JPH0932587A - Fuel injection timing control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection timing control device by which the number of part items can be reduced and installing manhours can be reduced. SOLUTION: Sliding plates (48a and b) positioned around a piston pin 41 are respectively formed in a shape by dividing a cylinder in the radial direction, and its inner wall is formed as a recessed spherical surface which can come into surface contact with a spherical surface being an outer wall of a spherical surface part of the piston pin 41. Outer peripheral walls of the sliding plates (48a and b) are formed as a recessed curved surface which can come into surface contact with an inner wall of a cylindrical hole part of a timer piston 42. The central axis A of a circle drawn along the outer periphery of the sliding plates (48a and b) and the central axis B of the spherical part 41b of the piston pin 41 are made eccentric so as not to be positioned on the same axis. Therefore, since respective thicknesses of the sliding plates (48a and b) can be differently set, a peripheral directional movement of the sliding plates (48a and b) can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection timing control device.

[0002]

2. Description of the Related Art In a conventional distribution type fuel injection pump, for example, an inner cam type pump, when a rotor rotates while slidingly contacting a cylinder and a distribution port formed in the rotor communicates with a distribution passage of the cylinder. The fuel pressurized by the plunger is supplied from the distribution port to the diesel engine (hereinafter referred to as "engine") through the distribution passage and the delivery valve. In such a distributed fuel injection pump, the injection timing of the distributed fuel injection pump is adjusted by giving a phase between the rotation of the drive shaft on the engine side and the rotation of the rotor that rotates in accordance with the rotation of the drive shaft. For this adjustment mechanism, a hydraulic timer unit that operates by fuel pressure in the pump chamber or the like is used.

In this type of hydraulic timer, as shown in FIG. 7, a cylindrical timer having a hole 103 into which the piston pin 108 and the slide plates 104a, 104b can be inserted is formed substantially at the center in the longitudinal direction. Piston 102
Is used as a hydraulic piston. The timer piston 102 is moved in the left-right direction in FIG. 7 due to the balance of pressures in the pressure chambers located at both ends of the timer piston 102, thereby urging the piston pin 108 in the same direction.

[0004]

However, according to the distributed fuel injection pump having such a hydraulic timer unit, the slide plates 104a, 104b located around the piston pin 108 are symmetrical in the radial direction. Since it has a shape in which the cylinder is divided so that the slide plates 104a and 104b can move in the direction indicated by the arrow in FIG. 7, that is, in the circumferential direction of the piston pin 108.
Therefore, the timer piston 102 and the piston pin 1
Slide plate 104 along with the movement of 08 in the left-right direction
a and b gradually move along the circumferential direction of the piston pin 108. When the movement of the slide plates 104a and 104b causes the boundary portion between the slide plates 104a and 104b to be located on the central axis G of the timer piston 102 shown in FIG. The stress concentrates on the end portions of the slide plates 104a and 104b, which are the boundary portions, causing a problem that the slide plates 104a and 104b are deformed.

Therefore, the timer piston 102 shown in FIG.
By providing the detent pin 106 projecting from the side wall of the timer piston 102 into the hole 103 on the central axis H of the piston pin 108 that is orthogonal to the central axis G of, the slide plates 104a, 104b that have moved in the circumferential direction are rotated. The stopper pin 106 is brought into contact with the stopper pin 106 to prevent the movement from continuing. However, the provision of the detent pin 106 causes a problem that the structure of the piston pin 108 becomes complicated and that the number of parts of the timer portion increases. Further, since the force due to the slide plates 104a and 104b coming into contact with each other is applied to the detent pin 106, it is necessary to increase the strength of the detent pin 106. Therefore, there is a problem that the cost is increased due to the use of the metal material having high hardness.

Further, for example, in the fuel injection pump disclosed in Japanese Patent Laid-Open No. 6-200852, a structure in which a coupling member for connecting to a bearing portion inserted in a recess of the pump piston is provided on the cam ring allows the pump piston to move to the cam ring. It is transmitting power. However, since it is difficult to integrally form a spherical or roller-shaped coupling member that radially projects from the cam ring with the cam ring, there is a problem of directly increasing the manufacturing cost.

An object of the present invention is to provide a fuel injection timing control device which reduces the number of parts and the number of assembling steps.

[0008]

The fuel injection timing control device according to claim 1 according to the present invention for solving the above-mentioned problems adjusts the pressure feeding timing of the plunger for feeding the fuel. A fuel injection timing control device for a distributed fuel injection pump for controlling fuel injection timing, comprising a cam member for adjusting the pressure feed timing of the plunger, a hydraulic piston reciprocable by a pressure change in a pressure control chamber, and the hydraulic pressure. Between the piston pin inserted into the through hole of the hydraulic piston from the direction opposite to the cam member of the piston and assembled to the cam member, and the outer peripheral wall of the piston pin located in the through hole and the inner peripheral wall of the through hole. A plurality of plates having an arcuate cross-section, and at least the plurality of plates on a line of action by which the reciprocating motion of the hydraulic piston is transmitted to the piston pin. Either plate is positioned, the circumscribed circle and the inscribed circle in the cross-sectional shape of the plurality of plates, characterized in that the eccentric.

As a result, even if a plurality of plates are going to move along the circumferential direction of the piston pin, the plates move from the leading end in the moving direction to the central part in the circumferential direction or from the central part in the circumferential direction to the rear end in the moving direction. Since it moves toward the gap narrower than those widths, it is possible to prevent the plurality of plates from moving along the circumferential direction of the piston pin. Therefore, it is not necessary to provide, for example, a rotation stop pin or the like for preventing the plurality of plates from moving in the circumferential direction of the piston pin, so that it is possible to reduce the number of parts and the number of assembling steps.

A fuel injection timing control device according to a second aspect of the present invention is the fuel injection timing control device according to the first aspect, wherein the plurality of plates are located on the high pressure side of the pressure control chamber. And a second plate group located on the low-pressure side of the pressure control chamber, and a part of the plurality of plates forming the first plate group constitutes the second plate. The cross-sectional shape is thicker than the rest of the plurality of plates.

Thus, the strength of the plurality of plates can be set so as to withstand the load received by the fuel pressure in the high pressure chamber, the internal pressure of which is higher than that of the low pressure chamber. Therefore, there is an effect of preventing damage to the plurality of plates. Furthermore, a fuel injection timing control device according to a third aspect of the present invention is the fuel injection timing control device according to the first or second aspect, in which the outer peripheral wall of the piston pin located in the through hole and the plurality of plates are arranged. The first contact portion with which the inner peripheral wall contacts each other is a surface contact or a line contact, and the second contact portion with which the outer peripheral walls of the plurality of plates and the inner peripheral wall of the through hole of the hydraulic piston contact each other. Surface contact or line contact, and at least one of the first contact portion and the second contact portion is in contact with a spherical surface.

As a result, the pressure applied to the contact portion can be reduced as compared with the case where the first contact portion or the second contact portion is in point contact. Therefore, when the hydraulic piston reciprocates due to the pressure change in the pressure control chamber, the piston pin can be smoothly moved. Furthermore, a fuel injection timing control device according to a fourth aspect of the present invention is the fuel injection timing control device according to the third aspect, wherein the center of the spherical surface is eccentric with respect to the central axis of the hydraulic piston. Characterize.

Accordingly, the center of the spherical surface, which is the contact surface of the first contact portion or the second contact portion, is not located on the central axis of the hydraulic piston, so that the rotation of the hydraulic piston in the circumferential direction can be prevented. Therefore, it is possible to prevent the hydraulic piston and the piston pin from coming into contact with each other, which is caused by, for example, the circumferential rotation of the hydraulic piston.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment in which the fuel injection timing control device of the present invention is applied to a distributed fuel injection pump. As shown in FIG. 2, a drive shaft 1 of a distributed fuel injection pump (hereinafter referred to as “injection pump”) 10 driven by an engine (not shown) has a pump housing 3 via an oil seal 2 and a drive shaft journal bearing 2a. It is rotatably supported by. The feed pump 4 rotates integrally with the drive shaft 1, sucks fuel from a fuel tank (not shown) and pressurizes it, and then delivers the fuel to the suction gallery 14 via the feed pump feed pressure chamber 8 and an external pipe (not shown). are doing. The suction gallery 14 is formed in an annular shape on the inner wall of the distribution head 5 fixed to the pump housing 3. The fuel discharge side and the fuel suction side of the feed pump 4 are connected via a pressure adjusting valve (not shown) so that the discharge pressure is adjusted.

A cylinder 6 is fixed to the inner wall of the distribution head 5, and a distribution rotor 13 is rotatably supported on the inner wall of the cylinder 6. The distribution rotor 13 is axially connected to the drive shaft 1 and rotates integrally with the drive shaft 1. The cylinder 6 has an intake passage 15 communicating with the intake gallery 14, a plurality of distribution passages 16 for supplying fuel to each cylinder of the engine, and a spill passage 17. The distribution passage 16 communicates with a plurality of delivery valves 19 for supplying fuel to each cylinder of the engine through a plurality of fuel passages 18 provided in the distribution head 5.

A pair of sliding holes 13a which are orthogonal to each other are formed in the distribution rotor 13, and a pair of plungers 20 are slidably supported in an oil-tight state on the inner wall of the distribution rotor 13 forming the respective sliding holes 13a. And each plunger 2
A plunger chamber 21 is defined by the inner end surface of 0 and the inner wall forming each sliding hole 13a. Distribution rotor 1
3 includes a communication passage 25 that extends axially from the plunger chamber 21 defined on one end side toward the other end side to the central portion.
Is formed, and further extends obliquely outward in the radial direction from the communication passage 25 toward the other end side, whereby the distribution rotor 1 is formed.
A discharge passage 27 opening to the outer wall of No. 3 is formed. The open end of the discharge passage 27 is an outlet for high-pressure fuel and communicates with an annular groove 29 formed on the outer peripheral wall of the distribution rotor 13. Further, a distribution port 26 communicating with the annular groove 29 is formed on the outer wall of the distribution rotor 13. The distribution port 26 is closed by the inner peripheral wall of the cylinder 6 as the distribution rotor 13 rotates, and communicates with the distribution passage 16 described above.

As shown in FIGS. 1 and 2, a shoe 22 is provided at the outer end of each plunger 20 described above.
A roller 23 is rotatably held by each shoe 22. An inner cam ring 24 having a cam surface 24a having a plurality of cam peaks on the inner peripheral surface thereof is arranged outside the roller 23, and the roller 23 moves on the inner peripheral surface of the inner cam ring 24 based on the rotation of the distribution rotor 13. Cam surface 24a
The roller 23 reciprocates in the radial direction of the inner cam ring 24 along the cam surface 24a, and this reciprocation is transmitted to the plunger 20 via the shoe 22. The stroke in which the plunger 20 moves to the outside in the radial direction of the distribution rotor 13 is the suction stroke, and the stroke in which the plunger 20 moves to the inside in the radial direction is the distribution stroke.

The timer section 40 adjusts the injection start position with respect to the crank angle of the engine (not shown) by rotating the inner cam ring 24 in contact with the roller 23. As shown in FIG. 1, the timer piston 42, which drives the piston pin 41 interlocking with the inner cam ring 24 via the slide plates 48a and 48b, is provided in a part of the pump housing 3 located below the inner cam ring 24 in FIG. It is located and is slidably accommodated in the tubular liner 43. The timer piston 42 having a cylindrical shape in which the upper and lower surfaces of the central portion in the axial direction are gently squeezed has a hole 42a formed in the squeezed portion.
The piston pin 41 and the slide plates 48a and 48b described above are housed in the 2a. Therefore, the pump housing 3 is formed with a timer portion chamber 3a which is a cylindrical space portion, and a piston pin insertion hole 3b communicating with the timer portion chamber 3a is provided on the side opposite to the inner cam ring 24 in the central portion of the timer portion chamber 3a in the axial direction. Are formed. Then, the timer chamber 3a and the piston pin insertion hole 3b
A detachable lid portion 47 and a blind plug 49 are attached to the open end of each.

The pressure of the feed pump feed pressure chamber 8 is introduced into the high pressure chamber 44 located at one end of the timer piston 42 via a timer hydraulic pressure supply passage (not shown), and is fed to the low pressure chamber 45 located at the other end. Is a return spring 4 for urging the timer piston 42 toward the retard side which is the high pressure chamber 44 side.
6 is interposed. The high pressure chamber 44 and the low pressure chamber 45 communicate with each other through a passage (not shown), and this passage is throttled by a timing control valve 59 whose duty ratio is controlled by an electronic control unit (not shown).

As a result, the position of the timer piston 42 for adjusting the fuel injection timing is determined by the pressure in the high pressure chamber 44 and the low pressure chamber 4.
It is determined by the balance between the pressure of 5 and the biasing force of the return spring 46. When the pressure in the feed pump feed pressure chamber 8 increases, the timer piston 42 causes the low pressure chamber 45 to move.
When the pressure in the feed pump feed pressure chamber 8 decreases, the timer piston 42 moves to the high pressure chamber 44 side so that the fuel injection timing is retarded.

Here, the piston pin 41, the timer piston 42 and the slide plates 48a, 48b will be described in detail. As shown in FIG. 3, the slide plates 48a and 48b located around the piston pin 41 are each formed in a shape obtained by dividing a cylinder in the radial direction, and the action line of the piston pin 41, that is, the movement of the piston pin 41. The slide plates 48a and 48b are arranged so that the ends thereof are not located on the center line E in the direction. The inner wall is formed as a concave spherical surface capable of making surface contact with a spherical surface which is an outer wall of a spherical surface portion 42b of the piston pin 41 described later. The outer peripheral walls of the slide plates 48a, 48b are formed into concave curved surfaces capable of making surface contact with the inner wall of the cylindrical hole 42a of the timer piston 42. Here, the outer peripheral walls of the slide plates 48a and 48b and the inner wall of the hole 42a are referred to as "second part" in the claims.
Corresponding to the "contact part".

The central axis of a circle drawn along the outer circumference of the slide plates 48a, 48b, that is, the central axis of the hole portion 42a of the timer piston is represented by the symbol A in FIG. 3, and the piston pin 41 will be described later. The central axis of the spherical surface portion 41b is represented by the symbol B in FIG. In this way, the center axis A of the hole 42a and the center axis B of the piston pin 41 are displaced so as not to be coaxially located, that is, the center of the hole 42a and the center of the piston pin 41 are eccentric, so that the piston The thickness of each of the slide plates 48a and 48b located between the pin 41 and the timer piston 42 can be set to be different. That is, as shown in FIGS. 5 and 6, the central axis of the circle drawn along the inner circumference of the slide plates 48a, 48b, that is, the central axis B of the piston pin 41 is lower than the central axis A of the hole 42a, and the low-pressure chamber 45. By moving to the side, the relationship between the thickness d1 of the slide plate 48a and the thickness d2 of the slide plate 48b becomes d1> d.
Can be set to 2. Here, the slide plates 48a, 48b
A circle drawn along the outer circumference of the slide plate corresponds to the "circumscribing circle" described in the claims, and a circle drawn along the inner circumference of the slide plates 48a and 48b is the "internal circle" described in the claims. Equivalent to "tangential circle".

As a result, the slide plates 48a, 48b
5 moves in the direction of the arrow in FIG. 5, that is, in the circumferential direction of the piston pin 41, from the distal end of the slide plate 48a in the moving direction to the central portion in the circumferential direction, or from the central portion of the slide plate 48b to the rear end in the moving direction. Will move towards a gap that is narrower than their width,
This means that the piston pin 41 cannot move in the circumferential direction.
Therefore, even if the timer piston 42 moves in the left-right direction in FIG. 3, the slide plates 48a, 48b do not move in the circumferential direction of the piston pin 41, and the detent pin 106 shown in FIG. 7 is not necessary. The number of parts can be reduced.

Further, as described above, by moving the central axis B of the piston pin 41 from the central axis A of the hole 42a to the low pressure chamber 45 side, the slide plate 48a on the high pressure chamber 44 side slides on the low pressure chamber 45 side. It will be set thicker than the plate 48b. By making the slide plate 48a on the high-pressure chamber 44 side thick as described above, it is possible to set the slide plate 48a to withstand the load applied by the fuel pressure in the high-pressure chamber 44 having an internal pressure higher than that of the low-pressure chamber 45.

As shown in FIG. 4, the piston pin 41 is
The nut portion 41a, the spherical surface portion 41b, the collar portion 41c, and the male screw portion 41d are integrally formed.
The nut portion 41a is located at one end of the piston pin 41, and is formed in a hexagonal column shape so that a tool such as a wrench can be applied when screwing the male screw portion 41d located at the other end. ing. The male screw portion 41d located at the other end is formed with a screw thread that can be fitted into the female screw portion 24b formed on the inner cam ring 24, and is used for assembling the piston pin 41 to the inner cam ring 24. Then, the nut portion 41a and the male screw portion 4
Between 1d, the collar portion 41c is located on the side of the male screw portion 41d, and the spherical portion 41b is located on the side of the nut portion 41a.

The collar portion 41c is formed so that the end surface on the male screw portion 41d side of the collar portion 41c abuts on the inner cam ring 24 when assembled to the inner cam ring 24. A spherical surface portion 41b is located between the flange portion 41c and the nut portion 41a, and when assembled with the timer piston 42 described above as the timer portion 40, the spherical surface portion 41b is located in the hole portion 42a of the timer piston 42. The outer wall of the spherical portion 41b is formed into a substantially spherical shape, and is formed so as to be in surface contact with the inner walls of the slide plates 48a and 48b described above. Here, the outer wall of the spherical surface portion 41b and the inner walls of the slide plates 48a and 48b are the "first portion" described in the claims.
Corresponding to the "contact part".

Thus, the spherical portion 4 of the piston pin 41
By making the contact between 1b and the slide plates 48a, 48b a surface contact or a line contact and the contact between the slide plates 48a, b and a piston pin 41 also a surface contact or a line contact, for example, the contact surface becomes a point contact. It is possible to reduce the pressure applied to the contact portion as compared with other cases. Therefore, when the timer piston 42 moves in the left-right direction in FIG. 1 due to the balance between the pressure in the high-pressure chamber 44, the pressure in the low-pressure chamber 45, and the urging force of the return spring 46, the piston pin 41 moves smoothly and the inner cam ring 2 moves.
4 can be rotated in the advance or retard direction.

Further, as shown in FIG. 1, the central axis C of the timer piston 42 and the central axis D of the spherical surface portion 41b of the piston pin 41 located parallel to the central axis C should not be positioned coaxially. By setting the position of the piston pin 41, it is possible to prevent the timer piston 42 from rotating in the circumferential direction, which tends to occur when the timer piston 42 moves in the left-right direction in FIG. 1. As a result, it is possible to prevent contact between the timer piston 42 and the timer piston 42 caused by the rotation of the timer piston 42 in the circumferential direction.

As shown in FIG. 2, the spill valve 50 is disposed at the tip of the spill passage 17, and has a valve body 51 and a valve body 5.
3 and a compression coil spring 52 for urging the valve element 53 in the opening direction, an exciting portion 54 including an exciting coil, and the like. The spill valve 50 controls the injection amount by connecting or blocking the spill passage 17 and the intake gallery 14 during the fuel distribution stroke to overflow the pressurized fuel. When the exciting current is supplied to the exciting unit 54, the valve body 53 is attracted in the valve closing direction against the urging force of the compression coil spring 52 to close the valve.

When the distribution passage 16 of the cylinder 6 communicates with the distribution port 26 of the distribution rotor 13 as the distribution rotor 13 rotates, the communication passage 25, the discharge passage 27, the annular groove 29, the distribution port 26, the distribution passage 16 and the fuel passage 18 are formed. The plunger chamber 21 communicates with the delivery valve 19 via the. Then, the high-pressure fuel in the plunger chamber 21 is sent to the delivery valve 19 via the above-mentioned passages, and the high-pressure fuel is injected from the nozzle attached to the tip of the injection pipe (not shown) connected to the delivery valve 19. .

When the exciting current is not supplied to the exciting portion 54, the valve body 53 is biased in the valve opening direction by the biasing force of the compression coil spring 52 to open the valve. Then, since the annular groove 29 communicates with the low pressure side through the spill passage 17, the high pressure fuel in the plunger chamber 21 flows into the low pressure side through the discharge passage 27 and the annular groove 29 as described above. As a result, the high-pressure fuel that has been supplied to the nozzle (not shown) via the delivery valve 19 is cut off, and fuel injection from the nozzle ends. Further, at this time, since the spill valve 50 is opened, the intake gallery 14 and the spill passage 17 communicate with each other via the return passage 31, so that a part of the high pressure fuel overflowing to the low pressure side enters the intake gallery 14. It is possible to reflow and inhale.

Next, one cycle of the fuel injection process from the end of fuel injection of the injection pump 10 to the end of the next fuel injection will be described with reference to FIG. (1) The distribution rotor 13 rotates with the rotation of the drive shaft 1, and the cam crests of the inner cam ring 24 and the rollers 23 engage with each other. Then, each plunger 20 moves inward of the distribution rotor 13 in the radial direction, and the volume of the plunger chamber 21 decreases, so that the pressure of the plunger chamber 21 increases.
Then, the intake port (not shown) communicating with the fuel passage 25 and the intake passage 15 are cut off, the distribution port 26 of the distribution rotor 13 communicates with the distribution passage 16, and the fuel pressurized in the plunger chamber 21 has a certain pressure or more. Then, high-pressure fuel is supplied from the delivery valve 19 to the nozzle (not shown) via the distribution port 26, the distribution passage 16, and the fuel passage 18, and the fuel is injected into the cylinder of the engine (not shown).

(2) When the cam lobes of the inner cam ring 24 and the rollers 23 are not engaged, each plunger 2
When 0 moves to the outside of the distribution rotor 13 in the radial direction, the volume of the plunger chamber 21 increases, so that the pressure in the plunger chamber 21 decreases. Here, when the suction port 25 of the distribution rotor 13 communicates with any of the suction passages 15, the fuel filled in the suction gallery 14 in preparation for the next injection is sucked into the plunger chamber 21.

Next, the procedure for assembling the timer section 40 will be described with reference to FIG. First, the timer piston 42 having the return spring 46 assembled therein is housed in the liner 43 assembled in the timer chamber 3a of the pump housing 3.
At this time, the timer piston 42 is positioned so that the side on which the return spring 46 is assembled is located in the low pressure chamber 44 direction and the opening of the hole 42a is located in the inner cam ring 24 direction.

After accommodating the timer piston 42 in the liner 43, a slide plate 48 is provided around the spherical surface portion 41b.
While positioning a and b, from the piston pin insertion hole 3b of the pump housing 3 to the hole 42a of the timer piston 42.
The piston pin 41 is inserted therein. At this time, the slide plates 48a and 48b are housed in the holes 42a so that the slide plate 48a is located on the high pressure chamber 45 side and the slide plate 48b is located on the low pressure chamber 44 side.

Piston pin 41 inserted in hole 42a
By applying a tool such as a wrench inserted from the piston pin insertion hole 3b to the nut portion 41a of the same, and rotating the tool such as a wrench in a predetermined direction, the female screw portion 24b of the inner cam ring 24 and the male screw portion 41d of the piston pin 41 that are screwed together. And are tightened. Then, by rotating the nut portion 41a in a predetermined direction until the predetermined torque is reached, the female screw portion 24b is formed.
The screw fastening between the male screw portion 41d and the male screw portion 41d is completed, and the assembling of the piston pin 41 to the inner cam ring 24 is completed.

The inner cam ring 24 has a piston pin 4
After assembling 1, the lid 47 is assembled by screw fastening to the opening of the timer chamber 3a, and the piston pin insertion hole 3b
By assembling the blind plug 49 into the opening of the
The assembling of the timer unit 40 is completed. In the present embodiment, the piston pin 41 located inside the timer piston 42 is
Although the spherical portion 41b having a spherical shape is formed in a part of the above, the present invention is not limited to this, and for example, a cylindrical portion having a cylindrical shape may be formed in a part of the piston pin located in the timer piston. good. In this case, the inner wall surface of the slide plate located around the cylindrical portion is formed into a concave curved surface capable of making surface contact with the outer wall surface of the cylindrical portion, and the outer peripheral wall of the slide plate is hemispherical, that is, two slide plates are assembled. It is necessary to form a shape that becomes spherical when combined, and it is necessary to form the inner wall of the hole of the piston pin that contacts the outer peripheral wall of the slide plate into a concave spherical surface that can make surface contact with the hemispherical outer peripheral wall of the slide plate. There is. As a result, the contact between the cylindrical portion of the piston pin and the slide plate is made into surface contact, and the contact between the slide plate and piston pin is also made into surface contact, so that the pressure applied to each contact portion can be reduced. The same effect as can be obtained.

Further, although the two slide plates 48a and 48b are used in the present embodiment, the present invention is not limited to this, and for example, three or more slide plates may be used. In this case, it is necessary to arrange each slide plate so that the end portion of the slide plate is not located on the line of action of the timer piston. This is to prevent breakage of the slide plate due to excessive stress concentrated on the end of the slide plate located on the line of action of the timer piston. Also, a group of slide plates located on the high pressure chamber side of the central axis of the hole of the timer piston orthogonal to the central axis of the timer piston corresponds to the "first plate group" described in the claims, and the low pressure chamber A group of slide plates located on the side corresponds to the "second plate group" recited in the claims.

[Brief description of drawings]

1 is a partial cross-sectional view taken along line I-I of FIG. 2, showing a timer unit of a distributed fuel injection pump according to an embodiment of the present invention.

FIG. 2 is a sectional view of a distributed fuel injection pump according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing a positional relationship between a slide pin and a slide plate housed in a timer piston of a timer unit according to an embodiment.

FIG. 4 is a front view of a slide pin of a timer unit according to an embodiment.

FIG. 5 is a plan view of two slide plates of the timer unit according to the embodiment.

6 is a sectional view taken along line VI-VI shown in FIG.

FIG. 7 is a schematic cross-sectional view showing a positional relationship between a slide pin and a slide plate housed in a timer piston of a timer section according to a conventional example.

[Explanation of symbols]

10 injection pump 13 distribution rotor (distribution rotor) 20 plunger 24 inner cam ring (cam member) 40 timer part 41 piston pin 41 spherical surface part 42 timer piston (hydraulic piston) 42a hole part (through hole) 43 liner 44 high pressure chamber (high pressure side) ) 45 low pressure chamber (low pressure side) 46 return spring 48a slide plate (plural plates,
First plate group) 48b Slide plate (plural plates,
Second plate group)

Claims (4)

[Claims] 1. A fuel injection timing control device for a distribution type fuel injection pump, which controls a fuel injection timing by adjusting a pressure feeding timing of a plunger that feeds fuel, and a cam member that adjusts a pressure feeding timing of the plunger. A hydraulic piston that can reciprocate due to a change in pressure in the pressure control chamber, a piston pin that is inserted into the through hole of the hydraulic piston from the direction opposite to the cam member of the hydraulic piston and is attached to the cam member, and that is located in the through hole. A plurality of plates having an arc-shaped cross section provided between the outer peripheral wall of the piston pin and the inner peripheral wall of the through hole, and at least the line of action by which the reciprocating motion of the hydraulic piston is transmitted to the piston pin. One of the plurality of plates is located, and the inscribed circle and the circumscribed circle in the cross-sectional shape of the plurality of plates are eccentric. Fuel injection timing control device to. 2. The plurality of plates includes a first plate group located on the high pressure side of the pressure control chamber and a second plate group located on the low pressure side of the pressure control chamber, 2. The fuel injection according to claim 1, wherein a part of the plurality of plates forming the plate group has a larger thickness in a cross-sectional shape than the rest of the plurality of plates forming the second plate. Timing control device. 3. The first contact portion where the outer peripheral wall of the piston pin and the inner peripheral wall of the plurality of plates located inside the through hole contact each other is a surface contact or a line contact, and the plurality of plates. The outer peripheral wall of the hydraulic piston and the inner peripheral wall of the through hole of the hydraulic piston contact each other is a surface contact or line contact, at least one of the first contact portion and the second contact portion. The one of the two is contacted by a spherical surface.
Or the fuel injection timing control device described in 2. 4. The center of the spherical surface is eccentric with respect to the central axis of the hydraulic piston.
The fuel injection timing control device described.