JP4378190B2 - Plunger type fluid discharge device - Google Patents

Description

  The present invention relates to a plunger-type fluid discharge device capable of reducing operating noise.

  2. Description of the Related Art Conventionally, a plunger-type fluid discharge device that ejects or discharges fluid by reciprocating a plunger (movable element) including a valve body is known. Examples of the plunger type fluid discharge device include an electronically controlled fuel injection device and a plunger pump. The plunger-type fluid discharge device includes a stopper that the plunger collides with a moving end position of the plunger in the valve opening direction, and determines a movement restriction position of the plunger in the valve opening direction. However, each time the plunger is reciprocated, the plunger collides with the stopper, and a large collision sound is generated.

  Patent Document 1 discloses a plunger-type fluid discharge device that reduces the collision noise. The principal part of this patent document 1 is shown in FIG. A pipe 52 is fixed inside the housing 50, and a plunger 54 is provided inside the pipe 52 so as to be capable of reciprocating. A spring 56 for urging the plunger 54 in one direction is provided inside the pipe 52, and a coil 58 for operating the plunger 54 is provided outside the pipe 52. The plunger 54 reciprocates by turning on and off the current to the coil 58. An annular stopper (washer) 60 and a hollow cylindrical rubber (rubber) 62 are sandwiched between the pipe 52 and the housing 50 on the opposite side of the coil 58 in the plunger 54.

When the plunger 54 collides with the stopper 60 by the biasing force of the spring 56 during the reciprocating movement of the plunger 54, the plunger 54 moves together with the stopper 60 in the direction of pressing and compressing the rubber 62. Since the plunger 54 and the stopper 60 compress the rubber 62, the rubber 62 absorbs the collision sound when the plunger 54 collides with the stopper 60, and the collision sound can be reduced.
US Pat. No. 5,073,095 (FIG. 1)

  A contact surface 64 of the rubber 62 with the stopper 60 is an annular flat surface. The annular contact surface 64 is at a position perpendicular to the direction in which the plunger 54 and the stopper 60 compress the rubber 62. For this reason, the compressive force applied to the rubber 62 by the plunger 54 and the stopper 60 acts in a direction perpendicular to the contact surface 64. Since a compressive force is applied to the contact surface 64 of the rubber 62 in a direction perpendicular to the contact surface 64, the subsequent repulsive force immediately works toward the stopper 60 with the same force as the compressive force. The immediate repulsive force of the rubber 62 toward the stopper 60 is transmitted from the stopper 60 to the plunger 54, and the reciprocating movement of the plunger 54 becomes unstable. As a result, there is a possibility that an appropriate fuel flow rate cannot be discharged by the conventional technology.

  The present invention has been made in view of the above points, and provides a plunger type fluid discharge device that ensures a reduction in operating noise and stabilizes the reciprocating movement of the plunger so that an appropriate flow rate of fuel or the like can be discharged. It is intended to provide.

  To achieve the above object, the present invention includes a housing, a coil, a plunger that reciprocates in the housing, a spring that urges the plunger in a certain direction, and an opposite side of the spring in the plunger. A plunger-type fluid ejection device, comprising: a stopper that collides with the plunger; and an elastic body that contacts one of the stopper and the other directly or indirectly with the housing. A concave portion is formed on one side of the body and a convex portion is formed on the other side so as to be fitted and contacted with the concave portion, so that the opposing surfaces of the stopper and the elastic body other than the concave portion and the convex portion do not contact each other. It is a thing. In the present invention, the convex portion is formed on the stopper, and the concave portion is formed on the elastic body. In the present invention, the ratio C between the depth of the recess and the height of the elastic body is set to 1: 10 ≦ C <5:10. In the present invention, the convex portion is formed on the elastic body, and the concave portion is formed on the stopper. In the present invention, the cross section of the concave portion is formed from a central region and an outer region, the radius of curvature of the central region is made smaller than the radius of curvature of the outer region, and the convex portion is in a state where the plunger does not collide with the stopper. The protrusion is in contact with the central region and the outer region in a state where the portion contacts the central region and the plunger collides with the stopper. In the present invention, the ratio F between the depth of the recess and the height of the stopper is 1: 10 ≦ F ≦ 5: 10. In the present invention, the convex portion and the concave portion are annular.

  The elastic body and the stopper are fitted and brought into contact with the concave portion and the convex portion so that the surface of the elastic body facing the stopper and the surface of the stopper facing the elastic body are not in contact with each other even when the plunger collides with the stopper. . As a result, when the plunger collides with the stopper, the contact portion of the elastic body with the stopper slides laterally with respect to the collision direction, and the force is dispersed in the sliding movement direction. Also, since the opposing surface of the elastic body and the opposing surface of the stopper do not contact each other, the collision direction from the elastic body to the stopper at the time of the plunger collision compared to the conventional case where the opposing surface of the elastic body and the opposing surface of the stopper contact each other The repulsive force in the opposite direction becomes smaller. As a result, the reciprocating movement of the plunger can be stabilized and an appropriate flow rate of fuel or the like can be discharged.

Next, the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a plunger type fluid discharge device according to the present invention. The plunger type fluid discharge device includes a housing 10 (first housing 10A and second housing 10B) and a coil 12. A pipe 14 is provided inside the first housing 10 </ b> A, and a plunger 16 that can reciprocate is provided in the pipe 14. The plunger 16 is urged in a certain direction by a spring 18.

  A step portion 20 is formed in the first housing 10A. Between the step portion 20 of the first housing 10A and the pipe 14, an annular (or cylindrical) collar 22 and an elastic body 24 made of rubber or the like are used. And the stopper 26 are clamped. Although the collar 22, the elastic body 24, and the stopper 26 are annular (or cylindrical), they are not necessarily limited to an annular or cylindrical shape.

  2 and 3 are enlarged cross-sectional views of the main parts of the pipe 14, the collar 22, the elastic body 24, the stopper 26, and the plunger 16. FIG. 2 shows a state where the plunger 16 is separated from the stopper 26, and FIG. 3 shows a state where the plunger 16 collides with the stopper 26. The pipe 14 and the collar 22 are set at positions that do not move relative to the first housing 10A (FIG. 1). An annular concave portion 30 is formed on the opposing surface 28 of the elastic body 24 facing the stopper 26, and an annular convex portion 34 is formed on the opposing surface 32 of the stopper 26 facing the elastic body 24. 30 and the convex portion 34 of the stopper 26 are set so as to be in contact with each other. The concave portions 30 formed in the elastic body 24 are not in an annular shape, but are in a number of partial spherical shapes, and the convex portions 34 formed in the stopper 26 are also not in an annular shape but in a number of partial spherical shapes. In addition, all of the partial spherical concave portions 30 and the convex portions 34 may be fitted.

  In the state of FIG. 2 where the plunger 16 does not collide with the stopper 26, the concave portion 30 and the convex portion 34 are fitted and contacted, but the opposing surface 28 of the elastic body 24 and the opposing surface 32 of the stopper 26 are not contacted. To do. 2, the thickness of the elastic body 24 is H, the depth of the concave portion 30 of the elastic body 24 is h1, the contact width between the concave portion 30 and the convex portion 34 is B1, and the opposing surface 28 of the elastic body 24 is And a gap interval between the opposing surface 32 of the stopper 26 and L1. Here, when the ratio of h1: H is C, it is desirable that 1: 10 ≦ C <5:10. When the ratio C of h1: H is 1:10 or less, the contact area between the concave portion 30 and the convex portion 34 becomes small, and the opposing surface 28 of the elastic body 24 and the opposing surface of the stopper 26 when the plunger 16 collides with the stopper 26. 32 may come into contact. Further, when the ratio C of h1: H is 5:10 or more, stress concentration is applied to the concave portion 30 of the elastic body 24, and the concave portion 30 may be cracked.

  2, when the plunger 16 collides with the stopper 26, the plunger 16 moves to the elastic body 24 side together with the stopper 26, and the convex portion 34 of the stopper 26 pushes the concave portion 30 of the elastic body 24 (FIG. 3). In the state of FIG. 3, the dimension of the thickness H of the elastic body 24 does not change, the depth h2 of the concave portion 30 of the elastic body 24 is deeper than h1 in FIG. 2, and the contact width B2 between the concave portion 30 and the convex portion 34. Is larger than B1, and the gap interval L2 between the opposed surface 28 of the elastic body 24 and the opposed surface 32 of the stopper 26 is smaller than L1. However, even in the state of FIG. 3, the setting is made so that the facing surface 28 of the elastic body 24 and the facing surface 32 of the stopper 26 are not in direct contact. In the present invention, the operating sound can be reduced by the elastic body 24 as in the prior art.

  In the state where the plunger 16 shown in FIG. 3 collides with the stopper 26, the convex portion 34 of the stopper 26 presses and compresses the concave portion 30 of the elastic body 24, but the portion compressed and compressed by the elastic body 24 is near the concave portion 30. The pushing direction is the left and right direction (arrow X direction) along the convex portion 34 of the plunger 16, and the portion near the concave portion 30 of the elastic body 24 slides in the X direction. As described above, in the present invention, the impact force of the plunger 16 on the elastic body 24 can be dispersed in the X direction different from the collision direction, and the force that immediately repels from the elastic body 24 to the plunger 16 can be reduced. As a result, the reciprocating movement of the plunger 16 can be stabilized, and an appropriate flow rate of fuel or the like can be discharged. The repulsive force from the elastic body 24 to the plunger 16 can be reduced by making the diameter of the elastic body 24 shorter than the diameter of the stopper 26 so that the outer peripheral wall 35 of the elastic body 24 does not contact the housing 10. .

  In FIG. 2, the entire area of the concave portion 30 of the elastic body 24 is in contact with the convex portion 34 of the stopper 26. However, as shown in FIG. 4, the concave portion 30 is rounded at the deepest portion. The deepest portion may have a V shape that does not contact the convex portion 34.

  2 and 3, the elastic body 24 is formed with the concave portion 30 and the stopper 26 is formed with the convex portion 34. On the contrary, the elastic body 24 is formed with the convex portion and the stopper 26 is formed with the concave portion. What is to be done is shown in FIGS. FIG. 5 shows a state where the plunger 16 is separated from the stopper 26, and FIG. 6 shows a state where the plunger 16 collides with the stopper 26. As shown in FIG. 5, an annular convex portion 38 is formed on the facing surface 36 of the elastic body 24 facing the stopper 26, and an annular concave portion 42 is formed on the facing surface 40 of the stopper 26 facing the elastic body 24. . The cross section of the recess 42 includes a central region 44 (a region between P1 and P2) and an outer region 46 (a region between P1 and Q1 and a region between P2 and Q2). It is assumed that the radius of curvature of the central region 44 is smaller than the radius of curvature of the outer region 46.

  In the state of FIG. 5 in which the plunger 16 is separated from the stopper 26, the convex portion 38 of the elastic body 24 contacts the central region 44 of the concave portion 42 of the stopper 26, but does not contact the outer region 46 of the concave portion 42. Is set. Further, the opposing surface 28 of the elastic body 24 and the opposing surface 32 of the stopper 26 are set so as not to contact each other.

  When the plunger 16 collides with the stopper 26 from the state of FIG. 5, the stopper 26 moves toward the elastic body 24 and pushes the convex portion 38 of the elastic body 24. As a result, not only the central region 44 but also the outer region 46 of the concave portion 42 of the stopper 26 contacts the convex portion 38 of the elastic body 24 (FIG. 6). Even in the state of FIG. 6, the opposing surface 28 of the elastic body 24 and the opposing surface 32 of the stopper 26 are set so as not to contact each other.

  In a state where the concave portion 42 (both the central region 44 and the outer region 46) of the stopper 26 is in contact with the convex portion 38 of the elastic body 24, the convex portion 38 of the elastic body 24 is pushed by the concave portion 42 of the stopper 26 and deforms. The pressing direction of the convex portion 38 of the elastic body 24 is a direction along the outer region 46 of the concave portion 42 of the stopper 26 (the arrow Y direction), and a part of the elastic body 24 slides in the Y direction. By applying a force in the Y direction to the elastic body 24, the collision force of the plunger 16 against the elastic body 24 can be dispersed in the Y direction, and the force that immediately repels from the elastic body 24 to the plunger 16 can be reduced. As a result, it is possible to ensure a reduction in operating noise, stabilize the reciprocating movement of the plunger 16, and discharge an appropriate flow rate of fuel or the like.

  Here, if the ratio of the depth D of the recess 42 (center region 44) of the stopper 26 to the height E of the stopper 26 is F, it is desirable that 1: 10 ≦ F ≦ 5: 10. When F is 1:10 or less, the contact area between the concave portion 30 and the convex portion 34 becomes small, and the opposing surface 28 of the elastic body 24 and the opposing surface 32 of the stopper 26 come into contact when the plunger 16 collides with the stopper 26. There is a fear. Further, if F is 5:10 or more, stress concentration is applied to the concave portion 42 of the stopper 26 and the concave portion 42 may be cracked.

  Although the outer region 46 is on both sides of the central region 44, only one of them may be provided. Even when the convex portion 38 is formed on the elastic body 24, the repulsive force from the elastic body 24 to the plunger 16 is reduced by preventing the outer peripheral wall 35 of the elastic body 24 from contacting the housing 10.

It is sectional drawing of the plunger type fluid discharge apparatus which concerns on this invention. It is a principal part expanded sectional view which shows the state which the plunger has left | separated from the stopper. It is sectional drawing which shows the state which the plunger collided with the stopper from the state of FIG. It is sectional drawing which shows the modification of FIG. It is a principal part expanded sectional view of the other structure which shows the state which the plunger has left | separated from the stopper. It is sectional drawing which shows the state which the plunger collided with the stopper from the state of FIG. It is sectional drawing of the conventional plunger type fluid discharge apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Housing 12 Coil 16 Plunger 18 Spring 24 Elastic body 26 Stopper 28 Opposing surface 30 Concave portion 32 Opposing surface 34 Convex portion 36 Opposing surface 38 Convex portion 40 Opposing surface 42 Concave portion 44 Central region 46 Outer region

Claims (7)

  A housing, a coil, a plunger that reciprocates in the housing, a spring that urges the plunger in a certain direction, and a stopper that is provided on the opposite side of the spring in the plunger and that the plunger collides with. In the plunger-type fluid ejection device having one of the stoppers and one of the elastic members in direct or indirect contact with the housing, a concave portion is formed in one of the stopper and the elastic body and the other The plunger-type fluid discharge device is characterized in that a convex portion that fits and contacts the concave portion is formed so that the opposing surfaces of the stopper and the elastic body other than the concave portion and the convex portion do not contact each other. .   The plunger-type fluid ejection device according to claim 1, wherein the convex portion is formed on the stopper and the concave portion is formed on the elastic body.   The plunger-type fluid ejection device according to claim 2, wherein a ratio C between the depth of the recess and the height of the elastic body is set to 1: 10≤C <5:10.   The plunger-type fluid ejection device according to claim 1, wherein the convex portion is formed on the elastic body, and the concave portion is formed on the stopper.   The cross section of the concave portion is formed from a central region and an outer region, the radius of curvature of the central region is smaller than the radius of curvature of the outer region, and the convex portion is in the middle when the plunger does not collide with the stopper. The plunger-type fluid ejection device according to claim 4, wherein the convex portion is in contact with the central region and the outer region in a state where the convex portion is in contact with the region and the plunger collides with the stopper.   6. The plunger type fluid discharge device according to claim 5, wherein a ratio F of the depth of the concave portion and the height of the stopper is 1: 10 ≦ F ≦ 5: 10.   The plunger-type fluid ejection device according to claim 1, wherein the convex portion and the concave portion are annular.

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