JP7574239B2 - Gas sensor clamping device - Google Patents

Description

The present invention relates to a gas sensor tightening device.

Patent Document 1 discloses a crimping device for a gas sensor. The crimping device crimps the gas sensor radially inward of the gas sensor. Specifically, the crimping device includes a pressing tool and multiple crimping tools. The pressing tool has a hole formed therein to accommodate the gas sensor and the multiple crimping tools. The inner wall surface of the pressing tool that forms the hole is tapered (conically) inclined with respect to the axis of the gas sensor.

This crimping device crimps the gas sensor by the following method. First, multiple crimping jigs are arranged around the axis of the gas sensor. Next, the pressing jig is moved relatively along the axial direction of the gas sensor, so that the gas sensor is inserted into the pressing jig and the inner wall surface of the pressing jig is abutted against the back surfaces of the multiple crimping jigs. Next, the pressing jig is moved further along the axial direction of the gas sensor, so that the multiple crimping jigs are pressed against the gas sensor. This causes the gas sensor to be crimped radially inward of the gas sensor.

Patent No. 5810120

As described above, the inner wall surface of the pressing jig is inclined in a tapered (conical) shape with respect to the axis of the gas sensor. Therefore, the radius of curvature of the inner wall surface of the pressing jig changes along the axial direction of the gas sensor. Specifically, the radius of curvature of the inner wall surface increases as it approaches the gas sensor and the crimping jig. Therefore, the radius of curvature of the inner wall surface of the pressing jig is the largest at the opening end (the entrance portion where the gas sensor is inserted) closest to the gas sensor and the crimping jig.

In contrast, the back surface of each of the multiple crimping jigs is the contact surface with the inner wall surface of the pressing jig, and is tapered to correspond to the inner wall surface of the pressing jig. The back surface of the crimping jig has a radius of curvature that is approximately the same as the radius of curvature of the opening end.

Therefore, when the gas sensor is crimped, the more the pressing tool moves toward the gas sensor, the smaller the contact area between the crimping tool and the inner wall surface of the pressing tool becomes. As a result, if the contact positions between each of the multiple crimping tools along the axial direction of the gas sensor and the pressing tool differ from one another, the crimping load will vary. In addition, even if the contact positions between each of the multiple crimping tools along the axial direction of the gas sensor and the pressing tool differ due to manufacturing variations in the multiple crimping tools, the crimping load will also vary.

The present invention aims to solve the above-mentioned problems.

An aspect of the present invention is a gas sensor crimping device that includes a plurality of crimping jigs arranged around the axis of a gas sensor extending along the axial direction for crimping the gas sensor, and a pressing jig that moves along the axial direction to press the plurality of crimping jigs against the gas sensor, in which a hole is formed in the pressing jig to accommodate the gas sensor and the plurality of crimping jigs, and the inner wall surface of the pressing jig that forms the hole has a plurality of first inclined planes that are inclined with respect to the axis of the gas sensor in order to press each of the plurality of crimping jigs against the gas sensor, and each of the plurality of crimping jigs has a second inclined plane that is in surface contact with a corresponding one of the plurality of first inclined planes.

In the present invention, the second inclined plane of each of the multiple crimping jigs is in surface contact with the corresponding first inclined plane. As a result, when the crimping jig slides along the first inclined plane, the first inclined plane and the second inclined plane are in smooth surface contact over the entire surface of the first inclined plane. As a result, the variation in the crimping load can be reduced.

FIG. 1 is a cross-sectional view of a crimping device. FIG. 2 is a plan view of the pressing jig and a plurality of crimping jigs. FIG. 3 is an enlarged plan view of the crimping jig. FIG. 4 is a rear view of the crimping jig. FIG. 5 is a cross-sectional view showing the operation of the crimping device. FIG. 6 is a cross-sectional view showing the operation of the crimping device. FIG. 7 is a cross-sectional view showing the operation of the crimping device. FIG. 8 is a cross-sectional view showing the operation of the crimping device.

Figure 1 is a cross-sectional view of a gas sensor clamping device 10 according to this embodiment. In the following description, the "gas sensor clamping device 10" will be referred to as the "clamping device 10."

The gas sensor 12 is, for example, a gas sensor that measures the gas concentration of a specific gas among the gases to be measured. The gas sensor 12 has a cylindrical body 14, a sensor element (not shown), a connector (not shown), a grommet 16, and a lead wire 18.

The cylindrical body 14 extends in a predetermined direction. In FIG. 1, the cylindrical body 14 extends in the vertical direction. The axial direction of the cylindrical body 14 is the axial direction of the gas sensor 12. A screw nut 20 is attached to the outer circumferential surface of the cylindrical body 14. The sensor element and the connector are disposed inside the cylindrical body 14. The connector is connected to the sensor element. The grommet 16 is an elastic body such as rubber. The grommet 16 is attached to the base end 22 of the cylindrical body 14. The lead wire 18 is connected to the connector. The lead wire 18 is inserted through a through hole (not shown) formed in the grommet 16 and is drawn out to the outside.

The base end 22 and grommet 16 of the cylindrical body 14 are crimped radially inward of the cylindrical body 14 by the crimping device 10. The crimped base end 22 and grommet 16 constitute the crimped portion 24. The crimped portion 24 is formed in an uneven shape in side view. The crimped portion 24 seals the inside of the cylindrical body 14. In the gas sensor 12, the location where the crimped portion 24 is formed becomes the base end of the gas sensor 12. In addition, in the gas sensor 12, the location opposite the base end (crimped portion 24) becomes the tip end of the gas sensor 12.

The crimping device 10 includes a drive source (not shown), a connecting plate 26, a base plate 28, multiple connecting rods 30, a first guide 32, a pressing tool 34, a second guide 36, multiple crimping tools 38, and multiple spring members 40. The crimping device 10 is arranged so that when the gas sensor 12 is crimped, the central axis 42 (axis, axial line) of the gas sensor 12 and the central axis 44 of the crimping device 10 are approximately coaxial.

The driving source is, for example, a cylinder. The rod of the cylinder extends approximately coaxially with the central axis 44 (central axis 42). The rod of the cylinder is connected to the connecting plate 26. The connecting plate 26 is a plate-shaped member that is perpendicular to the central axis 44. The connecting plate 26 is disposed approximately coaxially with the central axis 44.

The base plate 28 is disposed between the connecting plate 26 and the gas sensor 12. The base plate 28 is a plate-shaped member that is perpendicular to the central axis 44. The base plate 28 is disposed approximately coaxially with the central axis 44.

Each of the multiple connecting rods 30 is connected to a flat surface of the connecting plate 26 that faces the base plate 28. Each of the multiple connecting rods 30 is connected to an outer peripheral portion of the flat surface of the connecting plate 26. Each of the multiple connecting rods 30 extends from the connecting plate 26 along the central axis 44. The multiple connecting rods 30 pass through a plurality of through holes 46 formed in the base plate 28.

The first guide 32 is a cylindrical member. A through hole 48 large enough to insert the gas sensor 12 is formed inside the first guide 32. The first guide 32 is disposed on a plane of the base plate 28 that faces the gas sensor 12. The first guide 32 is disposed on the base plate 28 approximately coaxially with the central axis 44.

The pressing jig 34 is a tapered (conical) jig. A hole 50 large enough to accommodate the gas sensor 12 and multiple crimping jigs 38 is formed inside the pressing jig 34. The pressing jig 34 is positioned approximately coaxially with the central axis 44 by fitting the hole 50 into the outer peripheral surface of the first guide 32. In other words, the hole 50 is positioned approximately coaxially with the central axis 44. Multiple connecting rods 30 are connected to the pressing jig 34.

The pressing tool 34 can slide along the outer peripheral surface of the first guide 32. Specifically, the inner wall surface 52 of the pressing tool 34 that forms the hole 50 has a tapered surface 54 and a straight surface 56.

The straight surface 56 is formed on a portion of the inner wall surface 52 that is close to the base plate 28. The straight surface 56 extends along the central axis 44. The radius of curvature (inner diameter) of the straight surface 56 is a substantially constant radius of curvature along the central axis 44. The straight surface 56 is in contact with the outer peripheral surface of the first guide 32. In other words, the inner diameter of the straight surface 56 is substantially the same as the outer diameter of the first guide 32.

The tapered surface 54 is formed on the portion of the inner wall surface 52 that is close to the gas sensor 12. The tapered surface 54 is connected to the straight surface 56. The radius of curvature of the tapered surface 54 changes along the central axis 44. Specifically, the radius of curvature of the tapered surface 54 increases as it approaches the gas sensor 12 along the central axis 44 from the straight surface 56. Therefore, the radius of curvature of the tapered surface 54 is largest at the opening end 58 of the pressing jig 34 that is close to the gas sensor 12.

The tapered surface 54 is formed with a plurality of first inclined planes 60 inclined with respect to the central axis 44 (see Figures 1 and 2). The number of first inclined planes 60 formed on the tapered surface 54 is equal to the number of the crimping jigs 38. The first inclined planes 60 are formed on the tapered surface 54 at predetermined angular intervals (equally spaced) around the central axis 44. Each of the first inclined planes 60 is formed from the open end 58 of the pressing jig 34 to the straight surface 56.

The second guide 36 is a cylindrical member. A through hole 62 large enough to insert the gas sensor 12 is formed on the inside of the second guide 36. The second guide 36 is fixed to the first guide 32 by a plurality of screw members 64. The second guide 36 is arranged approximately coaxially with the central axis 44. The second guide 36 is formed with a plurality of guide holes 66 that communicate with the through hole 62. The plurality of guide holes 66 are formed in the second guide 36 in a direction perpendicular to the central axis 44 (radial direction). The plurality of guide holes 66 are formed at predetermined angular intervals (equidistant) around the central axis 44. A recess 68 is formed in the outer circumferential surface of the second guide 36 above the guide hole 66.

The multiple crimping jigs 38 are arranged inside the pressing jig 34 so as to be housed between the tapered surface 54 and the second guide 36. The multiple crimping jigs 38 are arranged at predetermined angular intervals (equally spaced) around the central axis 44 (see FIG. 2). That is, each of the multiple crimping jigs 38 is arranged between a corresponding one of the multiple first inclined planes 60 and the second guide 36.

Specifically, each of the multiple crimping jigs 38 has a base end 70, an extension 72, and two claws 74, 76. The base end 70 has a second inclined plane 78 that is in surface contact with the first inclined plane 60. The second inclined plane 78 is provided with a grease reservoir 80. Grease (not shown) is supplied to the grease reservoir 80. The extension 72 extends from the base end 70 toward the central axis 44. The extension 72 is inserted into a corresponding one of the multiple guide holes 66.

The two claw portions 74, 76 are formed at the tip of the extension portion 72. The two claw portions 74, 76 are provided at a predetermined distance along the central axis 44 at the tip of the extension portion 72. One claw portion 76 is closer to the gas sensor 12 along the central axis 44 than the other claw portion 74. It is desirable that one claw portion 76 protrudes slightly toward the central axis 44 more than the other claw portion 74.

Each of the multiple spring members 40 is interposed between the base end 70 of the corresponding crimping jig 38 among the multiple crimping jigs 38 and the corresponding recess 68 among the multiple recesses 68 of the second guide 36. Each of the multiple spring members 40 biases the corresponding crimping jig 38 so that the corresponding crimping jig 38 moves away from the central axis 44.

Figures 2 to 4 show the configuration of multiple crimping jigs 38. As shown in Figure 2, the crimping device 10 (see Figure 1) has eight crimping jigs 38. The pressing jig 34 has eight first inclined planes 60. The eight first inclined planes 60 are formed at 45° intervals around the central axis 44. Therefore, the eight crimping jigs 38 are arranged at 45° intervals around the central axis 44.

The number of crimping jigs 38 shown in FIG. 2 is an example. In the crimping device 10, two or more crimping jigs 38 may be arranged at equal intervals around the central axis 44. For example, four or five crimping jigs 38 may be arranged at equal intervals around the central axis 44.

As shown in FIG. 3, the two claws 74, 76 of the crimping jig 38 are formed in an arc shape in a plan view. This allows each of the two claws 74, 76 to come into surface contact with the cylindrical body 14 of the gas sensor 12 (see FIG. 1).

As shown in FIG. 4, the grease reservoir 80 is a rectangular slit provided in the second inclined plane 78.

Next, the method of crimping the gas sensor 12 using the crimping device 10 will be described with reference to Figures 1 and 5 to 8.

First, as shown in FIG. 5, the gas sensor 12 is placed above the crimping device 10. In this case, the tip of the gas sensor 12 is aligned with the through hole 62 of the second guide 36 so that the central axis 42 of the gas sensor 12 and the central axis 44 of the crimping device 10 are substantially coaxial.

Next, as shown in FIG. 6, the gas sensor 12 is inserted into the first guide 32 in the direction of arrow A along the central axis 42 (central axis 44). In this case, the gas sensor 12 is inserted into the first guide 32 so that the base end 22 of the tubular body 14 faces the two claws 74, 76 of each of the multiple crimping jigs 38. Note that the crimping device 10 can also insert the gas sensor 12 into the first guide 32 by using a retraction mechanism (not shown) to grasp the screw nut 20 of the gas sensor 12 and retract the gas sensor 12 to a predetermined position inside the first guide 32.

Next, as shown in FIG. 7, the driving source is driven to move (raise) the connecting plate 26 in the direction of arrow B toward the gas sensor 12. As described above, the pressing tool 34 is connected to the connecting plate 26 via multiple connecting rods 30. Therefore, as the connecting plate 26 rises, the pressing tool 34 slides (rises) in the direction of arrow B along the outer circumferential surface of the first guide 32.

The second inclined plane 78 of each of the multiple crimping jigs 38 is in surface contact with the first inclined plane 60 of the pressing jig 34. As the pressing jig 34 rises, the base end portion 70 of each of the multiple crimping jigs 38 slides on the corresponding first inclined plane 60. Specifically, as the pressing jig 34 rises, the base end portion 70 slides on the first inclined plane 60 so as to descend toward the straight surface 56. As a result, the extension portion 72 connected to the base end portion 70 moves in the direction of arrow C toward the base end portion 22 of the cylindrical body 14 against the biasing force of the spring member 40.

When the pressing tool 34 is further raised, the two claws 74, 76 of each of the multiple crimping tools 38 come into contact with the base end 22 of the cylindrical body 14. The two claws 74, 76 press the base end 22 and grommet 16 of the cylindrical body 14 radially inward of the cylindrical body 14. This causes the base end 22 and grommet 16 of the cylindrical body 14 to be crimped, forming the crimped portion 24. As a result, the inside of the gas sensor 12 becomes airtight. Note that if the claws 76 protrude toward the central axis 44 beyond the claws 74, the portion of the crimped portion 24 pressed by the claws 76 is crimped radially inward of the cylindrical body 14 relative to the portion pressed by the claws 74.

After the crimped portion 24 is formed, as shown in FIG. 8, the driving source is driven to lower the connecting plate 26 in the direction of arrow D. The pressing jig 34 is connected to the connecting plate 26 via multiple connecting rods 30, so it slides (lowers) in the direction of arrow D along the outer circumferential surface of the first guide 32.

As the pressing tool 34 descends, the base end 70 of each of the multiple crimping tools 38 slides along the first inclined plane 60. Specifically, as the pressing tool 34 descends, the base end 70 slides along the first inclined plane 60 so as to approach the open end 58. In this case, the spring member 40 applies a biasing force to the base end 70 such that the base end 70 moves away from the central axis 44. Therefore, the extension 72 connected to the base end 70 moves away from the cylindrical body 14 in the direction of arrow E due to the sliding of the base end 70 and the biasing force of the spring member 40. As a result, the crimping portion 24 of the gas sensor 12 is released from the pressed state by the two claws 74, 76.

When the pressing tool 34 is further lowered, the base end 70 of each of the multiple crimping tools 38 slides close to the opening end 58 of the first inclined plane 60. This causes the two claws 74, 76 to retreat to the guide hole 66.

Next, as shown in FIG. 1, raise the gas sensor 12 in the direction of arrow F and remove the gas sensor 12 from the crimping device 10.

The present invention is not limited to the above-described embodiment, and various configurations may be adopted without departing from the gist of the present invention.

The invention that can be understood from the above embodiment is described below.

The present invention relates to a gas sensor crimping device (10) that includes a plurality of crimping jigs (38) arranged around the axis of a gas sensor (12) that extends along the axial direction and for crimping the gas sensor, and a pressing jig (34) that moves along the axial direction to press the plurality of crimping jigs against the gas sensor, in which a hole (50) is formed in the pressing jig to accommodate the gas sensor and the plurality of crimping jigs, and the inner wall surface (52) of the pressing jig that forms the hole has a plurality of first inclined planes (60) that are inclined with respect to the axis line (42) of the gas sensor in order to press each of the plurality of crimping jigs against the gas sensor, and each of the plurality of crimping jigs has a second inclined plane (78) that is in surface contact with a corresponding one of the plurality of first inclined planes.

In the present invention, the second inclined plane of each of the multiple crimping jigs is in surface contact with the corresponding first inclined plane. As a result, when the crimping jig slides along the first inclined plane, the first inclined plane and the second inclined plane are in smooth surface contact over the entire surface of the first inclined plane. As a result, the variation in the crimping load can be reduced.

In this aspect of the present invention, the first inclined planes are inclined planes that approach the gas sensor as they advance further into the pressing jig.

This makes it possible to further reduce variation in the crimping load and crimp the gas sensor with high precision.

In one aspect of the present invention, a grease reservoir (80) is provided on the second inclined plane of each of the multiple crimping jigs.

This allows grease to be efficiently supplied from the grease reservoir to the first and second inclined planes, improving the sliding between the first and second inclined planes. As a result, it is possible to reduce the variation in the crimping load caused by wear of the pressing tool and the crimping tool and the sliding load on the first and second inclined planes.

In this aspect of the present invention, the multiple first inclined planes are arranged at equal intervals around the axis of the gas sensor, and each of the multiple crimping jigs is arranged at equal intervals around the axis of the gas sensor so that the second inclined plane is in surface contact with the corresponding first inclined plane.

This allows the contact position of the crimping jig with the gas sensor and the contact friction force of the crimping jig with the gas sensor to be approximately equal among multiple crimping jigs. As a result, the variation in the crimping load can be further reduced.

In this aspect of the present invention, the crimping device further includes a plurality of spring members (40) that bias the plurality of crimping jigs so that the plurality of crimping jigs move away from the gas sensor.

This allows the clamping tool to be quickly separated from the gas sensor after the gas sensor is clamped.

10... Crimping device (gas sensor crimping device)
12... Gas sensor 34... Pressing jig 38... Crimping jig 42... Central axis (axis line)
50... Hole 52... Inner wall surface 60... First inclined plane 78... Second inclined plane

Claims (5)

A gas sensor crimping device comprising: a plurality of crimping jigs arranged around an axis of a gas sensor extending along an axial direction, for crimping the gas sensor; and a pressing jig moving along the axial direction to press the plurality of crimping jigs against the gas sensor,
The pressing jig is formed with a hole for accommodating the gas sensor and the plurality of crimping jigs,
an inner wall surface of the pressing jig that forms the hole has a plurality of first inclined planes that are inclined with respect to an axis of the gas sensor in order to press each of the plurality of crimping jigs against the gas sensor;
A gas sensor crimping device, wherein each of the plurality of crimping jigs has a second inclined plane that is in surface contact with a corresponding one of the plurality of first inclined planes. 2. The gas sensor crimping device according to claim 1,
The first inclined planes are inclined planes that approach the gas sensor as they advance toward the inside of the pressing jig. 3. The gas sensor crimping device according to claim 1,
A crimping device for a gas sensor, wherein a grease reservoir is provided on the second inclined plane of each of the plurality of crimping jigs. The gas sensor crimping device according to any one of claims 1 to 3,
The first inclined planes are arranged at equal intervals around an axis of the gas sensor,
A gas sensor crimping device, wherein each of the plurality of crimping jigs is disposed at equal intervals around the axis of the gas sensor so that the second inclined plane is in surface contact with the corresponding first inclined plane. The gas sensor crimping device according to any one of claims 1 to 4,
The gas sensor crimping device further comprises a plurality of spring members that bias the plurality of crimping jigs so as to move the plurality of crimping jigs away from the gas sensor.

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