JP2023009447A - Coaxiality measurement device - Google Patents

Abstract

To realize a coaxiality measurement device capable of suppressing deterioration of accuracy in measuring coaxiality between a reference hole arranged in a measured member and a measured part.SOLUTION: A coaxiality measurement device (20) includes: a reference shaft (22) to be inserted into a reference hole of a measured member; a gauge head (24) to be rotated around a central axis of the reference shaft (22) while having contact with a measured part of the measured member; a measurement device (23) for measuring a displacement amount of the gauge head (24); and a jig (31) having a horizontal surface (32) on which the measured member is placed. The reference shaft (22) includes: a shaft part (22a) to be inserted into the reference hole; and a tapered part (22b) to have contact with the horizontal surface (32) of the jig (31). A tapered angle (θ1) of the tapered part (22b) is double or less of an angle formed between the central axis of the reference hole of the measured member in a state of placement on the horizontal surface (32) of the jig (31) and the horizontal surface (32) of the jig (31).SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a coaxiality measuring device, for example, a device for measuring coaxiality between a reference hole provided in a member to be measured and a portion to be measured which is a shaft portion or a hole provided in the member to be measured. be.

For example, in order to maintain the airtightness of the combustion chamber of the engine and the performance of the engine, a high degree of coaxiality is required between a valve seat and a valve stem guide provided in the cylinder head of the engine.

The coaxiality between the valve seat and the valve stem guide can be measured using, for example, the coaxiality measuring device disclosed in Japanese Patent Application Laid-Open No. 2002-200012. The coaxiality measuring device of Patent Document 1 includes a reference shaft inserted into a valve stem guide, a probe that rotates around the central axis of the reference shaft while contacting the valve seat, and a measuring device that measures the displacement of the probe. The stylus is rotated while positioning the stepped portion of the reference shaft in contact with the end face of the valve stem guide.

JP 2006-317395 A

The applicant has found the following problems. The coaxiality measuring device of Patent Literature 1 requires that the end face of the valve stem guide be precisely machined so as to be orthogonal to the central axis of the valve stem guide, but there is a risk that the dimensional accuracy will vary depending on the machining accuracy.

Therefore, it is conceivable to measure the degree of coaxiality between the valve seat and the valve stem guide by placing the cylinder head on a jig and bringing the reference shaft into contact with the jig. Abrasion of the tip of the reference shaft due to contact between the tip of the reference shaft and the jig causes deterioration of measurement accuracy.

The present disclosure has been made in view of such problems, and provides a coaxiality measuring apparatus capable of suppressing deterioration in measurement accuracy of coaxiality between a reference hole provided in a member to be measured and a portion to be measured. .

A coaxiality measuring device according to an aspect of the present disclosure is a device for measuring the coaxiality between a reference hole provided in a member to be measured and a portion to be measured formed of a shaft portion or a hole provided in the member to be measured. There is
a reference shaft inserted into the reference hole;
a probe that rotates about the central axis of the reference axis while being in contact with the part to be measured;
a measuring device for measuring the amount of displacement of the probe;
a jig having a horizontal surface on which the member to be measured is placed;
with
The reference shaft has a shaft portion inserted into the reference hole and a tapered portion that contacts the horizontal surface of the jig,
The taper angle of the tapered portion is not more than twice the angle formed between the horizontal plane of the jig and the central axis of the reference hole of the member to be measured when the member is placed on the horizontal plane of the jig.

Advantageous Effects of Invention According to the present disclosure, it is possible to realize a coaxiality measuring device capable of suppressing deterioration in measurement accuracy of coaxiality between a reference hole provided in a member to be measured and a portion to be measured.

FIG. 4 is a cross-sectional view showing a state in which a cylinder head whose coaxiality between a valve stem guide and a valve seat is to be measured by the coaxiality measuring device of the embodiment is placed on a horizontal plane of a jig; It is a figure which shows the coaxiality measuring machine of the coaxiality measuring apparatus of embodiment. FIG. 3 is an enlarged view of part III of FIG. 2;

Hereinafter, specific embodiments to which the present disclosure is applied will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

First, a configuration example of a cylinder head in which the coaxiality between the valve stem guide and the valve seat is measured by the coaxiality measuring device of the present embodiment will be described. FIG. 1 is a cross-sectional view showing a state in which a cylinder head whose coaxiality between a valve stem guide and a valve seat is to be measured by a coaxiality measuring device according to the present embodiment is placed on a horizontal plane of a jig.

The cylinder head 1 has an intake port 3 and an exhaust port 4 communicating with a combustion chamber 2, as shown in FIG. A valve seat 5 is provided on the combustion chamber 2 side of the intake port 3 . An end surface of the valve seat 5 on the side of the combustion chamber 2 is formed with, for example, a tapered face surface 5a.

A through hole 6 communicating with the intake port 3 is formed in the cylinder head 1 , and a valve stem guide 7 is inserted into the through hole 6 . The valve stem guide 7 has a guide hole 7a into which the stem of the intake valve is slidably inserted.

A valve seat 8 is provided on the combustion chamber 2 side of the exhaust port 4 . An end surface of the valve seat 8 on the side of the combustion chamber 2 is formed with, for example, a tapered face surface 8a.

A through hole 9 communicating with the exhaust port 4 is formed in the cylinder head 1 , and a valve stem guide 10 is inserted into the through hole 9 . The valve stem guide 10 has a guide hole 10a into which the stem of the exhaust valve is slidably inserted.

In order to measure the coaxiality between the valve seat 5 and the valve stem guide 7 of the cylinder head 1 or the coaxiality between the valve seat 8 and the valve stem guide 10, the coaxiality measuring device 20 of the present embodiment is used. Used.

Next, the configuration of the coaxiality measuring device 20 of this embodiment will be described. FIG. 2 is a diagram showing a coaxiality measuring device of the coaxiality measuring device of the present embodiment. FIG. 3 is an enlarged view of part III of FIG. A coaxiality measuring device 20 of the present embodiment includes, for example, a coaxiality measuring machine 21 and a jig 31 as shown in FIGS.

The coaxiality measuring machine 21 includes a reference shaft 22, a measuring device 23 and a probe 24, as shown in FIG. The reference shaft 22 is inserted into the guide hole 7 a of the valve stem guide 7 of the cylinder head 1 or the guide hole 10 a of the valve stem guide 10 .

The reference shaft 22 has a substantially cylindrical shape as a basic shape, and as shown in FIG. 2, has a shaft portion 22a and a tapered portion 22b. The shaft portion 22 a is inserted into the guide hole 7 a of the valve stem guide 7 of the cylinder head 1 or the guide hole 10 a of the valve stem guide 10 . The axial length of the shaft portion 22 a is longer than the axial length of the valve stem guide 7 or the valve stem guide 10 .

Then, for example, as will be described later, the shaft portion 22a is inserted into the guide hole 7a of the valve stem guide 7 of the cylinder head 1 placed on the horizontal surface 32 of the jig 31 or the guide hole 10a of the valve stem guide 10. With the tapered portion 22b of the reference shaft 22 in contact with the horizontal surface 32 of the jig 31, all or part of the region 22c surrounded by the guide hole 7a of the valve stem guide 7 or the guide hole 10a of the valve stem guide 10 in the shaft portion 22a. The diameter of the portion is substantially equal to the diameter of the guide hole 7a of the valve stem guide 7 or the guide hole 10a of the valve stem guide 10. As shown in FIG.

As a result, with the region 22c of the shaft portion 22a inserted into the guide hole 7a of the valve stem guide 7 or the guide hole 10a of the valve stem guide 10, at least a portion of the region 22c of the shaft portion 22a is inserted into the guide hole of the valve stem guide 7. It can be brought into substantially surface contact with the hole 7a or the guide hole 10a of the valve stem guide 10, and the reference shaft 22 can be stabilized.

The tapered portion 22b has a substantially conical shape as shown in FIG. The taper angle .theta.1 of the taper portion 22b is determined, for example, by the center axis L1 of the guide hole 7a of the valve stem guide 7 and the jig when the cylinder head 1 is placed on the horizontal surface 32 of the jig 31 as described later. 31 and the horizontal plane 32 of the jig 31, or twice the angle .theta.3 formed between the central axis L2 of the guide hole 10a of the valve stem guide 10 and the horizontal plane 32 of the jig 31.

That is, the inclination angle θ4 formed between the central axis L3 of the reference shaft 22 and the tapered surface is the angle θ2 formed between the central axis L1 of the guide hole 7a of the valve stem guide 7 and the horizontal plane 32 of the jig 31, or the valve stem The angle θ3 formed between the center axis L2 of the guide hole 10a of the guide 10 and the horizontal plane 32 of the jig 31 is substantially equal.

As a result, in a state in which the shaft portion 22a is inserted into the guide hole 7a of the valve stem guide 7 of the cylinder head 1 placed on the horizontal surface 32 of the jig 31 or the guide hole 10a of the valve stem guide 10, the tapered portion 22b and The horizontal surface 32 of the jig 31 can be brought into approximate line contact.

The measuring device 23 is, for example, a dial gauge, and measures the amount of displacement of the tracing stylus 24 . The measuring device 23 is fixed via a fixing jig 25 to a portion of the reference shaft 22 opposite to the tapered portion 22b. Therefore, the probe 24 can rotate around the central axis L3 of the reference shaft 22 as the reference shaft 22 rotates.

At this time, the fixing jig 25 is preferably slidable with respect to the reference shaft 22 . The fixing jig 25 has, for example, a base that is fixed to the reference shaft 22, and a measuring device 23 that is fixed to the tip of the fixing jig 25. It may be provided with interlocking arms. As a result, the probe 24 is positioned substantially perpendicular to the reference axis 22 in the axial direction of the reference axis 22 (that is, the extending direction of the central axis L3 of the reference axis 22) and the central axis L3 of the reference axis 22. can be moved in any direction.

Furthermore, it is preferable that the fixing jig 25 is detachable with respect to the reference shaft 22 . Accordingly, it is possible to use the reference shaft 22 having a different diameter of the shaft portion 22a and a different taper angle θ1 of the tapered portion 22b according to the type of the cylinder head 1, and the versatility of the coaxiality measuring device 20 can be improved. .

As shown in FIG. 1, the jig 31 has a horizontal surface 32 on which the surface of the cylinder head 1 opposite to the combustion chamber 2 side can be placed.

Next, the flow of measuring the coaxiality between the valve seat 5 of the cylinder head 1 and the guide hole 7a of the valve stem guide 7 using the coaxiality measuring device 20 of the present embodiment will be described as a representative. The flow of measuring the coaxiality between the valve seat 8 of the cylinder head 1 and the guide hole 10a of the valve stem guide 10 using the coaxiality measuring device 20 of the present embodiment is substantially the same.

First, the cylinder head 1 is placed on the horizontal surface 32 of the jig 31 and the combustion chamber 2 of the cylinder head 1 is arranged on the opposite side of the horizontal surface 32 . Next, while inserting the shaft portion 22a of the reference shaft 22 of the coaxiality measuring machine 21 into the guide hole 7a of the valve stem guide 7 of the cylinder head 1, the tapered portion 22b of the reference shaft 22 is brought into contact with the horizontal surface 32 of the jig 31. Let

At this time, the diameter of all or part of the region 22c surrounded by the guide hole 7a of the valve stem guide 7 in the shaft portion 22a of the coaxiality measuring machine 21 is substantially equal to the diameter of the guide hole 7a of the valve stem guide 7, At least part of the peripheral surface of the shaft portion 22a is in surface contact with the peripheral surface of the guide hole 7a of the valve stem guide 7, and the central axis L3 of the reference shaft 22 is substantially the central axis L1 of the guide hole 7a of the valve stem guide 7. arranged to overlap.

The taper angle .theta.1 of the tapered portion 22b of the coaxiality measuring machine 21 is substantially equal to twice the angle .theta.2 formed between the central axis L1 of the guide hole 7a of the valve stem guide 7 and the horizontal plane 32 of the jig 31. , the tapered portion 22b is in substantially linear contact with the horizontal surface 32 of the jig 31. As shown in FIG.

Next, while the probe 24 of the measuring device 23 in the coaxiality measuring machine 21 is brought into contact with the face surface 5a of the valve seat 5, the coaxiality measuring machine 21 is rotated. As a result, the probe 24 rotates along the face surface 5 a of the valve seat 5 around the central axis L 1 of the guide hole 7 a of the valve stem guide 7 .

At this time, when the valve seat 5 and the guide hole 7a of the valve stem guide 7 are out of coaxiality, and when the valve seat 5 and the guide hole 7a of the valve stem guide 7 are not out of coaxiality, The displacement of the stylus 24 increases. Thereby, the coaxiality between the valve seat 5 and the guide hole 7a of the valve stem guide 7 can be measured based on the measurement result of the measuring device 23. FIG.

Here, since the coaxiality measuring machine 21 can be rotated while the tapered portion 22b of the reference shaft 22 in the coaxiality measuring machine 21 is brought into approximately linear contact with the horizontal surface 32 of the jig 31, the coaxiality measuring machine 21 can be stabilized. You can rotate it while it's on. Moreover, since the tapered portion 22b of the reference shaft 22 in the coaxiality measuring machine 21 is in substantially linear contact with the horizontal surface 32 of the jig 31, wear of the tapered portion 22b can be suppressed. Therefore, it is possible to suppress deterioration in measurement accuracy of the coaxiality between the valve seat 5 and the guide hole 7 a of the valve stem guide 7 .

Thus, the coaxiality measuring device 20 of the present embodiment can rotate the coaxiality measuring device 21 in a stable state. Moreover, wear of the tapered portion 22b of the reference shaft 22 in the coaxiality measuring machine 21 can be suppressed.

Therefore, the accuracy of measurement of the coaxiality between the valve seat 5 of the cylinder head 1 and the guide hole 7a of the valve stem guide 7 or the coaxiality between the valve seat 8 of the cylinder head 1 and the guide hole 10a of the valve stem guide 10 is degraded. can be suppressed.

Also, using a jig 31 having a horizontal surface 32, the degree of coaxiality between the valve seat 5 of the cylinder head 1 and the guide hole 7a of the valve stem guide 7 or the guide hole of the valve seat 8 of the cylinder head 1 and the valve stem guide 10 is measured. The degree of coaxiality with 10a can be measured, and there is no need to prepare a jig according to, for example, the valve pinch angle of the cylinder head.

Therefore, it is possible to inexpensively measure the coaxiality between the valve seat 5 of the cylinder head 1 and the guide hole 7a of the valve stem guide 7, or the coaxiality between the valve seat 8 of the cylinder head 1 and the guide hole 10a of the valve stem guide 10. can be done.

The present disclosure is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit of the present disclosure.

For example, the coaxiality measuring machine 21 selects (that is, exchanges) the reference shaft 22 having a different diameter of the region 22c of the shaft portion 22a and a different taper angle θ1 of the taper portion 22b according to the shape of the cylinder head 1. should be As a result, for example, differences in the diameter of the guide hole of the valve stem guide of the cylinder head 1 and the valve sandwich angle of the cylinder head 1 can be absorbed.

For example, in the above embodiment, the taper angle θ1 of the tapered portion 22b of the coaxiality measuring machine 21 is the angle θ2 formed by the central axis L1 of the guide hole 7a of the valve stem guide 7 and the horizontal plane 32 of the jig 31. Alternatively, the angle .theta.3 formed by the central axis L2 of the guide hole 10a of the valve stem guide 10 and the horizontal plane 32 of the jig 31 is approximately equal to twice the angle .theta.3, but may be less than twice.

At this time, for example, compared to the case where the tip of the reference shaft 22 has a spherical shape, it is easier to measure the wear amount of the tapered portion 22b, and the degree of coaxiality between the valve seat 5 of the cylinder head 1 and the guide hole 7a of the valve stem guide 7 is measured. Alternatively, it is possible to prevent deterioration of measurement accuracy of the coaxiality between the valve seat 8 of the cylinder head 1 and the guide hole 10a of the valve stem guide 10 in advance.

For example, the coaxiality measuring device 20 of the above embodiment measures the coaxiality between the valve seat (measured portion) 5 of the cylinder head (member to be measured) 1 and the guide hole (reference hole) 7a of the valve stem guide 7, or Although it is used to measure the coaxiality between the valve seat (measured portion) 8 of the cylinder head (measured member) 1 and the guide hole (reference hole) 10a of the valve stem guide 10, the present invention is not limited to this. For example, processing and adjustment of machines with opening and closing mechanisms such as check valves, dimensional control in the manufacture of valves with conical orifices for flow rate control or damping force generators, or chamfering provided at the mouth of cylindrical parts or holes It can be used to measure the position and coaxiality of parts.

Reference Signs List 1 cylinder head 2 combustion chamber 3 intake port 4 exhaust port 5 valve seat 5a face surface 6 through hole 7 valve stem guide 7a guide hole 8 valve seat 8a face surface 9 through hole 10 valve stem guide 10a guide hole 20 coaxial Degree measuring device 21 Coaxiality measuring machine 22 Reference shaft 22a Shaft portion 22b Tapered portion 22c Area 23 surrounded by guide holes of valve stem guide in shaft portion Measuring instrument 24 Measuring tip 25 Fixing jig 31 Jig 32 Horizontal planes L1, L2 Valve Central axis L3 of the guide hole of the stem guide Central axis of the reference axis θ1 Taper angles θ2 and θ3 of the tapered portion of the shaft portion Angle between the central axis of the guide hole of the valve stem guide and the horizontal plane of the jig θ4 Central axis of the reference axis and the taper angle

Claims (1)

A device for measuring coaxiality between a reference hole provided in a member to be measured and a portion to be measured comprising a shaft portion or a hole provided in the member to be measured,
a reference shaft inserted into the reference hole;
a probe that rotates about the central axis of the reference axis while being in contact with the part to be measured;
a measuring device for measuring the amount of displacement of the probe;
a jig having a horizontal surface on which the member to be measured is placed;
with
The reference shaft has a shaft portion inserted into the reference hole and a tapered portion that contacts the horizontal surface of the jig,
The taper angle of the tapered portion is less than or equal to twice the angle between the central axis of the reference hole of the member under test placed on the horizontal plane of the jig and the horizontal plane of the jig. measuring device.

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