Patent Application
20080089623
The present invention will be more clear from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention.
Referring to
Regarding the experiment of this embodiment, reference should be made to the following descriptions. The experiment shows that the optimum ambient temperature is 24° C., and humidity is optimally 55%. The acceptable ambient temperature and humidity (at which the elongation after absorbing oil is to be calculated) are 20-30° C., and 50-60%. The oil absorption in the test reaches saturation.
What follows are the oil used in the tests:
Various flexible materials are used in the oil-immersion test and are tested for their oil-proof properties, and the final products after oil-immersion test are installed in the guide device for testing the resistance value, and what follows are the test results:
1. results of the oil-immersion test:
To obtain an anticorrosive effect or for the purpose of lubrication, the surface of the guiding device is usually coated with oil or the whole guiding device is dipped into oil. The Synch-Motion spacer 10 made of thermoplastic Polyester-base elastomer or vulcanized thermoplastic rubber will not be stable when in contact with oil, and will affect the interval between spacer and the rolling elements. Therefore, the test results show the following problems:
1. Synch-Motion spacer 10 will expand when in contact with oil: the spacer 10 is formed with a plurality of receiving spaces 101 for reception of a plurality of rolling elements 11, the interval L is formed between the rolling elements 11 and the receiving spaces 101. If the Synch-Motion spacer 10 expands when in contact with oil, the receiving spaces 101 will be reduced, as a result, the Synch-Motion spacer 10 will hold the rolling elements 11 too tightly, or will interfere with the rolling elements 11. Accordingly, the resistance force of the rolling elements 11 will be too large. Further, the Synch-Motion spacer 10 will swell and fill up the return portion 12 when moving within the return portion 12, as a result, the guide device can't move smoothly (as shown in
2. Synch-Motion spacer 10 will contract when in contact with oil: the spacer 10 is formed with a plurality of receiving spaces 101 for reception of a plurality of rolling elements 11, the interval L is formed between the rolling elements 11 and the receiving spaces 101. If the Synch-Motion spacer 10 contracts when in contact with oil, the receiving spaces 101 will be enlarged, as a result, the Synch-Motion spacer 10 can't hold the rolling elements 11 tightly. Accordingly, the rolling elements 11 are likely to impact the returning portion 12, causing noise, or even worse, the rolling elements 11 are liable to fall off (as shown in
The abutting surface 104 is formed on each of the spacer elements 102 and is located on the outer periphery of the receiving space 101 and is arranged in the rolling direction of the rolling elements. The abutting portion 104 is made of thermoplastic polyamide elastomer with an elongation of 0-0.3%. The aforementioned oil-immersion tests show that the elongation of the thermoplastic polyamide elastomer can be controlled between 0% and 0.3%.
What follows are the test results of each of the thermoplastic polyurethane elastomer, the thermoplastic polyester-base elastomer, the vulcanized thermoplastic rubber immerged in soybean oil, hydrocarbon oil, and mineral oil.
1: immerged in soybean oil:
the elongation of the thermoplastic polyurethane elastomer and the vulcanized thermoplastic rubber after 100 hours oil immersion are over 1.75%. The elongation of the thermoplastic polyester-base elastomer is as great as 0.07% after 100 hours oil immersion, and will be 0.12% after 200 hours oil immersion (as shown
2. immerged in hydrocarbon oil:
the elongation of the thermoplastic polyurethane elastomer is 0.70% after 100 hours oil immersion and is over 1.02% after 200 hours oil immersion. The elongation of the vulcanized thermoplastic rubber is =0.93% after 100 hours oil immersion and is over −1.44% after 200 hours oil immersion. The elongation of the thermoplastic polyester-base elastomer is as great as 0.20% after 100 hours oil immersion, and will be 0.24 after 200 hours oil immersion (as shown
3. immerged in refined mineral oil:
the elongation of the thermoplastic polyurethane elastomer is 0.19% after 100 hours oil immersion and is over 0.47% after 200 hours oil immersion. The elongation of the vulcanized thermoplastic rubber is 6.23% after 100 hours oil immersion. The elongation of the thermoplastic polyester-base elastomer is 0.04% after 100, 200, 300, and 400 hours oil immersion (as shown
The test results show that the elongation of the thermoplastic polyurethane elastomer dipped is very high no matter it is dipped in immerged in soybean oil, hydrocarbon oil, or mineral oil, and the thermoplastic polyurethane elastomer will expand excessively. Sometimes, the vulcanized thermoplastic rubber will expand excessively, and sometimes will contract. These two materials are very unstable. Only the thermoplastic polyester-base elastomer is very stable no matter it is dipped in immerged in soybean oil, hydrocarbon oil, or mineral oil.
The final products (thermoplastic polyurethane elastomer, the thermoplastic polyester-base elastomer, the vulcanized thermoplastic rubber) after oil-immersion test are installed in the guide device for testing the increased resistance value, and what follows are the test results:
The increased resistance value of the thermoplastic polyurethane elastomer is 0.01-0.11 kg, the increased resistance value of the thermoplastic polyester-base elastomer is 0.002-0.009 kg, and the increased resistance value of the vulcanized thermoplastic rubber is 0.08-0.38 kg.
The increased resistance values of the respective materials after the elongation is stabilized are as follows: the increased resistance value of the thermoplastic polyurethane elastomer is 0.035-0.11 kg, the increased resistance value of the thermoplastic polyester-base elastomer is 0.002-0.008 kg, and the increased resistance value of the vulcanized thermoplastic rubber is 0.09-0.36 kg. If the increased resistance force is too great, the guide device can't move smoothly, causing false press. And if the expanded sized is too great, the interval between the receiving space 101 and the rolling elements 11 will be reduced to 0.025-0.035 mm, and will causing interference with the rolling elements, affecting the operation of the guide device.
If the contracted sized is too great, the receiving space 101 will be enlarged, as a result, the Synch-Motion spacer 10 can't hold the rolling elements 11 tightly. Accordingly, the rolling elements 11 are likely to impact the returning portion 12, causing noise, or even worse, the rolling elements 11 are liable to fall off.
The test results show that when the elongation is less than 0.3%, the resultant increased resistant force will not change dramatically and can be controlled within 0.01 kg, and thus the guide device can move smoothly. If the elongation is larger than 0.3%, the resultant increased resistant force will change dramatically and will have a great influence on the operation of the guide device. And the test results show that only the thermoplastic polyester-base elastomer is very stable, when its elongation reaches the saturation point, the increased resistance force is so small that it can be neglected, so that the guide device can move smoothly (as shown in
To summarize, the Synch-Motion spacer in accordance with the present invention comprises a plurality of spacer elements, and strip-shaped links. An abutting surface is formed on each of the spacer elements and is located on the outer periphery of the receiving space and is arranged in the rolling direction of the rolling elements. An interval L being 0.3% larger than the abutting portion is formed in the abutting portion and is located in the rolling direction of the rolling elements. The abutting portion is made of thermoplastic polyamide elastomer with an elongation of 0-0.3%. The elongation of the spacer after oil immersion is less than the interval between the rolling elements and the spacers, so that no interference will be caused between the rolling elements and the spacer when the guide device is coated with lubricant.
While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
