JP2016061196A - High pressure fuel supply pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relief valve structure which stably exerts high fuel release properties, and a high pressure fuel supply pump mounting the same, with a small and low-cost configuration.SOLUTION: In a body of a high pressure fuel supply pump, a suction passage, a pressurizing chamber, and a discharge passage are formed sequentially from an upstream side, a solenoid-valve for determining a fuel amount is arranged in the suction passage, a discharge valve for limiting a circulation direction of the fuel is arranged in the discharge passage, and a relief valve is provided in a relief passage formed between the upstream and the downstream of the discharge valve. In the relief valve, a seat part is formed for sealing the fuel by a valve body and a valve seat part provided in the relief passage coming into contact, and other than the seat part, a fluid passage is provided for including a part of the valve body and for forming a fluid throttle. The relief valve also includes a cylindrical wall part formed in the relief passage, and a guide part for sliding in the wall part and formed integrally with the valve body, and eccentricity of the valve body in a radial direction is suppressed by the guide part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-pressure fuel supply pump that supplies fuel to an internal combustion engine at a high pressure, and more particularly, to a high-pressure fuel supply pump having a relief valve structure that stably exhibits high fuel release characteristics.

  Recently, vigorous progress has been made in reducing the size, efficiency, and exhaust of internal combustion engines. In response, high-pressure fuel supply pumps are strongly demanded to reduce the size of the body to improve its mountability to internal combustion engines, and to increase the pressure and volumetric efficiency of the discharged fuel in response to high efficiency and low exhaust. Yes.

  One of the most important issues for the higher pressure of the high-pressure fuel supply pump, which is a requirement of these, is the development of a relief valve inside the high-pressure fuel supply pump. Since the relief valve determines the maximum allowable pressure of the entire fuel supply system, there is a severe demand for improvement of the fuel release characteristics. For this reason, development of a relief valve that stably exhibits high opening performance is required.

  In this regard, various proposals have conventionally been made regarding the structure of relief valves. Among them, for example, Patent Document 1 discloses a structure in which a fluid throttle is provided on a side surface of a relief valve to form an intermediate chamber, and a valve body lift is increased by pressure stored therein. Patent Document 2 discloses a structure that stabilizes the behavior of a relief valve of a hydraulic continuously variable transmission by guiding a valve body.

Patent 5103138 JP 2003-301955 A

  As an example of improving the opening characteristics of the relief valve, in the example of Patent Document 1, the pressure loss generated in the fluid throttle provided on the side surface of the relief valve causes pressure accumulation in an intermediate chamber formed between the seat portion and the fluid throttle, This is configured to act on the bottom surface of the valve body. Thereby, the fluid force in the valve opening direction acts on the valve body, the lift is increased, and high opening performance can be obtained.

  However, with this structure, the valve body may be eccentric in the radial direction. When the valve body is eccentric, the shape of the annular gap provided on the side surface changes. As a result, there is a possibility that the differential pressure generated between the front and the rear theoretically decreases to 1 / 2.5 times that when there is no eccentricity. For this reason, the pressure in the intermediate chamber is greatly affected by the eccentricity of the valve body, and the lift and release characteristics vary.

  The influence of the eccentricity described above is a new problem that becomes more prominent by providing a fluid throttle on the side surface of the valve body. In order to solve this, it is necessary to increase the dimensional accuracy of the gap width so as to be within the allowable value even if the aforementioned variation in open characteristics occurs, which is not preferable from the viewpoint of cost reduction.

  Patent Document 2 discloses a structure that guides a valve body and stabilizes its behavior. However, in this structure, a fluid throttle is not formed on the side surface of the valve body, and high opening characteristics cannot be expected. In addition, it is assumed that the relief valve is built in the discharge valve, and the guide portion is not fixed to the pump body. For this reason, there is a possibility that the valve body behavior cannot be sufficiently stabilized due to the movement of the guide portion itself.

  In view of the above, an object of the present invention is to provide a relief valve structure that stably exhibits high fuel release characteristics and a high-pressure fuel supply pump equipped with the relief valve structure with a small and inexpensive structure.

From the above, in the present invention, the suction passage, the pressurizing chamber, and the discharge passage are formed in the body from the upstream side in this order, and the intake passage determines the fuel amount in the suction passage. A relief valve is disposed, and a relief valve is provided in a relief passage formed between the upstream and downstream of the discharge valve, and the relief valve is in contact with a valve body provided in the relief passage and a valve seat portion. A high pressure fuel supply pump in which a seat portion for sealing fuel is formed and a fluid passage including a part of a valve body and forming a fluid throttle is provided in addition to the seat portion,
The relief valve further includes a cylindrical wall portion formed in the relief passage, and a guide portion that slides in the wall portion and is formed integrally with the valve body, and is eccentric in the radial direction of the valve body by the guide portion. Suppress.

  In the embodiment of the present invention, the following configuration is further preferable. The guide portion is disposed inside a return spring that urges the valve body to the valve seat portion, and a fluid throttle is formed by a gap formed between the housing housing the relief valve component and the valve body, The sheet part and the guide part are integrally formed.

  Further, when the valve body moves in the valve opening direction, a stopper is provided so as to restrict the movement of the valve body before the lines of the return springs are in close contact with each other. The stopper may be formed of a member that receives the urging force of the return spring, may be formed directly on the pump body, or may be formed of another member that has been subjected to heat treatment or surface treatment.

  The fluid throttle may be formed by an annular gap formed on the side surface of the valve body or a through hole penetrating the valve body. Furthermore, when assembling, after inserting a valve body in a housing, a return spring may be fitted, it may unitize by fixing with a stator, and the method fixed to a pump body after that may be taken.

  According to the configuration of the present invention, a relief valve structure that stably exhibits high fuel release characteristics and a high-pressure fuel supply pump equipped with the relief valve structure can be realized with a small and inexpensive structure.

The figure which shows the cross section of the relief valve 30 which concerns on Example 1 of this invention. The figure which shows the whole high-pressure fuel supply pump system structure with which the Example of this invention is applied. The figure which shows the cross section of the relief valve 30 which concerns on the deformation | transformation of Example 1 of this invention. The figure which shows the relief valve structure described in patent document 1. FIG. The figure which shows the cross section of the relief valve 30 which concerns on Example 2 of this invention. The figure which shows the cross section of the relief valve 30 which concerns on Example 3 of this invention. The figure which shows the cross section of the relief valve 30 which concerns on the deformation | transformation of Example 3 of this invention. The figure which shows the stopper structure of FIG. The figure which shows the cross section of the relief valve 30 which concerns on other deformation | transformation of Example 3 of this invention. The figure which shows the cross section of the relief valve 30 which concerns on Example 4 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Example 1 will be described with reference to FIGS. 1, 2, and 3. Of these, FIG. 2 shows the overall configuration of a high-pressure fuel supply pump system to which the embodiments of the present invention (Embodiments 1 to 4) are applied. For this reason, the overall configuration will be described first with reference to FIG. 2, and then each embodiment of the relief valve structure will be described.

  The high-pressure fuel supply pump system shown in FIG. 2 is roughly divided into a fuel tank fuel tank 101 on the left side in the figure, a high-pressure fuel supply pump 300 in the center in the figure, a fuel injection system 200 on the right side in the figure (common rail 53, injector 54, etc.), engine A control unit (ECU) 40 and an internal combustion engine 400 in the lower center of the figure (lower side of the high-pressure fuel supply pump 1) are configured.

  The high-pressure fuel supply pump 300 incorporates a plurality of components and mechanisms in the body 1 and is attached to the cylinder head 20 of the internal combustion engine 400. In the body 1, a suction passage 9, a pressurizing chamber 11, a discharge passage 12, and a relief passage 15 are formed. The suction passage 9 is provided with an electromagnetic valve 5, the discharge passage 12 is provided with a discharge valve 8, and the relief passage 15 is provided with a relief valve 30. The pressurizing chamber 11 in the body 1 is changed in volume by the plunger 2 that moves up and down by the rotation of the cam 7 of the internal combustion engine, so that the pump operation is possible. The functions of the respective valves formed in the high-pressure fuel supply pump 300 will be briefly described. The electromagnetic valve 5 is an adjustment valve that determines the amount of fuel to be pressurized, and the discharge valve 8 changes the fuel flow direction. The relief valve 30 serves as a safety valve that opens the common rail 53 when the pressure in the common rail 53 exceeds a predetermined pressure.

  In general, according to the high-pressure fuel supply pump system configured as described above, fuel from the fuel tank 101 is guided into the high-pressure fuel supply pump 300, and the solenoid valve 5 in the suction passage 9, the pressurizing chamber 11, and the discharge valve 8 in the discharge passage 12. The pressure is increased by passing through and is supplied to the fuel injection system 200. The high-pressure fuel supply pump is connected to the common rail 53 of the fuel injection system 200, the pressurized fuel is pumped, and the high-pressure fuel is injected from the injector 54 into the combustion chamber of the internal combustion engine. The pressure in the common rail 53 is measured by the pressure sensor 56, and the signal is sent to the engine control unit (ECU) 40. The injectors 54 are mounted in accordance with the number of cylinders of the engine, and inject fuel with a signal from an engine control unit (ECU) 40. The engine control unit (ECU) 40 controls the electromagnetic valve 5 in the high pressure fuel supply pump.

  The high-pressure fuel supply pump system in FIG. 2 is configured as described above. The present invention relates to the improvement of the relief valve 30, but before that, each function of the high-pressure fuel supply pump will be described in more detail.

  First, the connection relationship with the internal combustion engine for causing the pressurizing chamber 11 to perform the pump operation will be described. The plunger 2 below the pressurizing chamber 11 is slidably inserted into the cylinder 120, and the retainer 3 is attached to the lower end. The urging force of the plunger return spring 4 acts on the retainer 3 in the downward direction in FIG. The tappet 6 reciprocates in the vertical direction in FIG. 2 by the rotation of the cam 7 of the internal combustion engine. Since the plunger 2 is displaced following the tappet 6, this changes the volume of the pressurizing chamber 11 and enables the pump operation.

  Next, the configuration of the electromagnetic valve 5 in the high-pressure fuel supply pump controlled by a signal from the engine control unit (ECU) 40 will be described. The electromagnetic valve 5 is held by the body 1, and an electromagnetic coil 500, a mover 503, an anchor spring 502, and a valve body spring 504 are arranged. Hereinafter, the description will be made on the assumption that the movable portion 503 is formed of one member. However, the movable portion 503 may be formed of two members including an anchor that forms a magnetic attraction surface and a rod that forms a sliding portion. Good.

  In the following, the description will proceed on the premise of a system using a normally open solenoid valve. An electromagnetic valve system in which the electromagnetic coil 500 is opened when the electromagnetic coil 500 is OFF and closed when the electromagnetic coil 500 is ON is referred to as a normal open system. The urging force of the anchor spring 502 acts on the valve body 501 in the valve opening direction via the movable portion 503, and similarly, the urging force of the valve body spring 504 acts on the valve body 501 in the valve closing direction. Here, since the urging force of the anchor spring 502 is larger than the urging force of the valve body spring 504, the valve body 501 is in the valve open state when the electromagnetic coil 500 is OFF (non-energized). The operation is reversed, that is, even if a system using an electromagnetic valve system called a normally closed system in which the valve body 501 is closed when the electromagnetic coil 500 is OFF (no power supply) is the same. It is possible to implement Example 1 to Example 4.

  Finally, the relief valve 30 that is the subject of the present invention will be described. The relief valve 30 is formed by a valve body 151 and a valve seat 157. In the following description, the description will be made on the premise of a system using the pressurized chamber return method. Here, a method of opening the abnormal high pressure generated on the common rail 53 side to the pressurizing chamber 11 is referred to as a pressurizing chamber returning method.

  The relief valve 30 in FIG. 2 is formed in the relief passage 15, and the relief passage 15 is connected to the downstream side (fuel injection system 200 side) of the discharge valve 8 and the pressurizing chamber 11. A valve body 151 is arranged in a direction to open from the downstream side to the pressurizing chamber 11 side. The valve body 151 is biased to the valve seat portion 157 by a return spring 154, and a seat portion 150 that seals fuel is formed at a contact portion between the two. The behavior of the valve body 151 is governed by the differential pressure generated before and after the seat portion 150. When the differential pressure generated thereby overcomes the urging force of the return spring 154, the valve opening operation is started. Note that the first to fourth embodiments can be similarly implemented on the premise of a system using a low pressure return system in which the relief passage 15 is connected to the downstream side of the discharge valve 8 and the damper chamber 51. .

  Next, a detailed pump operation and flow rate control method realized in the above configuration will be described. First, the state in which the plunger 2 is displaced downward in FIG. 2 due to the rotation of the cam 7 of the internal combustion engine is referred to as a suction process, and the state in which the plunger 2 is displaced upward is referred to as a compression process. In the suction process, the volume of the pressurizing chamber 11 increases and the fuel pressure therein decreases. In this step, when the fuel pressure in the pressurizing chamber 11 becomes lower than the fuel pressure in the suction passage 9, the valve body 501 of the electromagnetic valve 5 is opened and the fuel is sucked into the pressurizing chamber 11.

  At this time, since the urging force of the anchor spring 502 acts on the valve body 501 via the movable portion 503, the valve body 501 of the electromagnetic valve 5 still remains even if the plunger 2 shifts from the suction process to the compression process. Keep the valve open. Accordingly, even during the compression process, the pressure in the pressurizing chamber 11 is maintained at a low pressure almost equal to that of the suction passage 9, so that the discharge valve 8 cannot be opened, and the fuel corresponding to the volume reduction in the pressurizing chamber 11 is achieved. Passes through the electromagnetic valve 5 and is returned to the damper chamber 51 side. This process is called a return process.

  When the electromagnetic coil 500 of the electromagnetic valve 5 is energized in the returning step, a magnetic attractive force acts on the movable element 503, overcomes the urging force of the anchor spring 502, and the movable portion 503 of the electromagnetic valve 5 moves in the valve closing direction. Then, the valve body 501 is closed by the biasing force of the valve body spring 504 and the fluid differential pressure of the return fuel. When the valve body 501 is closed, the fuel pressure in the pressurizing chamber 11 increases with the rise of the plunger 2 immediately after this. As a result, the discharge valve 8 is automatically opened, and the fuel is pumped to the common rail 53.

  If the electromagnetic valve 5 that operates as described above is used, the flow rate that the pump discharges can be controlled by adjusting the timing at which the electromagnetic coil 500 is turned on.

  FIG. 1 shows a cross-sectional view of a relief valve 30 according to Embodiment 1 of the present invention. In FIG. 1, 1 is a body of a high-pressure fuel supply pump, 150 is a seat, 151a is a ball valve, 151b is a valve body holder, 153a is a through hole, 154 is a return spring, 155a is a stator, 156 is a housing, 157 is The valve seat portion, 158 is a guide portion, 160 is an intermediate chamber, and 161 is a pressure receiving area. The ball valve 151a and the valve body holder 151b together constitute a valve body 151. Both can be formed as one member, but the processing cost can be reduced by using a ball-shaped commercial material for the portion where the sheet portion 150 is formed.

  The ball valve 151a is urged by a return spring 154 in the direction of the valve seat portion 157 via the valve element holder 151b, and a seat portion 150 for sealing fuel is formed at the contact portion between the two. The behavior of the valve body 151 is governed by the differential pressure generated before and after the seat portion 150. When the differential pressure generated by the difference between the upstream side (right side of the drawing) pressure and the downstream (left side of the drawing) pressure exceeds the urging force of the return spring 154, the valve body 151 opens to the left side of the drawing. To start. At this time, by adjusting the press-fitting depth of the stator 155a fixed to the housing 156 by press-fitting, it is possible to adjust the biasing force of the return spring 154 and change the differential pressure at which the valve opening operation starts. is there.

  When the valve body 151 is opened, the fuel passes through the seat portion 150 and reaches the intermediate chamber 160, and is released through a through hole 153a provided as a fluid passage in a part of the valve body 151. Providing the through hole 153a in a part of the valve body 151 is advantageous from the viewpoint of space saving compared to the case of providing a new fluid passage separately from the valve body 151. In addition, the through hole 153a forms a fluid throttle that generates a pressure loss with respect to the flow, whereby pressure is stored in the intermediate chamber 160. With such a configuration, the pressure stored in the intermediate chamber 160 acts on the pressure receiving surface 161 formed on the end surface of the valve body holder 151b, and the valve opening lift of the valve body 151 can be increased. As a result, a high opening characteristic can be obtained with a small and simple relief valve structure. Furthermore, a guide portion 158 that suppresses eccentricity in the radial direction is provided on a side surface of the valve body holder 151b. Thereby, the behavior of the valve body 151 is stabilized, and a more stable opening characteristic can be obtained. The valve body 151 stops at a position determined by the gap between the spring lines of the compressed return spring 154.

  Also, at the time of assembly, each part is assembled to the housing 156 and fixed by the stator 155a, and once unitized, the housing 156 is press-fitted into the pump body 1, thereby improving the assembly performance and reducing the assembly cost. Can be reduced. Below, the assembly | attachment procedure of each component is demonstrated. First, the ball valve 151 a and the valve body holder 151 b are inserted into the housing 156. Thereafter, the return spring 154 is inserted, and the stator 155a is press-fitted and fixed to form a unit.

  FIG. 3 shows a modification of the first embodiment. Here, the housing 156 is not used, and the components are directly assembled to the pump body 1. By doing so, it is possible to make the structure cheaper. At the time of assembly, first, the return spring 154 is inserted into the pump body 1, and then the valve body holder 151b and the ball valve 151a are inserted. Finally, the valve seat 157 is fixed by press fitting. Further, it is possible to adjust the biasing force of the return spring 154 by adjusting the press-fitting depth.

  FIG. 4 is a view showing the relief valve structure described in Patent Document 1 described above. Due to the pressure loss generated by the fluid throttle provided on the side surface of the relief valve, pressure is accumulated in the intermediate chamber formed between the seat portion and the fluid throttle, and this is applied to the bottom surface of the valve body. As apparent from the comparison with FIG. 1, the difference is that a guide portion 158 that suppresses radial eccentricity is provided on the side surface of the valve element holder 151b. According to the configuration of FIG. 4 that does not include the guide portion 158, the valve body 151 is eccentric in the radial direction as shown in the lower part of FIG. 4, and when the valve body 151 is eccentric, the annular gap provided on the side surface As the shape changes, the pressure in the intermediate chamber is greatly influenced by the eccentricity of the valve body, and the lift and release characteristics vary.

  In the first embodiment, the guide body 158 in the relief passage 15 direction is formed integrally with the valve body 151, and the circumferential cross section of the guide section 158 has the same shape as the cross section of the relief passage 15, thereby decentering the valve body 151. It has been prevented.

  In the first embodiment, the guide portion 158 formed integrally in the relief passage 15 direction of the valve body 151 operates as an eccentricity prevention mechanism. Here, the relief passage 15 is a passage formed by the housing 156 in the body 1 in the case of FIG. 1, and is a passage directly formed by the body 1 in the case of FIG.

  According to the present invention of Example 1, the area variation of the fluid throttle can be reduced by the guide portion. The guide portion prevents the fluid throttle from tilting.

  As described above, the high-pressure fuel supply pump according to the first embodiment is configured such that the suction passage, the pressurization chamber, and the discharge passage are sequentially formed in the body from the upstream side, and the solenoid valve and the discharge passage determine the fuel amount in the suction passage. Is provided with a discharge valve for restricting the flow direction of the fuel, and a relief valve is provided in a relief passage formed between the upstream and downstream of the discharge valve. The relief valve is provided with a valve body and a valve provided in the relief passage. A high pressure fuel supply pump in which a seat portion for sealing fuel is formed by contact of a seat portion, and a fluid passage including a part of the valve body and forming a fluid throttle is provided in addition to the seat portion .

  In addition, it further includes a cylindrical wall portion formed in the relief passage, and a guide portion that slides in the wall portion and is formed integrally with the valve body. The guide portion deflects the valve body in the radial direction. The lead is suppressed.

  In the case of the embodiment of FIG. 1, the cylindrical wall portion formed in the relief passage is the housing 156, and the guide portion that slides in the wall portion and is formed integrally with the valve body is the guide portion 158. Correspond. In the case of the embodiment of FIG. 3, the cylindrical wall portion formed in the relief passage is the body 1, and the guide portion that slides in the wall portion and is formed integrally with the valve body is the guide portion 158. Corresponding to

  FIG. 5 shows a sectional view of a relief valve according to Embodiment 2 of the present invention. In FIG. 5, 1 is a pump body, 150 is a seat portion, 151a is a ball valve, 151b is a valve body holder, 152a is a vertical hole passage, 153b is an annular gap, 154 is a return spring, 155a is a stator, 156 is a housing, 157 , A valve seat portion, 158 a guide portion, 159 a stopper, 160 an intermediate chamber, and 161 a pressure receiving surface. The ball valve 151a and the valve body holder 151b together constitute a valve body 151. Both can be formed as one member, but the processing cost can be reduced by using a ball-shaped commercial material for the portion where the sheet portion 150 is formed.

  In this embodiment, the guide portion 158 as an eccentricity prevention mechanism is provided on the inner diameter side of the return spring 154. Specifically, the valve body 151 formed integrally with the guide portion 158 is disposed on the downstream side of the discharge valve of the relief passage 15, and the inner cylinder is formed on the valve body 151 side from the stator 155 a on the upstream side of the discharge valve of the relief passage 15. 201 is fixedly arranged. In addition, the guide portion 158 is fitted in the inner cylinder 201 and configured to be movable.

  By comprising in this way, the valve body holder 151b can be reduced in size and the annular clearance 153b can be formed in the side surface as a fluid passage. Then, by providing the annular gap 153b with the same fluid throttling effect as the through hole 153a described in the first embodiment, it is possible to obtain a high opening characteristic. In addition, since the fluid passage is formed by the annular gap 153b, it is not necessary to perform a highly accurate and expensive fine hole processing. For this reason, it is more advantageous from the viewpoint of cost reduction as compared with the case where the fluid passage is formed by the through hole 153a of FIGS. The fuel passes through the annular gap 153b and then passes through the vertical hole passage 152a provided in the stator 155a to be released.

  Further, a stopper 159 is provided at the end of the stator 155a. Even when the lift of the valve body 151 increases, the lift amount is limited to a predetermined value or less by contacting the stopper 159. Thereby, it can prevent that the line | wire of the return spring 154 closely_contact | adheres and an open characteristic falls. In addition, by forming the stator 155a that receives the biasing force of the return spring 154 and the stopper 159 from the same member, the maximum lift amount of the valve element 151 can be accurately determined with respect to the gap between the lines of the return spring 154. it can.

  Further, each area is set so that the cross-sectional area of the annular gap 153 b is smaller than the opening area of the seat portion 150 in the fully open state where the valve body 151 contacts the stopper 159. By doing so, a stable pressure can be stored in the intermediate chamber 160 even in the fully open state, and the valve open state can be maintained.

  In the case of FIG. 5, it can be said that eccentricity is prevented by sliding a guide portion 158 integrally formed with the valve body 151 in the relief passage 15. That is, the present invention includes a cylindrical wall portion formed in the relief passage, and a guide portion that slides in the wall portion and is formed integrally with the valve body, and is guided in the radial direction of the valve body by the guide portion. In the case of FIG. 5, the cylindrical wall part formed in the relief passage is a hollow inner cylinder 201, and slides in the wall part so as to be integrated with the valve body. The formed guide part corresponds to the guide part 158.

  With the configuration as described above, a relief valve that stably exhibits high opening characteristics can be realized with a small and inexpensive structure.

  FIG. 6 shows a cross-sectional view of a relief valve according to Embodiment 3 of the present invention. In FIG. 6, 1 is a pump body, 150 is a seat part, 152b is a vertical hole passage, 153b is an annular gap, 154 is a return spring, 155b is a stator, 156 is a housing, 157 is a valve seat part, 158 is a guide part, Reference numeral 159 denotes a stopper, 160 denotes an intermediate chamber, 161 denotes a pressure receiving surface, and 162 denotes a slit.

  In the third embodiment, the return spring 154 that is disposed closer to the pressurizing chamber 11 than the seat portion 150 in the first and second embodiments is disposed on the downstream side of the discharge valve 8 that is opposite to the return spring 154. Further, the guide portion 158 as an eccentricity prevention mechanism is provided on the inner diameter side of the return spring 154. Specifically, the valve body 151 formed integrally with the guide portion 158 is disposed on the upstream side of the discharge valve of the relief passage 15, and the stator 155b for fixing the return spring 154 is disposed on the downstream side of the discharge valve of the relief passage 15. To do. Further, a housing 156 (corresponding to the inner cylinder 201 in FIG. 5) is fixedly arranged from the upstream side of the discharge valve of the relief passage 15 to the downstream side of the discharge valve of the relief passage 15. In addition, a guide portion 158 is fitted in the housing 156 so as to be movable. The stator 155b is fixed to the downstream side of the discharge valve of the guide portion 158. As a result, the urging force by the return spring 154 acts on the valve body 151.

  By comprising in this way, the return spring 154 is excluded from the inside of the pressurizing chamber 11, and the space formed excessively around it can be excluded. This leads to a reduction in the useless volume in the pressurizing chamber 11 which is a main factor of a decrease in volumetric efficiency, and an improvement effect can be expected especially at high pressure where the tendency of volumetric efficiency to decrease is remarkable.

  In the structure of the third embodiment, when the valve body 151 is opened, the fuel flowing from the downstream side of the discharge valve 8 passes through the vertical hole passage 152b and is guided to the intermediate chamber 160 through the seat portion 150. The annular gap 153b serving as a fluid passage is formed by the side surface of the valve body 151 and the inner wall surface of the housing 156, and has a fluid throttle effect. Further, the housing 156 is integrally formed with a cylindrical wall portion that receives the seat portion 150 and the guide portion 158. As a result, the coaxiality of the seat part 150 and the guide part 158, which is important when ensuring oil tightness when the valve is closed, and the annular gap 153b and the guide part, which are important for maintaining a stable valve opening state. The concentricity can be managed at a lower cost and with higher accuracy than when each is formed of a separate member.

  Further, the pump body 1 is provided with a stopper 159 that restricts the lift of the valve body 151. By doing so, it is possible to prevent the return springs 154 from coming into close contact with each other with a simpler structure, and to obtain a stable opening characteristic. Further, a slit 161 is provided in a portion where the stopper 159 is formed, and the fuel that has passed through the annular gap 153b is released through the slit 162. The same effect can be obtained even if the slit 162 is provided on the end side of the valve body 151.

  In addition, in the modified example of the third embodiment, as shown in FIG. 7, the stopper 159 may be constituted by a member subjected to heat treatment or surface treatment separately from the pump body 1. By doing so, it is possible to improve the wear resistance and maintain a stable open characteristic for a long period of time. An example of the stopper 159 in FIG. 7 is preferably configured as shown in FIG. A fuel passage 181 is formed at the center of the circular member, and slits 162 are provided, for example, in four directions from the center. The valve body 1 stops at a stopper 159 on the member surface (right side in the figure).

  At the time of assembly, each part is assembled to the housing 156 and fixed by the stator 155b, and once unitized, the housing 156 is press-fitted into the pump body 1 and assembled, and the discharge joint 30 is attached. Thereby, assemblability improves and assembly cost can be reduced. Below, the assembly | attachment procedure of each component is demonstrated. First, the valve body 151 is inserted into the housing 156. Thereafter, the return spring 154 is inserted, and the stator 155b is press-fitted and fixed to form a unit.

  Further, in another modification of the third embodiment, as shown in FIG. 9, even when the annular gap 153b is sufficiently wide and does not have a fluid throttling effect, an improvement in assemblability by unitization can be expected. In addition, by adopting a structure in which the housing 156 is fixed to the pump body 1 by the press-fit portion 163, the guide portion 158 is firmly fixed to the pump body 1 as a result. Thereby, the eccentricity to the radial direction of a valve body can be suppressed, and high opening performance can be obtained stably.

  Also in the case of the third embodiment, the cylindrical wall portion formed in the relief passage is the housing 156, and the guide portion that slides in the wall portion and is formed integrally with the valve body corresponds to the guide portion 158. To do.

  With the above-described configuration, it is possible to realize a relief valve that stably exhibits high opening characteristics while maintaining volumetric efficiency even at high pressure, with a small and inexpensive structure.

  FIG. 10 shows a cross-sectional view of a relief valve according to Embodiment 4 of the present invention. In FIG. 10, 1 is a pump body, 150 is a seat portion, 152b is a vertical hole passage, 153a is a through hole, 154 is a return spring, 155b is a stator, 156 is a housing, 157 is a valve seat portion, and 158a and 158b are guide portions. 159 is a stopper, s60 is an intermediate chamber, 161 is a pressure receiving surface, and 162 is a slit.

  In the fourth embodiment, the guide portion 158 which is one place in the third embodiment is divided into two places 158a and 158b. By increasing the number of guide locations, eccentricity of the valve body in the radial direction can be suppressed with higher accuracy. Further, the fuel that has passed through the seat portion 150 passes through a through hole 153a provided as a fluid passage in the valve body 151, and is released. At this time, the through hole 153a has a fluid throttling effect as in the first embodiment, and pressure is stored in the intermediate chamber 160. Thereby, on the same principle as Example 1, a valve body lift increases and a high open characteristic can be acquired. In the shape of the valve body 151 in the present embodiment, the urging force of the return spring 154 is received by the stator 155b on the upstream side (the right side in the drawing) of the seat portion 150, so that a sufficient space for providing the through hole 153a is secured. In addition, since the penetration distance is short, an increase in processing cost can be suppressed.

  Also in the case of Example 4, the cylindrical wall portion formed in the relief passage is the housing 156, and the guide portion that slides in the wall portion and is formed integrally with the valve body corresponds to the guide portion 158. To do.

  By adopting the configuration as described above, a relief valve that exhibits a more stable and high opening characteristic while maintaining volumetric efficiency even at high pressure as in the case of the third embodiment is realized by a small and inexpensive structure. It is possible.

  Through the above embodiment, the fluid throttle is realized by making the cross-sectional area of the fluid passage smaller than the opening area of the seat portion when the valve body is fully open.

  According to the embodiment of the present invention configured as described above, the following effects can be obtained.

  A differential pressure in the valve opening direction is generated in the valve body in accordance with a differential pressure generated by a fluid throttle formed by a part of the valve body, and a high valve opening lift can be increased to obtain high opening performance.

  By guiding the valve body, the change in the cross-sectional area of the fluid throttle including a part of the valve body can be minimized. Thereby, it is possible to prevent the differential pressure generated before and after the fluid throttling from changing, and to stabilize the differential pressure. And valve body behavior and an opening characteristic can be stabilized.

  Further, by arranging the guide portion inside the return spring, it is possible to effectively use the space and to realize a reduction in size. By integrally forming the seat portion and the guide portion in the housing that forms a part of the fluid throttle, tolerance management such as a gap width becomes easier than in the case of separate formation. Thereby, the change in the cross-sectional area of the fluid throttle can be reduced at low cost, and the opening characteristics can be stabilized.

  Furthermore, the stopper for restricting the movement of the valve body can prevent the flow from being closed between the lines of the return spring even when the valve body lift increases, and a stable opening characteristic can be obtained. . By forming the stopper separately from the pump body with a heat treatment material or the like, the wear resistance can be improved, and a stable opening characteristic can be obtained even during long-term operation.

  The fluid throttle can be formed by an annular gap, a through hole, or the like, and the type can be flexibly selected according to the arrangement location. Thereby, useless space can be utilized and size reduction can be realized. Furthermore, it is good also as a structure once assembled as a unit outside a pump body at the time of an assembly. By doing so, the assemblability can be improved and the mass production cost can be reduced.

  The present invention is not limited to high-pressure fuel supply pumps for internal combustion engines, and can be widely used for various high-pressure pumps.

1: Body 2: Plunger 3: Retainer 4: Return spring 5: Solenoid valve 6: Tappet 7: Cam 8: Discharge valve 9: Suction passage 11: Pressurization chamber 12: Discharge passage 15: Relief passage 150: Seat portion 151: Valve body 153a: Through hole 153b: Annular gap 154: Return springs 155a and 155b: Stator 156: Housing 157: Valve seat portion 158: Guide portion 159: Stopper 160: Intermediate chamber 161: Pressure receiving surface 162: Slit 53: Common rail 54 : Injector 56: Pressure sensor

Claims (14)

In the body, a suction passage, a pressurizing chamber, and a discharge passage are sequentially formed from the upstream side, and an electromagnetic valve that determines the amount of fuel is arranged in the suction passage, and a discharge valve that restricts the flow direction of the fuel is arranged in the discharge passage, A relief valve is provided in a relief passage formed between the upstream and downstream of the discharge valve, and the relief valve has a seat portion that seals fuel by contacting a valve body and a valve seat portion provided in the relief passage. A high-pressure fuel supply pump that is formed and includes a fluid passage that includes a part of the valve body in addition to the seat portion to form a fluid throttle,
The relief valve further includes a cylindrical wall portion formed in the relief passage, and a guide portion that slides in the wall portion and is formed integrally with the valve body, and is guided in the radial direction of the valve body by the guide portion. A high-pressure fuel supply pump characterized by suppressing the eccentricity of the fuel. The high-pressure fuel supply pump according to claim 1,
A high-pressure fuel supply pump, characterized in that a fluid throttle is formed in which a cross-sectional area of the fluid passage is smaller than an opening area of the seat portion when the valve body is fully open. The high-pressure fuel supply pump according to claim 1 or 2,
A high-pressure fuel supply pump, wherein a return spring that urges the valve body toward the valve seat portion is provided, and the guide portion is disposed on an inner diameter side of the return spring. The high-pressure fuel supply pump according to any one of claims 1 to 3,
The high-pressure fuel supply pump, wherein the fluid throttle is formed by a gap between a part of the valve body and a housing, and the seat portion and the guide portion are integrally formed in the housing. The high-pressure fuel supply pump according to any one of claims 1 to 4,
A high-pressure fuel supply pump, wherein a stopper is provided to restrict the movement of the valve body before the return spring line comes into close contact when the valve body moves in the valve opening direction. The high-pressure fuel supply pump according to claim 5,
The high-pressure fuel supply pump, wherein the stopper is formed of a member that receives an urging force of the return spring. The high-pressure fuel supply pump according to claim 5,
The high-pressure fuel supply pump, wherein the stopper is formed directly on the pump body. The high-pressure fuel supply pump according to claim 5,
The high-pressure fuel supply pump, wherein the stopper is formed of a separate member from the pump body, and the separate member is subjected to heat treatment and surface treatment. The high-pressure fuel supply pump according to any one of claims 1 to 8,
A high-pressure fuel supply pump, wherein a fluid passage including the fluid throttle is formed by a through hole penetrating the valve body. The high-pressure fuel supply pump according to any one of claims 1 to 8,
A high-pressure fuel supply pump, wherein a fluid passage including the fluid throttle is formed on a side surface of the valve body. The high-pressure fuel supply pump according to any one of claims 1 to 10,
A high-pressure fuel supply pump, wherein the valve body is inserted into the housing, and then the return spring is fitted and fixed with a stator to form a unit, which is then fixed to the pump body and assembled. The high-pressure fuel supply pump according to claim 1 or 2,
The high-pressure fuel supply pump according to claim 1, wherein the cylindrical wall portion formed in the relief passage is a wall of the relief passage formed in the body or a housing fixed to the relief passage. The high-pressure fuel supply pump according to claim 1 or 2,
A high-pressure fuel supply pump characterized in that the cylindrical wall portion formed in the relief passage is a hollow inner tube formed in the relief passage. In the body, a suction passage, a pressurizing chamber, and a discharge passage are sequentially formed from the upstream side, and an electromagnetic valve that determines the amount of fuel is arranged in the suction passage, and a discharge valve that restricts the flow direction of the fuel is arranged in the discharge passage, A relief valve is provided in a relief passage formed between the upstream and downstream of the discharge valve, and the relief valve has a seat portion that seals fuel by contacting a valve body and a valve seat portion provided in the relief passage. A high-pressure fuel supply pump that is formed and includes a fluid passage that includes a part of the valve body in addition to the seat portion to form a fluid throttle,
A valve body and a valve seat part of the relief valve are provided on the upstream side of the discharge valve, and the inside of an inner cylinder fixed in the relief passage toward the downstream side of the discharge valve is connected to the valve body. The integrally formed guide portion slides and moves, and a return spring is disposed between the stator fixed to the end portion of the guide portion and the upstream fixed portion of the discharge valve. High pressure fuel supply pump characterized by

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