JPS628418Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a combination of bearings used in a carriage used in measuring instruments such as automatic recorders, automatic drafting machines, automatic printing machines, and the like.

The reciprocating table referred to in this proposal is installed across two shafts arranged in parallel, and the functional parts mounted thereon are placed according to the purpose of each use. A member that slides smoothly in the axial direction to ensure reliable operation.

Synthetic resin has come to be used for these carriages due to its corrosion resistance, light weight, reduction in driving torque and inertia due to weight reduction, and ease of manufacture.

In this invention, a synthetic resin carriage is installed across two parallel shafts, and a bearing part that makes sliding contact with each shaft is formed integrally with the carriage by insert molding. One of the bearing parts is a cylindrical multi-layered bush bearing in which a low-friction synthetic resin layer is adhered to the surface of the steel back metal, with a space between the bearing and the shaft in the axial direction of the shaft. The bearing is arranged with a small clearance with high precision between the bearings, and the bearing is provided with a rotation stopper with respect to the carriage at the abutting part, and the other part of the bearing is made of low-friction synthetic resin. A cylindrical or U-shaped bearing having a small clearance in a direction perpendicular to the plane containing the two shafts and a large clearance in a direction connecting the two shafts at right angles. The bearing is characterized in that it is fixed to the reciprocating carriage in the axial and circumferential directions through a protrusion or a dovetail groove provided on the outer circumferential surface of the bearing.

The two shafts are mainly provided one above the other, or are horizontally arranged and fixed in parallel within the above-mentioned equipment.

The reciprocating carriage that is fitted onto these shafts with bearings A and B and slides back and forth mainly supports its own weight and the load of the functional parts placed on it in the bearings A, and also supports the functions of the parts. The relative position of the component with respect to other members is also ensured here (of course, this depends on the interaction with the bearing part B, but this will be described later).

Therefore, the bearing used in the bearing part A needs to fit and slide into contact with the shaft with good precision and a small clearance, and must have excellent durability and ensure smooth sliding. The reason why one set of bearings, usually one set of two bearings, is used in the bearing portion A is to satisfy such requirements.

In other words, if there is only one bearing arranged in the bearing part A, when the carriage slides while a bending moment is applied in the direction along the plane containing the shaft, "attached-slip" often occurs. This is undesirable as it may result in "smooth sliding" and impede smooth sliding.

The above-mentioned multi-layer bush bearing, which is made of a combination of low-friction synthetic resin and steel backing metal, has good dimensional accuracy, has very little deformation due to aging or stress, and has excellent load carrying capacity and wear resistance. Therefore, it is most suitable as a bearing to be used in the bearing part A of the present invention.

For the bearing part B, one synthetic resin bearing is usually used.

The bearing used in this bearing part B is designed to accurately maintain the relative position of the carriage in the direction perpendicular to the plane containing the two shafts, and to operate the carriage by the operation of functional parts attached to the carriage. It is necessary to maintain the above-mentioned relative positions with high accuracy against the various stresses caused, and when the two shafts are arranged horizontally, the load of the carriage and functional parts is shared with the bearing part A. Its role is to provide support.

Therefore, in order to fulfill the above-mentioned role, the bearing used in bearing part B only needs to prevent the carriage from rotating around the axis of bearing part A, so stress and load should be considered. If you can withstand this, you only need to use one. However, if the allowable load is exceeded, one or more bearings may be used, as in bearing part A.

The bearings disposed in the bearing parts A and B are formed by so-called insert molding, or at least mounting holes into which the bearings are mounted are formed at the stage when the carriage made of synthetic resin is molded.

In either case, since the carriage is made of synthetic resin, there is a problem in accurately obtaining the dimension between the centers of the holes in the bearing parts A and B.

This is because the type of synthetic resin used for molding the carriage, the presence or absence of compounded components, and slight differences in molding conditions subtly affect dimensional accuracy.

In this invention, the inner hole of the bearing used in bearing part B is shaped to have a large clearance in the direction connecting the two shafts at right angles, primarily to address this problem. That's the reason.

Therefore, the inner hole of this bearing is usually formed into an ellipse having a long axis in a direction connecting the two shafts at right angles, or a U-shape with one side open in the direction.

Because of this configuration, when the two shafts are arranged vertically, the bearing of this bearing part B can substantially absorb the load of the carriage and the functional parts placed on the carriage. I don't accept it.

The bearing placed in the bearing part B has this role and also deals with the above-mentioned dimensional problem, so it must not fall off from the position where it is placed. Of course, if it loosens at that position and rotates even slightly,
The long axis of the bearing must not deviate from the direction that connects the book axes at right angles.

If such deviation occurs, smooth sliding of the carriage is significantly hindered.

Hereinafter, the bearing of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a perspective model diagram of a carriage shown to explain the combination of bearings, and FIG. 2 is a diagram of another embodiment.

Reference numerals 1 and 1' indicate carriages, and 2 and 2' indicate their base parts, respectively.

Reference numerals 3 and 3 indicate ears provided at one end of the base portion 2, and reference numeral 4 indicates an ear provided at the other end.

5, 5 are bearings attached to the ear parts 3, 3;
It constitutes the bearing part A of the carriage 1.

Reference numeral 6 denotes a bearing provided on the other ear portion 4, and constitutes a bearing portion B of the carriage 1.

Reference numerals 7 and 8 indicate shafts that are arranged parallel to each other in the lateral direction, and the shaft 7 is fitted into the bearings 5, 5, and the shaft 8 is fitted into the bearing 6.

The shaft 7 and the bearings 5, 5 are in sliding contact with each other with a small clearance with high precision.

The shaft 8 and the bearing part 6 have a large clearance 9 in the direction connecting the two shafts 7 and 8 at right angles, and there is substantially no sliding contact between them in this direction. However, in the direction perpendicular to the plane containing the two shafts 7 and 8, it is in sliding contact with a small clearance.

FIG. 3 is a longitudinal cross-sectional view showing an aspect of the bearing portion A in FIG. 1, in which the bearing 5 is cast and fixed to the ear portion 3 during molding of the carriage made of synthetic resin.

The bearing 5 is shown in a perspective view in FIG.
As shown in the enlarged cross-section of the thick part of the bearing, it is a multi-layer bush bearing made of a steel back metal 10 covered with a low-friction synthetic resin layer 12 via a porous sintered metal layer 11.

The bearing 5 has chamfered parts 13, 13 on both end faces, and the synthetic resin is molded to fill these parts, so that the bearing 5 does not move in the axial direction or fall off the ear part 3. Nothing happens.

The bearing 5 has a blank butt portion 14, as shown in FIG. This butt part 1
4 has a very small clearance when the bearing is in the free state.

In this type of bearing, when the bearing is fitted into the housing and the gap between the abutting portions becomes zero, the bearing inner hole becomes a perfect circle.

In the embodiment shown in FIG. 1, the bearing 5 is placed in a mold and molded at the same time when the carriage is molded, but the gate part of the injection mold is radially aligned with the abutting part 14. If molded so that they are located on the opposite side, the gap will be closed by the resin pressure during molding, and molten resin will not enter the inner hole through the gap.

Experiments have shown that the existence of the abutment part 14 of the bearing 5 has the effect of preventing the bearing from rotating when it is cast into the ear part of the carriage, even when there is no resin intrusion into the gap between this part. This has been confirmed by

FIG. 5, which shows the details of the material composition of the bearing 5 of the present invention, is equivalent to the bearings according to the technology disclosed in Japanese Patent Publication No. 31-2452, Japanese Patent Publication No. 49-44597, and Japanese Patent Application Laid-Open No. 54-45440. The steel backing 10 is a thin plate such as a cold rolled steel plate, the porous sintered alloy layer 11 is a copper-tin alloy,
The low friction synthetic resin layer 12 is made of tetrafluoroethylene resin, tetrafluoroethylene hexafluoropropylene copolymer, polyoxymethylene, or a blend thereof.

Examples of multi-layer bearings without such a porous sintered alloy layer 11 include Japanese Patent Publication No. 55-7146, all of which are similar to the bearing 5 of the present invention.
It is effectively used as

FIG. 6 is a longitudinal cross-sectional view showing how the reciprocating parts 5, 5 of the bearing part A are attached in the embodiment shown in FIG. A bearing mounting hole is provided in a portion near the periphery of the base portion 2' during molding of the carriage.

Also in this embodiment, the bearings 5, 5 are provided side by side at intervals in the axial direction. The use of a single long bearing is not adopted because it is difficult to achieve dimensional accuracy and increases sliding resistance.

15 is a pipe made of a light alloy such as aluminum, and 16 is a "necked part" provided approximately in the center of the pipe in the longitudinal direction. This “neck portion” 16 is
It is also possible to form the pipe in advance by pressing it with rollers, for example, before it is insert-molded into the carriage, but in the present invention, when the light alloy pipe 15 is set in the mold, a set of tapers are formed from both ends of the pipe. Insert molding was performed by inserting the core metal, and the "concave portion" 16 was formed using resin pressure during molding.

The light alloy pipe insert-molded in this way does not move or fall off in the axial direction, nor does it substantially rotate about its axis.

In this way, the multilayer bush bearings 5, 5 shown in FIG. 4 are press-fitted into the bearing mounting holes made of light alloy pipes provided in advance on the carriage.
Reference numeral 17 denotes a gap formed between the bearings 5, 5 and between the shaft 7' and the light alloy pipe 15.

In this configuration, since the bearings 5, 5 are tightly press-fitted into the light alloy pipe 15 at their back metal parts, there is no relaxation of press-fit stress during this time, and the bearings 5 do not wobble or fall off. .

In both of the embodiments shown in FIGS. 1 and 2, after the bearing 5 is mounted, the surface of the synthetic resin coating layer of the bearing is reamed, as necessary, to achieve even better dimensional accuracy. A bearing part A is obtained.

7 and 8 show embodiments of the low-friction synthetic resin bearing 6 used in the bearing part B, and FIG.
10 and 11 show another embodiment of the bearing 6'.

Reference numeral 18 denotes a protrusion provided on the outer circumferential surface of the bearing, which has a cross-sectional shape along the axial direction of the bearing 6 that is shorter than the length of the bearing and becomes wider as it moves away from the shaft center in the radial direction. are doing.

19 is a "dovetail groove" provided on the outer peripheral surface of the bearing,
It is provided along the axial direction of the bearing 6'. The protrusion 18 and the "dovetail groove" 19 can also be used together.

These bearings 6, 6 are set in a mold during molding of the carriage, and are fixed to the carriage by insert molding.

As shown in FIGS. 12 and 13, the synthetic resin constituting the carriage and the bearing 6 or 6' are engaged with each other at the protrusion 18 and/or "dovetail groove" 19, and are engaged with each other in the axial direction and around the axis. It is constructed so that it will not move or fall off.

Furthermore, these protrusions 18 or "dovetail grooves" 19 have a cross-sectional shape that becomes wider as they move away from the axial center or as they approach the axial center. Since the bearing 6 or 6' is engaged with the shaft, it has the effect of resisting dimensional changes (shrinkage) that would cause the bearing 6 or 6' to hug the shaft and maintain an appropriate bearing clearance.

The bearing 6 or 6' used in the bearing part B is
Preferred are polyoxymethylene resins, polyester resins, polyphenylene sulfide resins, tetrafluoroethylene resins, blends thereof, or mixtures thereof containing liquid lubricants or solid lubricants.

Since the present invention is a combination of the bearings explained above, the dimensional accuracy is good and the mounting manner is strong and reliable, so the slide and positioning of the carriage are smooth and accurate, and the carriage can be mounted on the carriage. It is possible to accurately and reliably operate the functional parts placed therein.

[Brief explanation of the drawing]

FIG. 1 is a perspective model diagram of a carriage, and FIG. 2 is a perspective model diagram of a carriage according to another embodiment, showing the mounting position and combination of the bearing of the present invention. Figure 3 shows bearing part A of the carriage shown in Figure 1.
FIG. 4 is a perspective view of the bearing used in the bearing part A of the present invention, and FIG. 5 is an enlarged sectional view of the thick part of the bearing. It is. FIG. 6 is a longitudinal cross-sectional view showing an example of how the bearing used in the bearing portion A of the carriage shown in FIG. 2 is mounted. Figures 7 and 8 are examples of cylindrical low-friction synthetic resin bearings of the present invention used in the bearing section B of the carriage, and Figure 7A shows an example in which both the inner and outer diameters are oval. 7B is an end view thereof, FIG. 7C is a side view thereof, FIG. 8A is an end view of a bearing having a circular outer diameter and an oval inner diameter, and FIG. 8B is a perspective view of a bearing having a circular outer diameter and an oval inner diameter. FIG. 9, 10, and 11 are embodiment views showing a U-shaped low-friction synthetic resin bearing of the present invention used in the bearing part B of a carriage; Figures 10A and 11A are
The respective end views, FIGS. 9B, 10B, and 11B are side views. 12th
13 are cross-sectional views of the bearing part B of the carriage,
12A and 13A are cross-sectional views in the direction perpendicular to the axis of each embodiment, and FIG.
12A and 13A respectively.
It is a sectional view taken along YY line in the figure. 1, 1'...Reciprocating carriage, 5, 5...Bearing used in bearing part A, 6, 6'...Low friction synthetic resin bearing used in bearing part B, 9...Large clearance, 13...Chamfering Part 15...Light alloy pipe,
16... Constriction, 18... Protrusion, 19... Dovetail groove.

Claims (1)

[Claims for Utility Model Registration] 1. A synthetic resin carriage 1 mounted across two shafts 7 and 8 arranged in parallel has bearing parts A and B in sliding contact with the respective shafts. It is formed integrally with the carriage 1 by insert molding, and the bearing part A is a cylindrical multi-layered bush bearing 5, in which a low-friction synthetic resin layer is adhered to the surface of the steel back metal. The bearings 5, 5 are arranged at intervals in the axial direction of the shafts and with a small clearance with high accuracy between them and the shaft 7, and the bearings 5, 5 are connected to the carriage 1 at the abutting portions 14. A rotation stopper is formed in the bearing part B, and the bearing part B has a cylindrical or U-shaped bearing 6, 6' made of a low-friction synthetic resin that extends in a direction perpendicular to the plane containing the two shafts 7, 8. has a small clearance, and is arranged with a large clearance 9 in the direction connecting the two shafts 7 and 8 at right angles, and the bearings 6,
6' is used by being incorporated into a carriage which is fixed to the carriage 1 in the axial direction and the circumferential direction at a protrusion 18 or a dovetail groove 19 provided on its outer circumferential surface. Bearing combination. 2. The bearing part A is formed integrally with the carriage 1 by insert molding and is press-fitted into a bearing mounting hole made of a light alloy pipe 15 having a constricted part 16 at the center in the longitudinal direction and both single parts of the mounting hole. A combination of bearings used by being incorporated into a carriage as claimed in claim 1, characterized in that the bearings are comprised of cylindrical multi-layered bush bearings 5, 5 which are attached to each other.