JPH07103704A - Measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a measuring apparatus which enables the holding of straightness accuracy of a mechanism guide part eliminating adverse effect due to thermal expansion already generated when different materials are used and achieves higher measuring accuracy with a higher freedom of designing free from any restriction by the material to be used. CONSTITUTION:A guide member which is provided on a column 4 of a measuring apparatus A is provided with a bracket 11 made of aluminum and a guide rail 12 made of iron with higher rigidity as guide to lift or lower an optical system unit 5 and a protruded part 11a formed jutting by a specified length at the lower end of the bracket 11 is joined securely at the lower end of the guide rail 12. On the other hand, a parallel plate spring unit 13 is mounted between the bracket 11 and the guide rail 12 holding elasticity in the direction of Z axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring machine and, for example, relates to a measuring machine for measuring the size and shape of an object to be measured while moving a measuring unit provided in the measuring machine with respect to the object to be measured. .

[0002]

2. Description of the Related Art As shown in FIG. 6, in a mechanism guide portion 20 of a measuring machine or the like which has conventionally been required to have high precision of parts, a high straightness is provided in a sliding portion of a slider 21 and a guide rail 22 which slide. Since it is required to have good properties, materials with high steel properties, mostly heavy materials such as iron, are used. Lightweight aluminum or the like is used for the bracket 23 that supports the guide rail 22, and an attempt has been made to reduce the weight of the entire measuring machine by joining them together.

[0003]

However, when different materials are combined and joined as described above, the so-called bimetal effect (when used in a factory, the difference in the coefficient of thermal expansion of each material is Since the temperature difference can reach 30 degrees, the influence is not negligible in a measuring machine that requires high accuracy.) A distorted portion is generated, and the guide rail 22 and the slider 2
It has been pointed out that there is a defect that the straightness accuracy of 1 is deteriorated and the practicality as a measuring machine cannot be endured. In order to prevent such a situation, the guide rail 22 and the bracket 2
Conventionally, a method of using a material having the same coefficient of thermal expansion for No. 3 or joining such that the adverse effect due to thermal expansion can be ignored has been taken, but in both cases, the degree of freedom in design is limited. Was occurring.

An object of the present invention is to solve the above problems and to eliminate the adverse effect of thermal expansion which has occurred when different materials are used in the past, and to maintain the straightness accuracy of the mechanism guide portion. The purpose of the present invention is to provide a measuring machine which has a high degree of freedom in design because the material to be used is not limited and the measurement accuracy is improved.

[0005]

Therefore, in the measuring machine of the present invention, in the measuring machine having the movable part, the member for guiding and supporting the movable part is formed by the first and second members having different thermal expansion coefficients. The first and second members are connected at one end side to each other and at the other end side via an elastic member.

[0006]

For example, the first and second members having different thermal expansion coefficients are used as members for guiding and supporting the movable part configured to support and move the measuring part for measuring the object to be measured. In the case of a measuring machine in which one end side that supports the second member is fixedly connected and the other end side is connected via an elastic member, it is a rule to use it in an environment where temperature and humidity are well controlled.
Due to the unavoidable temperature change of the environment, different expansion amounts or contraction amounts may occur in the first and second members having different thermal expansion coefficients. Even when different expansion and contraction occur in the first and second members in this way, expansion and contraction are caused by the elastic member interposed and connected at one end side,
Shrinkage is absorbed. Therefore, it is possible to eliminate the adverse effect of thermal expansion that occurs when different materials are used.

[0007]

Embodiments of the present invention using a measuring machine will be described in detail below with reference to the accompanying drawings. FIG. 1 shows the entire side surface of the measuring machine of this embodiment. This measuring machine A is provided with a Y-axis table 2 movably provided in a Y-axis direction on a base 1, and a Y-axis table 2 movably provided in an X-axis direction on the Y-axis table 2 and an object to be measured W placed on an upper surface thereof. An X-axis table 3 to be placed, a column 4 standing upright at a rear position on the base 1, and a Z-axis drive system B attached to the column 4.
The Z-axis slider 6 is provided so as to be vertically movable in the Z-axis direction, and the optical system unit 5 attached to the Z-axis slider 6. Therefore, the X-axis table 3 on which the object to be measured W is placed and the optical system unit 5 are provided so as to be relatively movable in the X-axis direction, the Y-axis direction, and the Z-axis direction. The optical system unit 5 that performs measurement on the object to be measured W includes a light emitting section 5a that emits illumination light L toward the object to be measured W and a CCD that receives reflected light L from the object to be measured W.
The sensor 5b and the data obtained by the CCD sensor 5b are arithmetically processed to measure the object W to be measured.

FIG. 2 shows a side surface of the Z-axis drive system. The Z-axis drive system B includes a bracket 11 (first member) that is attached to the column 4 and is made of aluminum for weight reduction, and a guide rail 12 (upper end and lower end supported by the bracket 11). Second member). The guide rail 12 is required to have high accuracy in order to guide the up-and-down movement of the optical system unit 5, and is made of iron having high steel property. And
A protrusion 11 a having a predetermined length is formed on the lower end of the bracket 11 and fixedly joined to the lower end of the guide rail 12. On the other hand, at the upper end of the bracket 11, the parallel leaf spring unit 13 (elastic member) is fixedly interposed so as to be bridged with the upper end of the guide rail 12.
That is, the lower end of the guide rail 12 is firmly fixed to the bracket 11, and the upper end thereof is fixed while maintaining elasticity in the Z-axis direction. Further, the bracket 11 is provided with a member B3 (nut) which is moved up and down with respect to the feed screw B2 by driving the motor B1. And the connecting member 14a is attached to this member B3 (nut),
Further, a slider 6 which slides on the guide rail 12 is arranged at the front end of the connecting member 14a. The optical system unit 5 is attached to the tip of the slider 6 and is used to measure the object W to be measured.

FIG. 3 shows a detailed structure of the parallel leaf spring unit 13 (elastic member). The parallel leaf spring unit 13 includes a spring steel material 13a having a predetermined elasticity and a reinforcing member 13b sandwiched from above and below the spring steel material 13a at a predetermined interval. Further, the reinforcing member 13b has a function as a fixing reinforcing material (washer) when the parallel leaf spring unit 13 is connected to the bracket 11 and the guide rail 12 by interposition. still,
When fixing to the bracket 11 and the guide rail 12, the lower reinforcing member 13b may be removed and attached as shown in FIG. Next, the operation of this embodiment will be described with reference to FIG. Although each member expands to some extent depending on the temperature change of the environment where the measuring machine A is placed, the guide rail 12 that requires particularly high accuracy allows a slight distortion due to expansion. is not.

As a countermeasure against such distortion (elongation, contraction) of the guide rail 12 due to thermal expansion, the fixing means to the bracket 11 has a feature. That is, by firmly fixing the lower end of the guide rail 12, the strain (elongation, contraction) due to thermal expansion is concentrated at the upper end, and this strain is absorbed by the parallel leaf spring unit 13 arranged at the upper end. Also, in absorbing the strain of this thermal expansion, expansion in the X-axis or Y-axis direction is completely blocked by the steel property of the parallel leaf spring unit 13, and expansion in the Z-axis direction is effectively absorbed. is there. Therefore,
According to the present embodiment, it is possible to achieve effective measures against thermal expansion in the guide rail 12 portion that adversely affects the measurement, and it is possible to use a material for weight reduction in a proper place, which impairs the degree of freedom in design. There is no. Further, by using the leaf spring to absorb the strain (elongation, contraction) due to the thermal expansion, the structure is simple and the cost is reduced.

The present invention has been described above with reference to the preferred embodiment, but the present invention is not limited to this embodiment, and various improvements and design changes can be made without departing from the gist of the present invention. For example, in the above embodiment, the parallel leaf spring unit 13 is used as the elastic body to be stretched between the bracket 11 and the guide rail 12, but the elastic body shown in the side view of FIG. 5 is not limited to this. The elastic body 23 integrally formed by using the spring steel material may be used. Further, although the Z-axis slider 6 has been described in the above embodiment, it may be used for other mechanism guide portions (X-axis, Y-axis, etc.).

[0012]

As described above, according to the measuring machine of the present invention,
Since it is possible to eliminate the adverse effect of thermal expansion due to the temperature change of the environment in which it is placed, it is possible to maintain high-precision measurement, while hindering the degree of freedom in design, such as being able to use materials for weight reduction in place. No, it leads to cost reduction.

[Brief description of drawings]

FIG. 1 is an overall side view of a measuring machine showing an embodiment of the present invention.

FIG. 2 is a side view of a Z-axis drive system of the measuring machine according to the above embodiment.

FIG. 3 is a detailed perspective view of a parallel leaf spring unit (elastic member) used in the measuring machine of the above embodiment.

FIG. 4 is an explanatory view showing an operation of a parallel leaf spring unit (elastic member) used in the measuring machine of the same embodiment.

FIG. 5 is a side view showing an elastic member used in another embodiment of the present invention.

FIG. 6 is a side view showing a state in which a conventional measuring machine is distorted by thermal expansion.

[Explanation of symbols]

 A measuring machine 11 bracket (first member) 12 guide rail (second member) 13 parallel leaf spring unit (elastic member)

Claims (1)

[Claims] 1. A measuring machine having a movable part, wherein a member for guiding and supporting the movable part is formed of first and second members having different thermal expansion coefficients, and one end sides of the first and second members are connected to each other. In addition, the measuring machine is characterized in that the other end side is connected via an elastic member.