JP2022155769A - Measurement jig - Google Patents

Abstract

To provide a measurement jig capable of efficiently performing quality control of a multi-stage enlarged diameter hole when the multi-stage enlarged diameter hole is formed in a valve seat.SOLUTION: A measurement jig 1 measures a hole shape of a multi-stage enlarged diameter hole formed coaxially with a guide hole 11a at an open end 12a of a valve hole 12 formed coaxially with the guide hole 11a. The measurement jig 1 includes: a shaft portion 31 inserted into the guide hole 11a; a reference probe 32 integrally provided with the shaft portion 31 and positioned on a first stepped portion 21 that serves as a reference for measurement; a second movable probe 50 arranged movably in an axial direction of the shaft portion 31 with respect to an outer peripheral surface of the reference probe 32 and in contact with a second stepped portion 22; and a second measurement device 75 for measuring the amount of movement of the second movable probe 50 with respect to the reference probe 32. The second measurement device 75 measures the amount of movement of the second movable probe 50 with reference to a position where the reference probe 32 contacts the first stepped portion 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to a measuring jig for measuring the shape of a valve hole near its opening end.

In the development of automobiles with the theme of high output and low fuel consumption in recent years, it is important to realize a good combustion state in the combustion chamber of the engine in order to improve combustion efficiency. Therefore, it is important to maintain a certain level of precision in the production technology of the valve seats and valves that are incorporated into the cylinder head of the engine in order to manufacture engines with high output and low fuel consumption.

As a structure for inspecting the machining accuracy of the valve hole, there is the following structure. In Patent Document 1, in order to measure the height of a shroud portion formed around a part of the opening end of the valve hole, a positioning portion positioned at the opening end of the valve hole is provided with Accompanied by a moving measuring ring. The height of the shroud is measured by bringing the measuring ring into contact with the shroud. Further, in Patent Document 2, in order to measure the inner diameter of the shroud portion, a positioning portion that is positioned at the opening end of the valve hole is attached with a probe that turns around the positioning portion. The inner diameter of the shroud portion is measured by bringing the probe into contact with the inner wall of the shroud portion while turning the probe around the positioning portion.

JP 2014-062811 A JP 2014-055888 A

By the way, the processing accuracy of the face surface where the valve seat contacts the valve affects the sealing of the combustion chamber and the accuracy of the operation of the valve train mechanism, so processing accuracy even higher than that of the shroud is required. Become. Further, in recent years, there are cases where the face surface of the valve seat has a multi-stage enlarged diameter hole, which complicates the face surface of the valve seat, requiring even higher machining accuracy. When inspecting the machining accuracy of such a multi-stage enlarged diameter hole, the hole shape of the multi-stage enlarged diameter hole cannot be precisely measured by the above-described method.

For this reason, when measuring the hole shape of a multi-stage enlarged diameter hole, a contour shape measuring machine, which is a general-purpose precision measuring machine, has been used. However, in order to perform inspection with a contour measuring machine, it is necessary to transport the cylinder head out of the production line, or remove the valve seat from the valve hole, transport it to a clean room, etc., and transport it to the contour measuring machine. Efficient quality control was difficult due to the man-hours and time required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. The purpose is to provide jigs.

In order to achieve this object, the invention according to claim 1 provides a valve opening end (12a) of a hole (valve hole 12) formed coaxially with the reference shaft hole (guide hole 11a). A measuring jig (1) for measuring the hole shape of a multi-stage diameter-expansion hole which is formed in a plurality of stepped portions and whose diameter is expanded step by step, wherein the shaft portion (31 ), a reference probe (32) that is provided integrally with the shaft portion and positioned on a reference stepped portion (first stepped portion 21) that serves as a reference for measurement among the plurality of stepped portions, and the reference measurement A movable measuring element ( a second movable probe 50) and a movement amount detection section (second measuring device 75) that measures the amount of movement of the movable probe with respect to the reference probe; The moving amount of the movable probe is measured with reference to the position where the probe contacts the reference stepped portion.

Thus, when measuring the hole shape of the multi-step enlarged diameter hole, the movable probe is positioned with the reference probe positioned on the reference stepped portion, and the position at which the reference probe contacts the reference stepped portion is used as a reference. to measure the amount of movement of If the distance in the axial direction of the shaft portion between the reference stepped portion and the stepped portion different from the reference stepped portion can be grasped, the step different from the reference stepped portion can be detected by grasping the inner diameter of the reference stepped portion in advance. It is also possible to calculate the inner diameter of the portion and the surface width between the reference stepped portion and a stepped portion different from the reference stepped portion. Therefore, it is possible to grasp a plurality of lengths in the hole shape. In addition, these measurements can be performed by directly inserting the measuring jig into the multi-stage enlarged diameter hole, eliminating the need to use a separate contour measuring machine, enabling efficient quality control on the production line. . Therefore, it becomes possible to efficiently perform quality control of the multi-stage enlarged diameter hole.

The invention according to claim 2 is the measuring jig according to claim 1, wherein the measuring jig according to claim 1 is arranged movably in the axial direction of the shaft part with respect to the outer peripheral surface of the reference probe, and the plurality of stepped parts Among them, a reference movable probe (first movable probe 40) that contacts the reference step portion, and a reference movement amount detection section (first measuring device 71) that measures the amount of movement of the reference movable probe with respect to the reference probe. and wherein the reference movement amount detection section measures the movement amounts of the reference movable contact point and the movable contact point with reference to a position where the reference contact point contacts the reference stepped portion. characterized by

In this way, by using the reference movable probe in addition to the reference probe as the probe that contacts the reference stepped portion, the inner diameter of the reference stepped portion can be measured more precisely. Therefore, the inner diameter of the stepped portion different from the reference stepped portion and the surface width between the reference stepped portion and the stepped portion different from the reference stepped portion can be measured more precisely.

The invention according to claim 3 is the measuring jig according to claim 2, wherein the reference movable probe and the movable probe are formed in two grooves (first It is slidably disposed in the groove portion 36 and the second groove portion 37) and is held by an elastic member (O-ring 60) with respect to the reference probe. A holding groove (38, 48, 58) for holding the elastic member is formed on each of the outer peripheral surface and the outer peripheral surface of the movable probe.

Assuming that the reference probe, the reference movable probe, and the movable probe are held by the elastic member in this way, when the reference movable probe and the movable probe come into contact with the stepped portion, the elastic member is elastically deformed. Restoring force works. This restoring force serves as a measurement load, enabling precise measurement.

The invention according to claim 4 is the measuring jig according to any one of claims 1 to 3, wherein the multi-stage enlarged diameter hole is arranged in the valve hole (12) of the cylinder head (10) of the engine. A surface (second surface 26) formed on the valve seat (20) between the reference stepped portion and a stepped portion different from the reference stepped portion constitutes the face surface of the valve seat. and

In this way, the multi-stage enlarged diameter hole is formed in the valve seat arranged in the valve hole of the cylinder head of the engine, and the surface between the reference stepped portion and the stepped portion different from the reference stepped portion is the face surface of the valve seat. configure. As a result, the face width of the face of the valve seat can be measured precisely.

The invention according to claim 5 is the measuring jig according to any one of claims 1 to 4, wherein the plurality of stepped portions have an inclination angle with respect to the shaft portion that increases toward the opening end. Each of the reference probe, the reference movable probe and the movable probe has an inclined surface (33, 43, 53) that abuts on the stepped portion. The reference probe, the reference movable probe, and the inclined surfaces of the movable probe are each the inclined surface on the side closer to the opening end of the inclined surfaces adjacent to the stepped portion with which the probes abut. The inclination angle with respect to the shaft portion is formed so as to be smaller than the inclination angle and larger than the inclination angle of the inclined surface on the far side from the opening end.

In this way, the inclination angle of the inclined surface formed on each of the reference probe, the reference movable probe, and the movable probe is set to be smaller than the inclination angle of the inclined surface on the side closer to the opening end and on the side farther from the opening end. It is formed so as to be larger than the inclination angle of the inclined surface. As a result, since the inclined surfaces of the probes are in direct contact with the stepped portions, the hole shape of the multi-step enlarged diameter hole can be precisely measured.

It is a figure which shows the positional relationship with respect to the valve hole of the whole structure of a measuring jig, and a measuring jig. It is a figure which shows the whole structure of the measuring jig seen from the A direction of FIG. FIG. 4 is a diagram showing the configuration of a first movable probe and a second movable probe, where (A) is a configuration diagram of the first movable probe, and (B) is a configuration diagram of the second movable probe; FIG. 4 is a diagram showing a state in which a first movable probe and a second movable probe are held by a reference probe; FIG. 10A is a view showing the state of the O-ring when the valve seat comes into contact with the first movable stylus, FIG. 1A is a view showing the state before contact, and FIG. is. FIG. 3 is a cross-sectional view showing the detailed configuration of the valve seat; FIG. 4 is a diagram showing the inclination angle of the valve seat and the inclination angle of the probe, where (A) is a diagram showing the taper angle of the reference probe, and (B) is a diagram showing the inclination angle of the first movable probe; , and (C) are diagrams showing the tilt angle of the second movable stylus. FIG. 4 is a schematic diagram showing the state of the measuring jig during measurement;

Hereinafter, the measuring jig 1 of the first embodiment of the present invention will be described in detail with reference to the drawings. In the following description, in order to make the structures of the valve holes 12 and the valve seats 20 of the cylinder head 10 easier to understand, the drawings are described in which the openings face upward. In the following description, "up" or "down" means "up" or "down" in the drawings, except in special cases. Further, the axial direction means a direction parallel to the direction of the axis 11X of the guide hole 11a (the axial direction of the shaft portion 31).

The structure of the measuring jig 1 and its relationship with the vicinity of the valve hole 12 of the cylinder head 10 will be described with reference to FIG. FIG. 1 is a diagram showing the overall configuration of the measuring jig 1 and the positional relationship of the measuring jig 1 with respect to the valve hole 12. As shown in FIG. A measuring jig 1 measures the hole shape of a valve seat 20 arranged at an open end 12a of a valve hole 12 formed in a cylinder head 10 of an engine.

First, the structure of the cylinder head 10 will be explained. A valve hole 12 for intake or exhaust is formed in the cylinder head 10 . A guide hole 11a of the valve guide 11 is formed on the side opposite to the open end 12a of the valve hole 12 (lower side in the figure). The guide hole 11a is a hole into which a valve shaft (not shown) is inserted when the cylinder head 10 is in use. By moving the valve in the axial direction along the axis 11X of the guide hole 11a, intake and exhaust are performed from the cylinder head 10 to the combustion chamber (not shown). The valve hole 12 is formed coaxially with the axis 11X of the guide hole 11a. A valve seat 20 is arranged at the open end 12 a of the valve hole 12 . The valve seat 20 is formed with a multi-stage diameter-expansion hole whose diameter is enlarged stepwise while forming a plurality of stepped portions. The plurality of stepped portions are formed in a circular shape when viewed from the open end 12a side. A detailed description of the multi-stage enlarged diameter hole will be given later.

The configuration of the measuring jig 1 will be described with reference to FIGS. 1 and 2. FIG. FIG. 2 is a diagram showing the overall configuration of the measuring jig viewed from direction A in FIG. In the measuring jig 1, a first movable probe 40 and a second movable probe 50 are held by an O-ring 60 on the body portion 30, and the amount of movement of the first movable probe 40 and the second movable probe 50 is measured. A device 70 is configured to measure.

The body portion 30 has a shaft portion 31 inserted into the guide hole 11a, a reference probe 32 positioned with respect to the valve seat 20, and a measuring device holding portion 35 for fixing and holding the measuring device 70. are provided integrally.

The shaft portion 31 has a shaft diameter that fits into the guide hole 11 a of the valve guide 11 . As a result, the shaft portion 31 slides along the guide hole 11a, so that the body portion 30 can be axially moved along the axis 11X of the guide hole 11a.

The reference probe 32 has a substantially circular cross-section centered on the axis 11X (see FIG. 4) in a plane orthogonal to the axis 11X, and has a tubular shape as a whole. At the end (lower end) of the reference probe 32 on the shaft portion 31 side, a conical tapered surface 33 is formed, the diameter of which continuously increases with increasing distance from the shaft portion 31 . A first groove portion 36 and a second groove portion 37 are formed so as to extend in the axial direction on the outer peripheral surface (side surface in the drawing) of the reference probe 32 . A first movable probe 40 is arranged in the first groove portion 36 , and a second movable probe 50 is arranged in the second groove portion 37 . A holding groove 38 is formed along the circumferential direction on the outer peripheral surface of the reference probe 32 . An O-ring 60 is accommodated in the holding groove 38 in the circumferential direction. The retaining groove 38 thereby retains the O-ring 60 .

The measuring device holding part 35 has a cylindrical appearance and holds the measuring device 70 fixedly. Specifically, the bases 72 and 76 of the measuring device 70 are inserted through the through holes 35h that pass through the measuring device holding portion 35 in the vertical direction. Thereafter, a bolt or the like (not shown) is inserted into the holding hole 35b through the opening 35a (see FIG. 2) formed in the side surface of the measuring device holding portion 35, and the bases 72 and 76 are pressed and fixed at the tip of the bolt. Thereby, the measuring device holding section 35 holds the measuring device 70 fixedly.

Measuring device 70 is a standard dial gauge. The measuring device 70 of this embodiment has a first measuring device 71 and a second measuring device 75 . The first measuring device 71 has a base 72 , a measuring rod 73 having a tip portion 73 a and a display portion 74 . The measuring rod 73 is axially extendable with respect to the base 72 , and the tip 73 a of the measuring rod 73 is brought into contact with the first movable probe 40 . With this configuration, the movement amount measured by the movement of the measuring rod 73 is displayed on the display section 74 . The display unit 74 is provided with a needle 74a and a scale plate 74b (the scale is not shown) that rotates about the central axis in accordance with the movement of the measuring rod 73 in the axial direction. The numerical value of the scale indicated by the needle 74a is measured as the amount of movement of the first movable probe 40. As shown in FIG.

The second measuring device 75 has a base 76 , a measuring rod 77 having a tip portion 77 a and a display portion 78 . Since the structure of the second measuring device 75 is the same as that of the first measuring device 71, detailed description thereof will be omitted. Note that the configuration of the measuring device 70 is not limited to this, and may be other than a dial gauge as long as it can measure the amount of movement of the first movable probe 40 and the second movable probe 50 in the axial direction.

The configuration of the movable probe will be described with reference to FIG. 3A and 3B are diagrams showing configurations of the first movable probe 40 and the second movable probe 50. FIG. 3A is a configuration diagram of the first movable probe 40, and FIG. 4 is a configuration diagram of a two-movable stylus 50. FIG.

The first movable probe 40 has a flat surface 41 formed on the surface that abuts on the distal end portion 73a of the measuring rod 73 of the first measuring device 71, and an inclined surface 43 on the surface that abuts on the multi-stage enlarged diameter hole of the valve seat 20. It is formed. Further, a sliding surface 45 facing the first groove portion 36 of the reference probe 32 and slidable relative to the first groove portion 36 is formed so as to be parallel to the axial direction. A retaining groove 48 for retaining an O-ring 60 is formed in the outer radial surface of the child 32 .

The second movable probe 50 has a flat surface 51 formed on the surface that abuts on the tip portion 77a of the measuring rod 77 of the second measuring device 75, and an inclined surface 53 on the surface that abuts on the multi-stage enlarged diameter hole of the valve seat 20. It is formed. A sliding surface 55 facing the second groove portion 37 of the reference probe 32 and slidable relative to the second groove portion 37 is formed so as to be parallel to the axial direction. A retaining groove 58 for retaining the O-ring 60 is formed in the outer radial surface of the child 32 .

A configuration in which the movable probe is held by the reference probe will be described with reference to FIG. FIG. 4 is a diagram showing a state in which the first movable probe 40 and the second movable probe 50 are held by the reference probe 32. As shown in FIG. When viewed from the direction of FIG. 4 (upward in the axial direction), the first movable probe 40 is arranged so as to fit into the first groove portion 36 of the reference probe 32, and the holding groove of the first movable probe 40 A portion where 48 is formed protrudes from the outer periphery of the reference probe 32 . Similarly, the second movable probe 50 is arranged so as to fit into the second groove portion 37 of the reference probe 32 , and the portion of the second movable probe 50 in which the holding groove 58 is formed is the reference probe 32 . protrude from the outer circumference of In this state, the O-ring 60 accommodated and held in the holding groove 38 of the reference probe 32 spans over the holding groove 48 of the first movable probe 40 and the holding groove 58 of the second movable probe 50. be As a result, the first movable probe 40 and the second movable probe 50 are held by the reference probe 32 .

In this embodiment, the O-ring 60 is used as the holding member for the first movable probe 40 and the second movable probe 50, but the present invention is not limited to this. However, since the holding member is required to be elastically deformed, it is composed of at least some kind of elastic member.

FIG. 5 shows the state of the O-ring 60 during measurement. 5A and 5B show the state of the O-ring 60 when the valve seat 20 contacts the first movable contact 40. FIG. 5A shows the state before contact, and FIG. B) is a diagram showing a state at the time of contact.

As shown in FIG. 5A, before the valve seat 20 contacts the first movable probe 40, it is held in the holding groove 38 of the reference probe 32 and the holding groove 48 of the first movable probe 40. No load from the valve seat 20 is applied to the O-ring 60 . As shown in FIG. 5B, when the valve seat 20 contacts the first movable probe 40, the valve seat 20 pushes the first movable probe 40 up. As a result, the O-ring 60 is elastically deformed by being sandwiched between the holding groove 38 of the reference probe 32 and the holding groove 48 of the first movable probe 40 . The O-ring 60 generates a restoring force by being elastically deformed. This restoring force becomes the measurement load. The state of the O-ring 60 when the valve seat 20 abuts on the second movable probe 50 is also the same as when it abuts on the first movable probe 40, so the description is omitted.

With reference to FIG. 6, the hole shape of the multi-stage enlarged diameter hole formed in the valve seat 20 to be measured will be described in detail. FIG. 6 is a sectional view showing the detailed configuration of the valve seat 20. As shown in FIG. The multi-stage enlarged diameter hole formed in the valve seat 20 is composed of a plurality of continuous inclined surfaces whose inclination angle with respect to the axis 11X of the valve hole 12 gradually increases as it approaches the open end 12a from the side near the shaft portion 31 of the valve hole 12. A stepped portion is formed and a portion where the inclination angle changes.

The plurality of stepped portions formed on the valve seat 20 are a first stepped portion 21, a second stepped portion 22, and a first stepped portion 21, a second stepped portion 22, and a first stepped portion 21, a second stepped portion 22, and a first stepped portion 21, a second stepped portion 22, and a first stepped portion 22, from an opening end 20a of the valve seat 20 on the side of the opening end 12a of the valve hole 12. They have a third step 23 and are adjacent to each other in that order. All of the steps are circular when viewed from the axial direction. The inner diameter of the first stepped portion 21 is the inner diameter D1, and the inner diameter of the second stepped portion 22 is the inner diameter D2.

In addition, between the plurality of stepped portions of the valve seat 20, an inclined surface having a predetermined inclination angle with respect to the axis 11X of the guide hole 11a is formed. Specifically, from the open end 20a of the valve seat 20 on the side of the open end 12a of the valve hole 12, a first surface 25, a second surface 26, and a third surface 27 are formed downward in the drawing. Adjacent to. A first surface 25 is formed between the open end 20a and the first step 21, a second surface 26 is formed between the first step 21 and the second step 22, and a third surface 27 is formed between the first step 21 and the second step 22. is formed between the second step portion 22 and the third step portion 23 .

Here, the second surface 26 constitutes the face surface of the valve seat 20 . Since the face surface is the surface with which the valve abuts, it is preferable that the dimensions can be grasped in detail. Specifically, the face width W of the face surface is the width between the inner diameter of the first stepped portion 21 and the inner diameter of the second stepped portion 22 on the face surface.

Further, the multi-step enlarged diameter hole is a plurality of continuous inclined surfaces whose inclination angle with respect to the axis 11X of the guide hole 11a increases stepwise from the side near the shaft portion 31 of the valve hole 12 toward the open end 12a. Therefore, when the inclination angle of the first surface 25 is the inclination angle θ1, the inclination angle of the second surface 26 is the inclination angle θ2, and the inclination angle of the third surface 27 is the inclination angle θ3, the relationship θ1>θ2>θ3 is established. It holds.

Next, the relationship between the tilt angle of the valve seat and the tilt angle of the stylus will be shown. 7A and 7B are diagrams showing the relationship between the inclination angle of the valve seat and the inclination angle of the probe. FIG. 7A shows the taper angle (inclination angle) of the reference probe 32. FIG. 7B) is a diagram showing the inclination angle of the first movable probe 40, and FIG. 7C is a diagram showing the inclination angle of the second movable probe 50. FIG.

As shown in FIG. 7A, the tapered surface 33 of the reference probe 32 has a taper angle θ33 with respect to the axis 11X of the guide hole 11a. Specifically, the taper angle θ33 is the first angle on the side closer to the open end 12a of the inclined surfaces (the first surface 25 and the second surface 26) adjacent to the first stepped portion 21 with which the reference probe 32 abuts. It is formed so as to be smaller than the inclination angle θ1 of the surface 25 . Furthermore, the taper angle θ33 is formed to be larger than the inclination angle θ2 of the second surface 26 on the far side from the open end 12a. With this configuration, the tapered surface 33 of the reference probe 32 comes into contact with the first step portion 21 .

As shown in FIG. 7B, the inclined surface 43 of the first movable probe 40 has an inclination angle θ43 with respect to the axis 11X of the guide hole 11a. Specifically, the inclination angle θ43 is the angle of inclination of the inclined surfaces (the first surface 25 and the second surface 26) adjacent to the first stepped portion 21 with which the first movable probe 40 abuts, which is closer to the opening end 12a. It is formed so as to be smaller than the inclination angle θ1 of the first surface 25 . Furthermore, the inclination angle θ43 is formed to be larger than the inclination angle θ2 of the second surface 26 on the far side from the open end 12a. With this configuration, the inclined surface 43 of the first movable probe 40 comes into contact with the first stepped portion 21 .

As shown in FIG. 7C, the tapered surface 53 of the second movable probe 50 has an inclination angle θ53 with respect to the axis 11X of the guide hole 11a. Specifically, the inclination angle θ53 is the first angle on the side closer to the open end 12a of the inclined surfaces (the second surface 26 and the third surface 27) adjacent to the second stepped portion 22 with which the second movable probe 50 abuts. It is formed so as to be smaller than the inclination angle θ2 of the two surfaces 26 . Furthermore, the inclination angle θ53 is formed to be larger than the inclination angle θ3 of the third surface 27 on the far side from the open end 12a. With this configuration, the inclined surface 53 of the second movable probe 50 comes into contact with the second stepped portion 22 .

A measuring method using the measuring jig 1 configured as described above will be described with reference to FIG. FIG. 8 is a schematic diagram showing the state of the measuring jig 1 during measurement. Before starting the measurement, the shaft portion 31 of the main body portion 30 is inserted from the open end 12a of the valve hole 12 and inserted into the guide hole 11a of the valve guide 11 . This allows the body portion 30 to move axially along the axis 11X of the guide hole 11a.

When the main body portion 30 is moved in the axial direction, the conical tapered surface 33 of the reference probe 32 of the main body portion 30 hits the entire circumference of the first stepped portion 21 of the valve seat 20 . Thereby, the reference probe 32 is positioned with respect to the valve seat 20 .

With the reference probe 32 positioned on the first stepped portion 21 , the inclined surface 43 of the first movable probe 40 hits the first stepped portion 21 . Here, when the first movable probe 40 moves relative to the reference probe 32 , the amount of movement of the first movable probe 40 in the axial direction can be read from the display section 74 of the first measuring device 71 .

With the reference probe 32 positioned on the first stepped portion 21 , the inclined surface 53 of the second movable probe 50 hits the second stepped portion 22 . At this time, when the second movable probe 50 moves relative to the reference probe 32 , the amount of movement of the second movable probe 50 in the axial direction can be read from the display section 78 of the second measuring device 75 .

In this manner, the measurement jig 1 can acquire the amount of axial movement of each of the first movable probe 40 and the second movable probe 50 with respect to the reference probe 32 . Accordingly, by grasping the inner diameter D1 of the first stepped portion 21 in advance, the inner diameter D2 of the second stepped portion 22 and the surface width W between the first stepped portion 21 and the second stepped portion 22 are also calculated. can.

As described above, according to the present embodiment, when measuring the hole shape of the multi-step enlarged diameter hole with the measuring jig 1 , the reference probe 32 is positioned in the first step portion 21 . The amount of movement of the second movable tracing stylus 50 is measured with reference to the position where is in contact with the first stepped portion 21 . If the distance in the axial direction of the shaft portion 31 between the first step portion 21 and the second step portion 22 can be grasped, the second step portion 22 can be obtained by grasping the inner diameter of the first step portion 21 in advance. and the surface width W between the first stepped portion 21 and the second stepped portion 22 can also be calculated. Therefore, it is possible to grasp a plurality of lengths in the hole shape. In addition, these measurements can be performed by directly inserting a measuring jig into one multi-stage expanded diameter hole, and there is no need to use a separate contour measuring machine, so quality control can be performed efficiently on the production line. can. Therefore, it is possible to efficiently perform quality control of the multi-stage enlarged diameter hole formed in the valve hole 12 .

Further, according to the present embodiment, the first movable probe 40 is used in addition to the reference probe 32 as the probe that contacts the first stepped portion 21 . Since the reference probe 32 has a conical tapered surface 33 , it is positioned by coming into contact with the entire circumference of the first stepped portion 21 . On the other hand, the first movable probe 40 comes into contact with part of the first stepped portion 21 . In this way, by measuring the first stepped portion 21, which is a stepped portion that serves as a reference for measurement, with a plurality of probes that come into contact with each other in different manners, the inner diameter D1 of the first stepped portion 21 can be measured more precisely. can be done. In addition, with this configuration, even if there is a processing error, undulation, or the like on the inner peripheral surface of the hole when forming the hole shape of the multi-stage enlarged diameter hole, the measuring jig can be rotated by a predetermined angle to measure the inner peripheral surface of the hole. The inner diameter D2 of the second stepped portion 22 and the surface width W between the first stepped portion 21 and the second stepped portion 22 can be measured more precisely by detecting multiple points on the surface with the first movable probe. be able to.

Further, according to this embodiment, the reference probe 32 and the first movable probe 40 and the second movable probe 50 are held by the O-ring 60 . When the first movable probe 40 and the second movable probe 50 come into contact with the first stepped portion 21 and the second stepped portion 22, respectively, elastic deformation of the O-ring 60 acts as a restoring force. This restoring force serves as a measurement load, enabling precise measurement.

Further, according to this embodiment, the multi-stage enlarged diameter hole is formed in the valve seat 20 arranged in the valve hole 12 of the cylinder head 10 of the engine. A second surface 26 between the reference first step portion 21 and the second step portion 22 different from the first step portion 21 constitutes the face surface of the valve seat 20 . As a result, it is possible to provide the measuring jig 1 for precisely measuring the face width of the valve seat.

Further, according to this embodiment, the inclined surfaces 33, 43, and 53 are formed on the reference probe 32, the first movable probe 40, and the second movable probe 50, respectively. The inclination angles θ33, θ43, and θ53 of the inclined surfaces 33, 43, and 53 are smaller than the inclination angle of the inclined surface on the side closer to the opening end 12a among the two inclined surfaces adjacent to each step with which the probe contacts. Moreover, it is formed so as to be larger than the inclination angle of the inclined surface on the far side from the opening end. As a result, since the inclined surfaces of the probes are in direct contact with the stepped portions, the hole shape of the multi-step enlarged diameter hole can be precisely measured.

It should be noted that the present invention is not limited to the described embodiments and can be implemented in various ways. In the above-described embodiment, the measuring device 70 is a dial gauge, and only the amount of movement of the probe is displayed, but it is not limited to this. For example, the measuring jig 1 may be provided with a small computer having a processor and a storage unit, and the processor may automatically calculate the hole shape of the multi-stage diameter-enlarged hole from the amount of movement obtained by the measuring device 70. good too. In this case, the processor uses the data of the inner diameter D1 of the first stepped portion 21 set in advance in the storage unit and the data of the moving amount of the stylus acquired by the measuring instrument 70 to determine the distance of the second stepped portion 22. The inner diameter D2 and the surface width W of the face surface are calculated.

Reference Signs List 1... Measuring jig 10... Cylinder head 11a... Guide hole (reference shaft hole)
12...Valve hole (hole)
12a... Opening end 20... Valve seat 21... First step portion (reference step portion)
22 Second stepped portion (stepped portion different from the reference stepped portion)
26... Second surface 31... Shaft part 32... Reference probe 33... Tapered surface (inclined surface)
36... First groove portion (groove portion)
37... Second groove portion (groove portion)
38... Holding groove 38
40... First movable probe (reference movable probe)
43... Inclined surface 48... Holding groove 50... Second movable probe (movable probe)
53... Inclined surface 58... Holding groove 60... O-ring (elastic member)
71 First measuring device (reference movement amount detection unit)
75 ... Second measuring device (movement amount detection unit)

Claims (5)

A hole shape of a multi-stage enlarged diameter hole which is continuous with an open end of a hole formed coaxially with a reference shaft hole, is formed coaxially with the reference shaft hole, and has a plurality of stepped portions to form a plurality of stepped enlarged diameter holes. A measuring jig for measuring,
a shaft portion inserted into the reference shaft hole;
a reference stylus integrally provided with the shaft portion and positioned at a reference stepped portion serving as a reference for measurement among the plurality of stepped portions;
a movable probe disposed movably in the axial direction of the shaft portion with respect to the outer peripheral surface of the reference probe and abutting on a stepped portion different from the reference stepped portion among the plurality of stepped portions;
a movement amount detection unit that measures the amount of movement of the movable probe with respect to the reference probe;
A measuring jig, wherein the movement amount detection unit measures the amount of movement of the movable probe based on a position where the reference probe contacts the reference stepped portion. a reference movable probe disposed movably in the axial direction of the shaft portion with respect to the outer peripheral surface of the reference probe and abutting on the reference stepped portion among the plurality of stepped portions;
a reference movement amount detection unit that measures the amount of movement of the reference movable probe with respect to the reference probe,
2. The reference movement amount detection unit measures the movement amounts of the reference movable probe and the movable probe with reference to a position where the reference probe contacts the reference stepped portion. Measurement jig as described. The reference movable probe and the movable probe are slidably arranged in two grooves formed on the outer peripheral surface of the reference probe, and held by an elastic member with respect to the reference probe,
3. A holding groove for holding the elastic member is formed in each of the outer peripheral surface of the reference probe, the outer peripheral surface of the reference movable probe, and the outer peripheral surface of the movable probe. 2. The measuring jig according to 2. The multi-stage enlarged diameter hole is formed in a valve seat arranged in a valve hole of a cylinder head of the engine,
4. The measuring tool according to claim 1, wherein a surface between the reference stepped portion and a stepped portion different from the reference stepped portion constitutes a face surface of the valve seat. equipment. The plurality of stepped portions are formed of a plurality of continuous inclined surfaces whose inclination angles with respect to the shaft portion increase stepwise as they approach the open end,
each of the reference probe, the reference movable probe, and the movable probe has an inclined surface that contacts the stepped portion;
The inclined surfaces of the reference probe, the reference movable probe, and the movable probe each have an inclination angle of the inclined surface on the side closer to the opening end among the inclined surfaces adjacent to the step portion with which the probes abut. 5. The inclination angle with respect to the shaft portion is formed so as to be smaller than the inclination angle of the inclined surface on the far side from the opening end and larger than the inclination angle of the inclined surface on the far side from the opening end. The measuring jig described in .

Images