JPS6148608A - Contactedly moving guide shaft for bearing - Google Patents

Abstract

PURPOSE:To reduce the resistance value by providing a spiral groove on a guide shaft which guides a frame body so as to enable a linear reciprocating motion freely. CONSTITUTION:A round shaft 4' by which the linear guide of a frame body 1 is carried out is inserted into bearings 3 provided in the bearing parts 2 of the frame body 1. And, a spiral groove 5 is continuously formed on the external surface of the round shaft 4' along the overall length or nearly overall length. Thus, since the contacting surface between the round shaft 4' and the internal surface of the bearing 3 is lessened, the contact resistance is reduced.

Description

[Detailed Description of the Invention] This invention was invented to improve the performance of sliding guide bearing systems for linear sliding mechanisms in general machinery and to reduce manufacturing costs. In order to reduce the contact resistance with the guide shaft, the contact area is made small, and it has operating characteristics that are superior to those of commonly used round shafts.

Conventional contact guide shafts for bearings have been processed using a polishing process to ensure smoothness and prevent bending, as lathe finish cannot withstand use, or the best condition is a superfinishing process. Tsushiyu is usually applied as an additional work.

Therefore, although this results in a very high cost, as the performance of recent equipment has improved, smoothness and minimal bending are required, making it even more expensive. It has become.

Based on this current situation, this invention has a low resistance value.

The purpose is to manufacture a contact guide shaft that is easy to process.

First, a detailed explanation of the invention will be given using figures.

Figures 1 and 2 are simplified plan views of the transport mechanism. The base frame body (1) of a general transport mechanism has a bearing part (2) that is protruded from the body or is integral with the frame body (1), and a bearing (3) is inserted into the bearing part (2). .

The bearing (3) is designed to save sliding material and to be easy to process.
In addition, in order to stabilize the drive running of the frame body (1), many frames are divided into two parts as shown in Figure 1, but the comparatively small clonic frame (1') is of the two-part type described above. There is also one shown in Figure 2 in which the bearing (3) is shaped like a single pipe without using a bearing.

The form of these basic sliding motions is the drive source mounted on the frame body (1), i.e., the pinion gear of the motor fixed to the frame body (1) + 1'). One example of this is to construct a drive mechanism or the like by screwing the meshed racks to predetermined stationary fixed locations within the device.

Most linear guides for the frame body (1) mentioned above use an alloy round shaft (4) with a predetermined length as shown in Figure 5, and the round shaft (4) is fitted with the aforementioned bearing. Hole (3) and bearing hole,
゛(3) Use a screw to pass through the fixed part inside the device and fasten it. The outer periphery of the cross section of the shaft (4) is circular with no unevenness, and the surface is smooth all the way around, and the same is true over the entire length. Strict precision is also required for bending and twisting.

The reason for this is that if the frictional resistance increases when the frame body (1) slides, the resistance will be too large depending on the location and will partially impede smooth movement.

A specific proposal for a contact guide shaft that has a low resistance value and is easy to process will be explained.

The shaft (4) in Fig. 6 is the shaft (4') for the contact guide of the invention.
The figure is a part of it. The shaft (4') is characterized by continuous spiral grooves (5) on the outer periphery of the entire length or approximately the entire length.

At first glance, you can imagine a threaded rod, but one with a very small thread pitch is unsuitable for the shaft (4') of the invention; on the other hand, the larger the thread pitch is, the more effective it is as a shaft (4'), It will become significantly better and better than the shaft (4').

The reason for this is that the requirement for two functions, straightness and smoothness, is in an immediate and inseparable relationship with the processing method.If the shaft, etc. is not bent and the surface is finished smooth, the heat generated during grinding is Must be released or removed as soon as possible. In other words, it is a well-known phenomenon that machining stress remains locally on the surface, causing bending and warping, and that grindability is also poor, making it difficult to obtain smoothness. Have difficulty.

Therefore, if only the outer diameter part of a threaded rod, etc., which has a large surface area, is processed, the processing heat can be quickly conducted away to the trough of the screw, which is not processed, and the grinding wheel will not touch this area. The grinding fluid is sufficiently poured into the area, which further improves the effect.

Generally, to shorten machining time and obtain high accuracy.

A centerless grinding method is used, or the above-mentioned threaded shaft, which requires outer diameter finishing, is the most suitable workpiece for this processing method. With the simple shape of the round shaft (4), since the workpiece is in contact with the entire surface of the grinding wheel, heat dissipation is poor, the smoothness is lost due to bending, and it is obvious that the machining time increases due to the large total surface area. If there is a large amount of heat, it will lead to more heat generation, and good results cannot be expected.

Therefore, a smooth shaft (4') with little bending is required for the aforementioned workpiece with a small thread pitch, but on the other hand, when using a sliding shaft (4'), a different perspective must be taken.

That is, the shaft (4') is inserted through the shaft (4') through the bearing hole (31(3)).
’) When moving the top, there will always be some error in the straightness of both shaft axes, so insert the shaft hole (3) at the edge of the intersection of the outer diameter surface of the shaft (4’) and the threaded slope. (3)-3- The edge part of the side surface is affected by the amount depending on the relationship with the fitting clearance, so especially when the thread pitch is extremely small, the above-mentioned thread edge is also related to the length of the bearing. However, there may be cases where the ball gets stuck over more than half the circumference, making it difficult to obtain a smooth slide.

Due to the above-mentioned reasons, the thread pitch is increased and double-thread threads are used to improve workability and functionality of the sliding shaft (4').
is required.

The screw groove (5) of the shaft (4') of the present invention does not use a general screw groove. That is, the shape of the thread groove is free to use any shape. Of course, it may be a semi-circular diameter like a commonly seen ball screw, or a trapezoidal triangular or square shape like a common screw.

Furthermore, since it is not intended to be used for thrust transmission, it is possible to use a spiral shape with very shallow grooves, and in this case, a large amount of cutting time can be saved.

As is known, when using a slightly deep groove (5), the processing time can be effectively shortened by using the rolling method. Because of the problem with the life of the rolling die, it is better to make it as shallow as possible considering that it is not used for thrust transmission as mentioned above.

When using a copper-based aluminum-based material that is easily plastically worked among metal materials, the screw groove (5) that does not require polishing is a rolled shaft that requires both outer diameter and smoothness. (4') can be considered, but in this case, the surface is coated with an abrasion-resistant material by plating or the like after molding.

Generally, a coating of gold, rhodium, nickel chrome, etc., or a silicon-based, carbon-based compound, etc. is used. If it is acceptable for other applications as long as it has moderate wear resistance, the screw (5) should not be designed with a deep valley because the plastic flow of the structure that occurs in the case of stainless steel type gives a large processing stress. is desirable.

The smaller the difference between the peak diameter and the valley diameter, the better.
On the contrary, it would be more convenient if it were shallow, since there would be no distortion due to aging.

The reason is the same as for the other alloys mentioned above.

The manufacturing methods and main points of various contact guide shafts (4') have been described above, and first, the functional benefits of using the contact guide shafts will be explained.

As mentioned previously, the contact area between the shaft (4') and the inner surface of the bearing hole (3) is reduced, so if a light-load linear guide bearing system is used, the contact resistance can be reduced, resulting in a small drive. A light (smooth) sliding motion can be made just by applying force.

It is clear that the general round shaft (4) is disadvantageous in this respect.

Another advantage that cannot be overlooked is the round shaft (4) and the bearing hole (
In combination with 3), if you look closely at any surface, there will be a cylindrical error, so there will always be unevenness.

If these slide, they will come into contact with each other and prevent smooth movement.

Therefore, when the contact guide shaft (4') of the invention is employed, it is possible to eliminate at least one of the errors that impede smooth movement.

Another benefit is that when lubricating oil is used, the thrust force must be increased for the round shaft (4) due to the viscosity of the lubricating oil, but it can be reduced for the shaft (4').

We have invented a contact guide shaft for linear sliding motion that is inexpensive, can perform highly accurate and smooth motion, and is durable as well.

[Brief explanation of the drawing]

Figures 1 and 3 are shown to support the explanation of the invention. FIG. 2 is a simplified plan view of a frame body (1) that performs linear reciprocating motion used in a general mechanical device. Figures 2 and 4 are side views of Figures 1 and 3, respectively. Figure 5 shows the frame body (1) generally used.
FIG. 4 is a diagram illustrating a contact guide shaft (4) for linear guide. Although the cross section is not shown, it is circular. Figure 6 and Figure 7 show the contact guide shaft (4) of the second application example of the invention.
'), and this part is simply expressed.

Claims (1)

[Scope of Claims] 1. A contact guide that penetrates through a sliding bearing hole provided in a frame body and is fixed to a predetermined stationary part of a device in which the frame body is installed, in order to guide the linear reciprocating motion, etc. of the frame body. Having a value outside the outer diameter and valley diameter values in the general screw standard used for thrust generation, transmission, or fastening in the shaft, and having a peak or valley shape that reduces the difference between the two diameters as appropriate, A spiral groove that is not related to the driving force of the frame body is provided on the outer periphery of the shaft over the entire length or a predetermined length to reduce the contact passage resistance between the frame body sliding bearing inner cylindrical surface and the shaft outer peripheral surface. The above-mentioned contact guide shaft was designed to be small. 2. An alloy material is used as the material of the contact guide shaft in claim (1). 3. An alloy material is used as the material of the contact guide shaft according to claim (1), and the surface thereof is coated with a single or multiple polymeric coating of other materials.