JP2013257103A - Method and apparatus for manufacturing glow plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately align the axis with the central axis of a heater member when press-fitting the heater member in the housing, thereby effectively suppress the deformation of a tube.SOLUTION: A glow plug 1 includes a cylindrical housing 2 having an axis hole 4 extending in the direction of an axis CL1, a cylindrical tube 7, a heating coil 8 placed in a tube 7, and a heater member 3 press-fitted in the axis hole 4 of the housing 2. When the heater member 3 is press-fitted in the housing 2, the outer periphery of the heater member 3 is supported as the outer periphery of the housing 2 is held by a housing holding part 122 disposed on the outer periphery of the housing 2.

Description

  The present invention relates to a method for manufacturing a glow plug used in an internal combustion engine or the like, and an apparatus for manufacturing a glow plug.

  A glow plug used for starting assistance of a diesel engine includes a housing having a shaft hole extending in the axial direction, and a heater member that is inserted into the shaft hole with its front end protruding from the front end of the housing and generates heat when energized. And. Moreover, as a heater member, the sheath heater provided with the cylindrical tube with which the front-end | tip part closed and the heat generating coil arrange | positioned inside the said tube may be used. When such a sheath heater is used, the heater member (sheath heater) may be fixed to the housing by being press-fitted into the shaft hole of the housing.

  Conventionally, as a method of press-fitting a heater member into a housing, a heater member is set in a shaft hole on one end side of the housing, and then an axial load is applied to the distal end portion of the heater member (tube) to the housing. And a method of press-fitting a heater member is known. However, in this method, when the pressure is locally applied to the tip of the tube, the tip of the tube is crushed and deformed, or when the load is applied, the axial center portion of the tube is bent and deformed. There is a risk.

  Therefore, a technique has been proposed in which the outer periphery of the tube is clamped by a predetermined collet when the heater member is press-fitted into the housing, thereby preventing the tube from being bent and deformed while preventing pressure from being applied to the distal end portion of the tube. (For example, refer patent document 1 etc.).

JP-A-11-94254

  By the way, due to manufacturing errors, there is a slight variation in the formation position of the central axis of the shaft hole and the heater member. May become larger. In such a case, when the heater member is press-fitted into the housing, the press-fitting load of the heater member against the housing also becomes large. Therefore, even if the above technique is used, the tube may be deformed when the heater member is pressed into the housing.

  In recent years, in order to reduce the size (diameter) of the glow plug, it is required to reduce the diameter of the heater member (tube). In such a heater member having a reduced diameter, the heater member is pressed into the housing. There is more concern about the deformation of the tube.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to more reliably match the axis and the center axis of the heater member when the heater member is press-fitted into the housing, and to effectively deform the tube. It is an object of the present invention to provide a method for manufacturing a glow plug and an apparatus for manufacturing a glow plug that can be suppressed.

  Hereinafter, each configuration suitable for solving the above-described object will be described in terms of items. In addition, the effect specific to the corresponding structure is added as needed.

Configuration 1. A manufacturing method of the glow plug of this configuration includes a cylindrical housing having an axial hole extending in the axial direction;
A glow plug manufacturing method comprising a tubular tube, and a heater member disposed inside the tube, the heater member being press-fitted into the shaft hole of the housing,
Including a press-fitting step of press-fitting the heater member into the housing;
In the press-fitting step,
While holding the outer periphery of the heater member,
The outer periphery of the housing is held by a housing holding portion provided on the outer peripheral side of the housing.

  Note that “holding the outer periphery of the heater member” is not only the case where the heater member is held in a state where it cannot be moved along its radial direction, but the heater member can be moved slightly along its radial direction. Including the case of holding in a state. “Holding the outer periphery of the housing” means not only when the housing is held in a state where it cannot move along its radial direction, but also when the housing is held so as to be slightly movable along its radial direction. (Including the same).

  According to the configuration 1, the outer periphery of the heater member and the outer periphery of the housing are held in the press-fitting step. Therefore, the axial deviation between the axis and the central axis of the heater member can be more reliably suppressed, and the press-fit load when the heater member is press-fitted into the housing can be further reduced. As a result, deformation of the tube during press-fitting can be effectively suppressed, and productivity (yield) can be improved.

  Configuration 2. The glow plug manufacturing method according to this configuration is characterized in that, in the above configuration 1, the holding force of the housing by the housing holding portion is determined based on a press-fit load of the heater member to the housing along the axis. And

  From the viewpoint of improving the appearance quality, corrosion resistance, and attachment to the engine head, it is preferable to prevent the outer periphery of the housing from being wrinkled as much as possible. Therefore, in view of this point, the holding force when holding the outer periphery of the housing by the housing holding portion is reduced (for example, the housing holding portion is located in the vicinity of the outer periphery of the housing and lightly contacts the outer periphery of the housing, or It is preferable that the degree of contact is almost not in contact. On the other hand, when the amount of axial deviation between the axis and the central axis of the heater member is relatively large and the press-fitting load is large, the holding force is increased so that the axis is aligned between the axis and the central axis. It is preferable to further enhance the effect and to further reduce the press-fit load.

  In this regard, the configuration 2 is configured such that the holding force of the housing by the housing holding portion is determined based on the press-fit load of the heater member to the housing. Therefore, when the press-fitting load is relatively small and the deformability of the tube at the time of press-fitting is relatively low, by reducing the holding force, there is a wrinkle on the outer periphery of the housing while sufficiently suppressing the deformation of the tube. It can be prevented more reliably. Also, when the press-fit load is relatively large and the deformability of the tube at the time of press-fitting is relatively high, the axis can be aligned with the center axis of the heater member more accurately by increasing the holding force. The deformation of the tube can be suppressed very effectively. That is, according to the said structure 2, the deformation | transformation of the tube at the time of press fit can be suppressed effectively, preventing a wrinkle on the outer periphery of a housing as much as possible. As a result, the productivity can be further improved.

  Configuration 3. The glow plug manufacturing method of this configuration is characterized in that, in the above configuration 1 or 2, at least a portion of the housing holding portion that holds the outer periphery of the housing is made of at least one of resin and rubber.

  According to the configuration 3, the portion of the housing holding portion that holds the housing is formed of at least one of resin and rubber, that is, a relatively soft material. Accordingly, it is possible to more reliably prevent the outer periphery of the housing from being wrinkled as the housing is held by the housing holding portion. As a result, productivity can be further improved.

Configuration 4. The glow plug manufacturing apparatus of this configuration includes a cylindrical housing having an axial hole extending in the axial direction;
A glow plug manufacturing apparatus comprising a cylindrical tube, and a heater member disposed inside the tube, the heater member being press-fitted into the shaft hole of the housing,
A press-fitting portion for press-fitting the heater member into the housing by applying a load along the axis to at least one of the housing and the heater member;
A heater member holding portion capable of holding an outer periphery of the heater member when the heater member is press-fitted into the housing;
And a housing holding portion capable of holding the outer periphery of the housing when the heater member is press-fitted into the housing.

  According to the said structure 4, the effect similar to the said structure 1 will be show | played.

Configuration 5. The glow plug manufacturing apparatus of the present configuration, in the configuration 4, the load detection unit for detecting the press-fit load of the heater member with respect to the housing along the axis,
And a holding force determining unit that determines a holding force of the housing by the housing holding unit based on the press-fit load detected by the load detecting unit.

  According to the said structure 5, the effect similar to the said structure 2 will be show | played.

  Configuration 6. The glow plug manufacturing apparatus of this configuration is characterized in that, in the above configuration 4 or 5, at least a portion of the housing holding portion that holds the outer periphery of the housing is made of at least one of resin and rubber.

  According to the configuration 6, the same function and effect as those of the configuration 3 are achieved.

(A) is a partially broken front view of the glow plug, and (b) is an enlarged cross-sectional view of the tip portion of the glow plug. It is the schematic which shows the structure of the manufacturing apparatus used in a press injection process. It is the schematic which shows one process of a press-fit process.

  Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1A is a partially cutaway front view of the glow plug 1, and FIG. 1B is a partially enlarged cross-sectional view of the tip portion of the glow plug 1. 1 and the like, the direction of the axis CL1 of the glow plug 1 will be described as the vertical direction in the drawing, the lower side will be described as the front end side of the glow plug 1, and the upper side will be described as the rear end side.

  As shown in FIGS. 1A and 1B, the glow plug 1 includes a cylindrical housing 2 and a heater member 3 fixed to the housing 2 in a state where the tip end of the glow plug 1 protrudes from the tip of the housing 2. And.

  The housing 2 has a shaft hole 4 extending in the direction of the axis CL1, and a tool having a hexagonal cross section for engaging a screw portion 5 for attachment to a diesel engine and a tool such as a torque wrench on the outer peripheral surface thereof. An engaging portion 6 is formed. In the present embodiment, the housing 2 has a small diameter so that the glow plug 1 can be reduced in size (smaller diameter). As a result, the maximum outer diameter of the small diameter portion 7A of the tube 7 described later is relatively small (for example, 4 mm or less).

  The heater member 3 is made of a predetermined metal (for example, a metal containing Fe or Ni as a main component) and has a tubular tube 7 with a closed tip, a heating coil 8 provided in the tube 7, and A control coil 9 is provided, and a central shaft 10 that forms an energization path to both the coils 8 and 9 is connected.

  The heating coil 8 is connected in series with the control coil 9, and its tip is joined to the tip of the tube 7. The heating coil 8 is configured by spirally winding a resistance heating wire made of a predetermined metal (for example, an alloy containing Fe as a main component and containing Al, Cr, or the like).

  The control coil 9 is provided between the heat generating coil 8 and the middle shaft 10 and has a material having a temperature coefficient of electric specific resistance larger than that of the heat generating coil 8 (for example, Co represented by Co—Ni—Fe alloy). Alternatively, a resistance heating wire made of a metal containing Ni as a main component is spirally wound. Thereby, the control coil 9 increases the electric resistance value by receiving its own heat generation and heat generation from the heat generation coil 8, and controls the power supplied to the heat generation coil 8. More specifically, relatively large electric power is supplied to the heating coil 8 at the initial stage of energization, and the temperature of the heating coil 8 rises rapidly. Then, the control coil 9 is heated by the heat generation and the heat generation of itself, the electric resistance value of the control coil 9 increases, and the power supplied to the heat generation coil 8 decreases. As a result, the temperature rise characteristic of the heater member 3 becomes a form in which, after the temperature is rapidly raised in the initial stage of energization, the supply power is suppressed by the action of the control coil 9 and the temperature is saturated. In other words, the presence of the control coil 9 is configured to prevent the overheating (overshoot) of the heating coil 8 from occurring while increasing the rapid temperature rising property.

  The middle shaft 10 is made of a predetermined conductive metal and has a rod shape extending along the direction of the axis CL1. Further, the front end portion of the middle shaft 10 is inserted into the tube 7 and joined to the rear end portion of the control coil 9, and the rear end portion protrudes from the rear end of the housing 2. At the rear end of the housing 2, an O-ring 13 made of rubber or the like, an insulating bush 14 made of resin or the like, a pressing ring 15 for preventing the insulating bush 14 from falling off, and a cable for connecting an energizing cable. The nut 16 is structured to be fitted into the middle shaft 10 in this order.

  Furthermore, an insulating powder 11 mainly composed of magnesium oxide (MgO) is enclosed in the tube 7, and the insulating powder 11 is interposed so that the outer peripheral surfaces of the heat generating coil 8 and the control coil 9 and the tube 7. The inner peripheral surface is insulated. In addition, the rear end of the tube 7 is sealed with an annular rubber 12 between the tube 7 and the center shaft 8.

  In addition, the tube 7 is formed with a small-diameter portion 7A that accommodates the heating coil 8 or the like at the distal end thereof by swaging or the like, and its outer diameter is smaller than the outer diameter of the small-diameter portion 7A at the rear end portion. The large-diameter portion 7B is also formed. Further, the shaft hole 4 is formed with a small diameter portion 4A having a relatively small inner diameter, and the heater member 3 is formed by press-fitting the large diameter portion 7B into the small diameter portion 4A of the housing 2. 2 is fixed.

  Next, a method for manufacturing the above-described glow plug 1 will be described. In addition, a conventionally well-known method is employ | adopted about the site | part which is not specified clearly.

  First, a resistance heating wire whose main component is Fe or the like is processed into a coil shape to manufacture a heating coil 8, and a resistance heating wire whose main component is Co or the like is processed into a coil shape to manufacture a control coil 9. . Further, a cylindrical tube 7 whose tip is not closed is manufactured using a metal material mainly composed of Ni or Fe.

  Next, the heating coil 8, the control coil 9, and the middle shaft 10 are joined in series. Then, the tip of the middle shaft 10 and the heating coil 8 and the control coil 9 integrated with the middle shaft 10 are arranged in the cylindrical tube 7. Thereafter, the tip of the tube 7 is closed by arc welding or the like, and the tip of the tube 7 and the tip of the heating coil 8 are joined.

  Next, the tube 7 is filled with the insulating powder 11, and the annular rubber 12 is provided between the rear end opening of the tube 7 and the center shaft 10 to seal the inside of the tube 7. Thereafter, swaging is applied to the distal end portion of the tube 7, and the distal end portion of the tube 7 is reduced in diameter to form the small diameter portion 7 </ b> A. Thereby, the heater member 3 integrated with the center shaft 10 is obtained.

  Next, in the press-fitting step, the heater member 3 formed as described above is press-fitted into the shaft hole 4 of the housing 2. Here, when press-fitting the heater member 3 into the housing 2, as shown in FIG. 2, a first jig 110 for supporting the heater member 3, a second jig 120 for supporting the housing 2, and a predetermined jig A manufacturing apparatus 100 including a holding force determination unit 130 configured by an electronic control device or the like is used.

  The first jig 110 includes an insertion portion 110A that extends along the vertical direction and through which the heater member 3 is inserted. The first jig 110 supports the heater member 3 in a state where the heater member 3 is inserted through the insertion portion 110A. . The first jig 110 includes a cylindrical heater member holding portion 111 that can move in the radial direction. The heater member holding portion 111 is configured to be able to increase or decrease its own inner diameter by moving along the radial direction. In addition, the heater member holding portion 111 can hold the outer periphery of the heater member 3 on its inner periphery, and the heater member 3 moves along the radial direction by holding the outer periphery of the heater member 3. To regulate.

  The “holding of the heater member 3 by the heater member holding portion 111” is not only the case where the heater member holding portion 111 is in contact with the outer periphery of the heater member 3, but the heater member holding portion 111 is The case where it arrange | positions in the state which does not contact the heater member 3 in the outer periphery vicinity is also included. That is, “holding the heater member 3 by the heater member holding portion 111” is not only the case where the heater member 3 is held in a state where it cannot move along the radial direction, but also the heater member 3 in the radial direction. It also includes the case where it is held in a state where it can move only slightly (for example, about 0.2 mm along the radial direction).

  The second jig 120 is disposed on the upper side of the first jig 110 and can be applied with a load along the vertical direction by a press-fit portion 140 (for example, a servo press) that can move along the vertical direction. Thus, the first jig 110 can be moved closer to the first jig 110. The second jig 120 has a through-hole 121A extending along the vertical direction, a cylindrical insertion support portion 121 that supports the housing 2 in a state where the housing 2 is inserted through the through-hole 121A, and a diameter. And a housing holding part 122 movable in the direction.

  The housing holding part 122 is configured to be able to increase or decrease its own inner diameter by moving along the radial direction. The housing holding portion 122 is a portion of the housing 2 on the tip end side of the screw portion 5 in the inner periphery of the housing 2 (a portion that should particularly prevent adhesion of wrinkles in terms of corrosion resistance, attachment to the engine head, etc. ) And the movement of the housing 2 along its radial direction is restricted by holding the outer periphery of the housing 2. In addition, in this embodiment, at least one of resin and rubber (for example, 66 nylon, silicone rubber, fluoro rubber) is used as the inner peripheral portion 122A that is a portion that holds at least the outer periphery of the housing 2 in the housing holding portion 122. Etc.).

  The “holding of the housing 2 by the housing holding portion 122” is not only the case where the housing holding portion 122 contacts the outer periphery of the housing 2, but the housing holding portion 122 is connected to the housing 2 in the vicinity of the outer periphery of the housing 2. Including the case where it is arranged with almost no contact. That is, “holding the housing 2 by the housing holding portion 122” is not only when the housing 2 is held in a state in which the housing 2 is immovable along the radial direction, but the housing 2 is slightly moved along the radial direction ( (For example, about 0.2 mm along the radial direction) including the case of holding in a movable state. In addition, changing the holding state of the housing 2 in this way is performed by adjusting the holding force of the housing 2 by the housing holding portion 122. Then, the holding force of the housing 2 by the housing holding portion 122 is determined by the holding force determining portion 130.

  The holding force determination unit 130 is based on a press-fit load along the axis CL1 when the heater member 3 is press-fitted into the housing 2 detected by a load detection unit 141 formed of a load cell or the like provided in the press-fit unit 140. Thus, the holding force of the housing 2 by the housing holding part 122 is determined. In the present embodiment, when the detected press-fit load is equal to or less than a predetermined load set in advance, the holding force is set to a relatively small constant value, and the housing holding portion 122 is located near the outer periphery of the housing 2. It is arranged in a state where there is almost no contact. On the other hand, when the detected press-fit load exceeds the predetermined load, the housing holding portion 122 contacts the outer periphery of the housing 2 and the holding force is increased as the press-fit load is increased. That is, the greater the detected press-fit load, the more reliably the movement of the housing 2 along the radial direction is regulated.

  Returning to the description of the manufacturing method, when the heater member 3 is press-fitted into the housing 2, first, the heater is placed below the housing 2 so that the axis CL 1 of the shaft hole 4 and the center axis of the heater member 3 substantially coincide with each other. The member 3 is disposed. After that, the second jig 120 is moved closer to the first jig 110 by the press-fitting portion 140 and a load along the direction of the axis CL1 is applied to the housing 2, whereby the shaft hole 4 of the housing 2 is applied. The heater member 3 (large diameter portion 7B) is press-fitted inside (small diameter portion 4A). It should be noted that there may be variations in the positions of the axis CL1 and the central axis of the heater member 3 due to errors in manufacturing. Therefore, even when the heater member 3 is arranged below the housing 2 so that the axis CL1 and the central axis of the heater member 3 are substantially coincident with each other, there is no gap between the axis CL1 and the central axis of the heater member 3. Some axial misalignment can occur. Here, since the press-fitting load increases as the amount of axial deviation increases, the tube 7 is more likely to be deformed during press-fitting.

  Therefore, in the present embodiment, as shown in FIG. 3, when the heater member 3 is press-fitted into the housing 2, the outer periphery of the heater member 3 is held by the heater member holding portion 111 and the housing 2 is held by the housing holding portion 122. Is held. Thereby, at the time of press-fitting, the amount of axial deviation between the axis line CL1 and the central axis of the heater member 3 can be made smaller, and the press-fitting load can be reduced.

  After press-fitting the heater member 3 into the housing 2, the holding force of the heater member holding portion 111 and the housing 122 is released, and then the housing 2 to which the heater member 3 is fixed is removed from the insertion support portion 121.

  Finally, the above-described glow plug 1 is obtained by fitting the O-ring 13, the insulating bush 14, and the like into the middle shaft 10 at the rear end portion of the housing 2.

  As described above in detail, according to the present embodiment, the outer periphery of the heater member 3 and the outer periphery of the housing 2 are held in the press-fitting process. Therefore, the axial shift between the axis line CL1 and the central axis of the heater member 3 can be more reliably suppressed, and the press-fitting load when the heater member 3 is press-fitted into the housing 2 can be further reduced. As a result, deformation of the tube 7 during press-fitting can be effectively suppressed, and productivity (yield) can be improved.

  In particular, as in this embodiment, when the tube 7 has a small diameter, the tube 7 is more likely to be deformed in the press-fitting process. However, by adopting the above-described configuration, the tube 7 has a small diameter. Also, the deformation of the tube 7 can be effectively suppressed. In addition, when the tube 7 has the small diameter portion 7A and the large diameter portion 7B as in the present embodiment, buckling deformation occurs in the connecting portion between the small diameter portion 7A and the large diameter portion 7B in the press-fitting process. Although there is a concern, by adopting the above-described configuration, such a concern can be eliminated.

  Further, in the present embodiment, the holding force of the housing 2 by the housing holding portion 122 is determined based on the press-fit load of the heater member 3 with respect to the housing 2, and when the press-fit load is relatively small When the holding force is small and the press-fitting load is relatively large, the holding force is large. Therefore, when the press-fitting load is small and the deformability of the tube 7 at the time of press-fitting is relatively low, it is possible to more reliably prevent the outer periphery of the housing 2 from being wrinkled while sufficiently suppressing the deformation of the tube 7. it can. On the other hand, when the press-fitting load is relatively large and the deformability of the tube 7 at the time of press-fitting is relatively high, the axis line CL1 and the central axis of the heater member 3 can be aligned more accurately, and the tube 7 can be deformed. Can be suppressed very effectively. That is, according to the present embodiment, deformation of the tube 7 at the time of press-fitting can be effectively suppressed while preventing wrinkles on the outer periphery of the housing 2 as much as possible. As a result, the productivity can be further improved.

  In addition, the inner peripheral portion 122A that holds the outer periphery of the housing 2 in the housing holding portion 122 is formed of at least one of resin and rubber, that is, a relatively soft material. Accordingly, it is possible to more reliably prevent the outer periphery of the housing 2 from being wrinkled as the housing 2 is held by the housing holding portion 122. As a result, productivity can be further improved.

  In addition, it is not limited to the description content of the said embodiment, For example, you may implement as follows. Of course, other application examples and modification examples not illustrated below are also possible.

  (A) The shape of the glow plug 1 is not limited to the above embodiment. For example, the tube 7 is configured so that the large-diameter portion 7B is omitted and the outer diameter is a straight shape with a substantially constant shape. Also good. The small diameter portion 4A of the shaft hole 4 may be omitted, and the heater member 3 may be press-fitted into the shaft hole 4 of the housing 2 that has a straight shape in the direction of the axis CL1.

  (B) In the above embodiment, the glow plug 1 has the control coil 9, but the control coil 9 may be omitted and the rear end of the heating coil 8 may be directly joined to the middle shaft 10.

  (C) In the embodiment described above, a metal mainly composed of Fe or Ni is cited as the metal material constituting the tube 7, but this is an example, and the metal material constituting the tube 7 is limited to this. Is not to be done. Moreover, although the metal which has Fe etc. as a main component is mentioned as a metal material which comprises the heating coil 8 and the control coil 9, the constituent material of the heating coil 8 etc. is not limited to this.

  (D) In the above embodiment, the second jig 120 moves closer to the first jig 110, and a load along the axis CL <b> 1 is applied to the housing 2, so that the heater member is applied to the housing 2. 3 is press-fitted. On the other hand, the first jig 110 moves closer to the second jig 120, and a load along the axis CL1 is applied to the heater member 3, whereby the heater member 3 is moved relative to the housing 2. It is good also as press-fitting. Further, the heater member 3 may be press-fitted into the housing 2 by applying a load along the axis CL <b> 1 to both the housing 2 and the heater member 3.

  DESCRIPTION OF SYMBOLS 1 ... Glow plug, 2 ... Housing, 3 ... Heater member, 4 ... Shaft hole, 7 ... Tube, 8 ... Heat generating coil, 100 ... Manufacturing apparatus, 111 ... Heater member holding part, 122 ... Housing holding part, 130 ... Holding force Determining unit, 140 ... press-fitting unit, 141 ... load detecting unit, CL1 ... axis.

Claims (6)

A cylindrical housing having an axial hole extending in the axial direction;
A glow plug manufacturing method comprising a tubular tube, and a heater member disposed inside the tube, the heater member being press-fitted into the shaft hole of the housing,
Including a press-fitting step of press-fitting the heater member into the housing;
In the press-fitting step,
While holding the outer periphery of the heater member,
A method for manufacturing a glow plug, wherein an outer periphery of the housing is held by a housing holding portion provided on an outer peripheral side of the housing.   The method for manufacturing a glow plug according to claim 1, wherein a holding force of the housing by the housing holding portion is determined based on a press-fit load of the heater member to the housing along the axis.   The method for manufacturing a glow plug according to claim 1, wherein at least a portion of the housing holding portion that holds the outer periphery of the housing is made of at least one of resin and rubber. A cylindrical housing having an axial hole extending in the axial direction;
A glow plug manufacturing apparatus comprising a cylindrical tube, and a heater member disposed inside the tube, the heater member being press-fitted into the shaft hole of the housing,
A press-fitting portion for press-fitting the heater member into the housing by applying a load along the axis to at least one of the housing and the heater member;
A heater member holding portion capable of holding an outer periphery of the heater member when the heater member is press-fitted into the housing;
A glow plug manufacturing apparatus, comprising: a housing holding portion capable of holding an outer periphery of the housing when the heater member is press-fitted into the housing. A load detection unit that detects a press-fit load of the heater member with respect to the housing along the axis;
The glow plug manufacturing apparatus according to claim 4, further comprising a holding force determining unit that determines a holding force of the housing by the housing holding unit based on a press-fit load detected by the load detecting unit. .   The glow plug manufacturing apparatus according to claim 4 or 5, wherein at least a portion of the housing holding portion that holds the outer periphery of the housing is made of at least one of resin and rubber.

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