applied to the second housing. The backlash prevention structure according to claim 1, further comprising a pressing force transmission member that transmits to the elongate member in place of a pressing force in a direction substantially orthogonal to the longitudinal member. Shaking prevention structure of claim 1, wherein said first metal is iron. The backlash prevention structure according to any one of claims 1 to 3, wherein the second metal is aluminum.

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