JP2008057544A - Pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the discharge pressure and load of a pump from becoming excessive. <P>SOLUTION: An eccentric cam 302 has a cam surface distance gradually-changing part 318 where the distance from an axis line to a cam surface gradually changes in the axis line direction. An engagement part 328 at which inclined surfaces are engaged with each other is arranged between a rotary shaft 324 of the eccentric cam 302 and an output shaft 326 of an electric motor 300. While a load imposed on a piston 304 is small, the rotary shaft 324 of the eccentric cam 302 is rotated with the rotation of the output shaft 326 of the electric motor 300. When the load imposed on the piston 304 is increased, the rotary shaft 324 is moved in the axis line direction by the effect of the inclined surface of the engagement part 328, and the eccentric cam 302 is moved in the axial direction. The stroke of the reciprocating motion of the piston 304 is reduced, and thereby the load of the pump is prevented from becoming excessive. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pump device, and more particularly to prevention of overload of the pump device.

In Patent Document 1, a pump that pumps up and pressurizes hydraulic fluid in a reservoir, an electric motor that drives the pump, a relief passage that connects a discharge side and a low pressure side of the pump, and a relief passage that is provided in the relief passage. And a relief device is described. In this pump device, when the discharge pressure of the pump becomes higher than the relief pressure of the relief valve, the working fluid is returned to the low pressure side through the relief valve. It is possible to prevent the discharge pressure of the pump from becoming excessive, and it is possible to prevent the load applied to the electric motor from becoming excessive.
JP-A-8-104214

  An object of the present invention is to prevent an excessive load on the pump device by another means.

Means and effects for solving the problems

The pump device according to claim 1 includes: (a) a piston fitted in the housing so as to be capable of reciprocating; (b) a driving device for reciprocating the piston; and (c) the piston and the driving device. And a driving force transmission device that transmits the driving force of the driving device to the piston, and sucks and discharges the hydraulic fluid by reciprocating motion of the piston, and a load applied to the pump device A transmission driving force suppression device that suppresses an increase in the transmission driving force, which is a driving force transmitted to the piston, exceeding the setting value while allowing the operation of the driving device to increase to a setting value. Including.
The driving force of the driving device is transmitted to the piston via the driving force transmission device. The transmission driving force, which is the driving force transmitted to the piston, increases as the load applied to the pump device increases. However, in the pump device described in this section, when the load increases to the set value, the transmission driving force is increased. The increase in force is suppressed. As a result, it is possible to prevent the pump discharge pressure from becoming excessive and to prevent the pump load from becoming excessive. Moreover, since it does not depend on the relief valve, it is possible to prevent the generation of noise that occurs when the hydraulic fluid passes through the relief valve. Furthermore, it is possible to prevent the load applied to the drive device from becoming excessive, and there is an advantage that the durability of the drive device can be improved.
For example, when the driving device is a direct current motor and a constant current is supplied to the direct current motor, the value obtained by multiplying the driving torque and the rotational speed is substantially constant. A transmission driving force corresponding to the driving torque is applied to the piston, and the piston is reciprocated according to the rotation speed. When the load applied to the pump device increases, the transmission driving force applied to the piston increases, the driving torque increases, and the rotational speed decreases.
When the load applied to the pump device increases to the set value, an increase in the transmission driving force is suppressed even when a constant current is supplied to the electric motor. The transmission drive force will not increase with the increase in load, and the relationship between the load and the transmission drive force will be smaller than before the load reached the set value, or the transmission drive force However, the load may not increase from the magnitude when the load reaches the set value. The state in which the DC motor continues to rotate in this state is one mode of “a state in which the operation of the drive device is permitted”.

Patentable invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, or inventions of different concepts) will be illustrated and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating understanding of the claimable invention, and is not intended to limit the set of components constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  Of the following items, (1) corresponds to claim 1, (3) to (6) correspond to claims 2 to 5, (8) corresponds to claim 6, Claim (10) corresponds to claim 7.

(1) a housing;
A piston fitted in the housing so as to be able to reciprocate;
A drive for reciprocating the piston;
A pump device that is provided between the piston and the drive device and includes a drive force transmission device that transmits the drive force of the drive device to the piston, and performs suction and discharge of the hydraulic fluid by reciprocating motion of the piston,
When the load applied to the pump device increases to a set value, the operation of the drive device is allowed and the transmission drive force, which is the drive force transmitted to the piston, is prevented from increasing beyond the set value. A pump device comprising a transmission driving force suppressing device.
(2) The pump device according to (1), wherein the driving force transmission device includes a cam that is provided with an outer peripheral surface facing the piston and is rotated about one axis by the driving device.
For example, when the drive device is an electric motor, the cam is rotated with the rotation of the electric motor, and the piston facing the outer peripheral surface of the cam is linearly reciprocated. In this aspect, the driving force transmission device is also a motion conversion device.
(3) The pump device according to (2), wherein the cam includes a portion having a large distance and a portion having a small distance from the axis to the cam surface at positions separated in the axial direction.
When the piston faces a portion where the distance from the cam axis to the cam surface is large and when the piston faces a portion where the distance from the axis to the cam surface is small, facing the portion where the distance from the axis to the cam surface is small Since the stroke of the reciprocating motion of the piston becomes smaller, the maximum hydraulic pressure in the pump chamber during one reciprocating motion of the piston becomes lower, and the transmission driving force applied to the piston becomes smaller.
If the portion of the piston facing the cam is changed from a portion having a large distance from the axis to the cam surface to a portion having a small distance, the transmission driving force applied to the piston is reduced.
The cam can be an eccentric cam, but is not limited thereto.
(4) The pump device according to (3), wherein at least a part of the cam has a portion where the distance from the axis to the cam surface gradually changes in the axial direction.
The cam included in the driving force transmission device described in this section has a cam surface distance gradually changing portion in which the distance from the axis to the cam surface gradually changes in the axial direction. When the piston is opposed to the cam surface distance gradually changing portion of the cam, if the cam is moved in a direction parallel to one axis with respect to the piston, the distance from the axis of the portion facing the piston to the cam surface gradually changes. The stroke of the reciprocating motion of the piston is gradually changed. When the distance from the axis to the cam surface is moved in a direction that gradually decreases, the transmission driving force applied to the piston also gradually decreases.
The cam may have a gradual change in the distance from the axis to the cam surface as a whole or a part thereof. In other words, the cam surface distance gradually changing portion and the cam surface distance constant portion may be included, or the cam surface distance constant portion may not be included. The cam surface distance gradually changing portion is provided in a state in which the eccentric amount of the portion facing the piston is reduced by the movement of the cam in the direction parallel to the one axis with respect to the piston when the load applied to the pump device increases to the set value. In this case, the cam surface distance gradually changing portion can be referred to as a cam surface distance gradually decreasing portion.
(5) When the load of the pump device increases to a set value, the transmission driving force suppression device is parallel to the one axis of the cam in a direction in which the movement amount of the piston accompanying the rotation of the cam decreases. The pump device according to item (4), including an axial direction movement allowance device that allows movement in any direction.
If the cam is moved in a direction parallel to one axis, the portion of the cam facing the piston changes, and the distance from the axis of that portion to the cam surface changes. In the pump device described in this section, the cam is moved in such a direction that the distance from the axis of the portion facing the piston to the cam surface is reduced, and the amount of movement of the piston accompanying the rotation of the cam is reduced. The applied transmission driving force is reduced.
As described in the next section, when the urging device is provided in the pump device, the cam is parallel to the uniaxial line of the force in the direction parallel to the uniaxial line by the driving device and the force in the direction crossing the uniaxial line by the piston. At least one of the components in the different directions and the force in the direction parallel to the one axis by the biasing device act in opposite directions.
Since the force applied by the driving device has a magnitude corresponding to the force applied by the piston, it can be considered that the force applied by the driving device and the force applied by the piston are both in accordance with the load of the pump. Therefore, it can be considered that the force applied by the urging device and the force corresponding to the load of the pump are applied to the cam. In this case, when the force according to the load of the pump becomes larger than the force by the urging device, the cam is moved in the axial direction against the urging force.
Conversely, when the force by the urging device becomes larger than the force according to the load of the pump, the cam is moved in the axial direction by the urging force in the direction opposite to that described above. The cam is often returned to its original position.
(6) The driving force transmission device includes: (a) an engagement device that engages an output shaft of the driving device and a rotating shaft of the cam; and (b) driving the rotating shaft of the cam to the cam. And a biasing device that applies a biasing force in a direction of pressing against the output shaft of the device.
A biasing force is applied to the cam, thereby pressing the rotating shaft of the cam against the output shaft of the drive device. The cam rotation shaft is restrained from being separated from the output shaft of the drive device, and the drive torque of the drive device output shaft is transmitted to the cam rotation shaft.
(7) The engaging device includes an engaging portion that engages the output shaft and the rotating shaft in a state that allows relative movement in a direction parallel to the one axis and prevents relative rotation (6). ) Pump device.
For example, the output shaft and the rotation shaft are engaged by fitting a protrusion extending in a direction parallel to the uniaxial line provided on one of the shaft and a groove extending in a direction parallel to the uniaxial line provided on the other. When they are combined, they can be rotated together and relatively moved in a direction parallel to one axis. An example of this type of engaging portion is a spline engaging portion.
For example, in a state where the piston faces the cam surface distance gradually changing portion of the cam, the cam has a force in a direction parallel to one axis applied by the biasing device and a force in a direction crossing the one axis applied by the piston. The component in the direction parallel to the one axis acts. When the component in the direction parallel to one axis of the force by the piston becomes larger than the biasing force, the cam is moved against the biasing force. In the pump device described in this section, the engagement device can be considered as one component of the axial relative movement allowance device.
(8) When the axial movement allowance device increases a component in a direction parallel to one axis of the force in a direction intersecting the one axis applied to the cam by the piston to a set value, the one axis of the cam The pump device according to the item (7), which allows movement in a direction parallel to the head.
In the pump device described in this section, the cam is moved in a direction parallel to one axis based on the force applied to the cam by the piston.
(9) When the axial movement allowance device increases a component in a direction parallel to one axis of the force in a direction intersecting the one axis applied to the cam by the piston to a set value, the one axis of the cam An axial movement allowance device that allows movement in a direction parallel to the driving force transmission device, (a) provided on the output shaft of the drive device and the rotating shaft of the cam, respectively, and orthogonal to the one axis line An engaging device that includes an inclined surface that is inclined with respect to a flat surface and that engages the output shaft and the rotating shaft by engaging the inclined surfaces, and (b) the cam has a rotating shaft of the cam. And a biasing device that applies a biasing force in a direction of pressing the output against the output shaft of the driving device.
When the load applied to the pump is normal, no slip occurs between the inclined surfaces of the engaging portion, and the rotating shaft rotates together with the output shaft. Therefore, the piston of the pump device can be normally reciprocated by the cam. On the other hand, when the load applied to the pump device reaches a set value, slip occurs between the inclined surfaces, and the rotating shaft is moved in the axial direction against the urging force of the urging device by the effect of the inclined surface. As a result, the cam surface distance gradually changing portion where the distance from the cam axis to the cam surface gradually opposes the piston of the pump device, and the movement amount of the piston becomes small or zero. In the pump device described in this section, the engagement device can be considered as one component of the axial relative movement allowance device.
(10) The drive force transmission device is configured to move the cam in a direction parallel to the one axis of the cam according to relative rotation between the output shaft of the drive device and the rotation shaft of the cam. The pump device according to item (9).

(11) a housing;
A piston fitted in the housing so as to be able to reciprocate;
A pump chamber formed in front of the piston of the housing;
A suction valve provided at the suction port of the pump chamber;
A pump device that includes a discharge valve provided at a discharge port connecting the pump chamber and the discharge chamber, and performs suction and discharge of hydraulic fluid in the pump chamber in accordance with the reciprocating motion of the piston,
A pump device comprising a relief valve provided inside the housing and permitting outflow of hydraulic fluid from a high pressure side to a low pressure side when a differential pressure across the front and rear becomes equal to or higher than a set pressure.
According to the relief valve, it is possible to prevent the hydraulic pressure on the high pressure side of the relief valve, for example, the discharge chamber or the pump chamber from becoming excessive, and it is possible to prevent the load applied to the pump from becoming excessive. .
In the pump device described in this section, the relief valve is provided inside the housing. When it is provided outside the housing, relief pipes and pipe joints are required, which increases the number of parts. However, if it is provided inside the housing, relief pipes and pipe joints are not required, reducing costs. Can be achieved. The relief valve may be provided in the housing itself, or may be provided in a member provided inside the housing such as a piston.
The technical features described in any one of items (1) to (10) can be employed in the pump device described in this item.
(12) The relief valve is provided in a portion of the housing between the pump chamber and the discharge chamber, and when the hydraulic pressure in the discharge chamber is higher than the set pressure by the hydraulic pressure in the pump chamber, The pump device according to item (11), which allows the flow of hydraulic fluid from the discharge chamber to the pump chamber.
In the pump device described in this section, when the hydraulic pressure in the discharge chamber becomes higher than the relief pressure than the hydraulic pressure in the pump chamber, the relief valve is opened and the hydraulic fluid in the discharge chamber is allowed to flow into the pump chamber. . This prevents the liquid pressure in the discharge chamber from becoming excessive.
(13) A valve seat provided on a valve seat member, at least a part of which is movable relative to the housing, and a valve element provided so as to be seated and separated from the valve seat. The pump device according to (11) or (12).
(14) The relief valve includes the valve seat member and the housing, and when the hydraulic pressure in the discharge chamber is higher than a set pressure by the hydraulic pressure in the pump chamber, the valve seat member is attached to the housing. The pump device according to item (13), which is opened by being moved relative to the pump.
In the pump device described in this section, the discharge valve and the relief valve are provided in parallel. Further, the valve seat member in which the valve seat of the discharge valve is formed is a valve element. Therefore, an increase in the number of parts when the relief valve is provided can be avoided, and an increase in the diameter of the cylinder can be avoided.
In the normal operating state of the pump, the relief valve is closed. In the closed state of the relief valve, the discharge valve and the suction valve are opened and closed as the piston reciprocates.
On the other hand, for example, when the liquid passage on the discharge side of the pump device is blocked due to a valve closing failure or the like, the liquid pressure on the discharge side should be high and the pump operation should be stopped. When the pump operation is continued due to an abnormality of the pressure sensor or the like, the hydraulic pressure in the discharge chamber becomes an abnormal height. It is so high that it cannot be in the normal operating state of the pump. When the hydraulic pressure in the discharge chamber becomes higher than the set pressure by the hydraulic pressure in the pump chamber, the relief valve is opened. The hydraulic fluid is allowed to flow from the discharge chamber to the pump chamber, and the hydraulic pressure in the discharge chamber decreases.
The hydraulic pressure in the pump chamber increases during the forward travel of the piston. When the hydraulic pressure in the pump chamber becomes higher than the valve opening pressure by higher than the hydraulic pressure in the discharge chamber, the discharge valve is opened and the hydraulic fluid in the pump chamber is supplied to the discharge chamber. In the reverse stroke of the piston, the hydraulic pressure decreases as the volume of the pump chamber increases, so that the discharge valve is closed. Further, when the hydraulic pressure in the discharge chamber is higher than the relief pressure than the hydraulic pressure in the pump chamber, the relief valve is opened. The hydraulic fluid in the discharge chamber is caused to flow into the pump chamber, and the hydraulic pressure in the discharge chamber decreases. In the reverse stroke, since the hydraulic pressure in the pump chamber is low, the hydraulic pressure in the discharge chamber is lowered by connecting the discharge chamber and the pump chamber. As a result, when the hydraulic pressure difference between the discharge chamber and the pump chamber is reduced, the relief valve is closed. In the reverse stroke, if the hydraulic pressure in the pump chamber is higher than the hydraulic pressure in the suction passage, the suction valve will not be opened, but if the pressure is lower than the hydraulic pressure in the suction passage, the suction valve will be opened and the pump will be opened. Hydraulic fluid is drawn into the chamber.
Thus, the relief valve and the discharge valve are opened and closed with the reciprocating motion of the piston.
(15) The pump device according to (14), wherein the valve seat member is provided to be movable relative to the housing in a direction parallel to the axis of the pump.
(16) The pump device according to (15), wherein the valve seat member is provided so as to be relatively movable with respect to the housing in a direction intersecting an axis of the pump.
The relief valve is opened and closed by moving the valve seat member relative to the housing. The valve seat member may be provided so as to be relatively movable in a direction parallel to the axis, or may be provided so as to be relatively movable in a direction crossing the axis. When relative movement is possible in the intersecting direction, it is desirable that relative movement is possible in the direction perpendicular to the axis.
(17) A suction passage that connects the suction port and the low pressure chamber is provided in the piston body, and the suction valve is a valve seat member that is at least partially movable relative to the piston body. A valve seat provided, and a valve element provided so as to be seated / separated from the valve seat, wherein the relief valve includes the valve seat member and the piston body, and the hydraulic pressure in the pump chamber The pump device according to any one of (11) to (16), wherein the valve seat member is opened by being moved relative to the piston main body when the pressure becomes higher than a set pressure. .
In the pump device described in this section, the relief valve is provided in parallel with the suction valve. When the relief valve is switched to the open state, the hydraulic fluid in the pump chamber is allowed to flow into the low pressure chamber. As a result, the hydraulic pressure in the pump chamber is prevented from becoming excessive, and the hydraulic pressure in the discharge chamber is prevented from becoming excessive.
The relief valve may be provided in parallel with the intake valve or in parallel with the discharge valve.Hereinafter, a relief valve provided in parallel with the intake valve is provided in parallel with the intake side relief valve and the discharge valve. These relief valves are referred to as discharge-side relief valves to distinguish them.
When the hydraulic pressure in the discharge chamber is abnormally high, the suction side relief valve is opened before the discharge valve in the forward travel of the piston. Prior to the difference between the hydraulic pressure in the pump chamber and the hydraulic pressure in the discharge chamber becoming greater than or equal to the opening pressure of the discharge valve, the difference between the hydraulic pressure in the pump chamber and the hydraulic pressure in the low-pressure chamber opens the suction side relief valve. It becomes more than the valve pressure. As a result, the hydraulic pressure in the pump chamber is prevented from becoming excessive, and the hydraulic pressure in the discharge chamber is prevented from becoming higher. In the reverse stroke of the piston, the volume of the pump chamber is increased, the hydraulic pressure is decreased, and the suction side relief valve is closed. Further, when the hydraulic pressure in the pump chamber becomes lower than the hydraulic pressure in the low pressure chamber, the suction valve is opened and the working fluid is sucked.
Thus, in the pump device described in this section, the suction side relief valve and the suction valve are opened and closed with the reciprocating motion of the piston.
(18) a housing;
A piston fitted in the housing so as to be able to reciprocate;
A drive for reciprocating the piston;
A pump device that is provided between the piston and the drive device and includes a drive force transmission device that transmits the drive force of the drive device to the piston, and that sucks and discharges hydraulic fluid by reciprocating motion of the piston,
A stroke reduction device that reduces the stroke of the reciprocating motion of the piston smaller than that when the load is smaller than a set value while allowing the operation of the drive device when the load applied to the pump device exceeds a set value. A pump device comprising:
If the stroke of the piston is reduced, it is possible to prevent the discharge pressure from becoming excessive.
The technical features described in any one of items (1) to (17) can be employed in the pump device described in this item.

Hereinafter, a pump device according to an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, the pump device pumps up the hydraulic fluid and pressurizes it, and is used in a vehicle brake device.
In FIG. 3, 10 is a power hydraulic pressure source, and 12 is a master cylinder as a manual hydraulic pressure source. The master cylinder 12 includes a pressurizing piston linked to a brake pedal 14 as a brake operating member, and a hydraulic pressure corresponding to the operating state of the brake pedal 14 by the driver is present in the pressurizing chamber in front of the pressurizing piston. Be generated.

  The power hydraulic pressure source 10 includes a pump device 20, an accumulator 24, and the like. The pump device 20 includes a pump 30 and a pump motor 32 that drives the pump 30. The pump 30 pumps up the hydraulic fluid in the reservoir 34 as a hydraulic fluid supply source, pressurizes and discharges the hydraulic fluid, and the hydraulic fluid discharged from the pump 30 is stored in the accumulator 24. The pump motor 32 is controlled by a control unit 38 mainly composed of a computer so that the hydraulic pressure of the hydraulic fluid stored in the accumulator 24 is within a predetermined setting range. The operation of the pump motor 32 is stopped when the upper limit pressure of the set range is reached, and is activated when the pressure falls below the lower limit pressure. The hydraulic pressure of the hydraulic fluid stored in the accumulator 24 is detected by a hydraulic pressure sensor 36.

A brake cylinder 42 is connected to the fluid passage 40 extended from the master cylinder 12, and the brake 44 is operated by the fluid pressure of the brake cylinder 42, and the rotation of the wheels 46 is suppressed. The liquid passage 40 is provided with a master shut-off valve 50 and a holding valve 52, and a liquid passage 54 extended from the power hydraulic pressure source 10 is connected between the master shut-off valve 50 and the holding valve 52. . A pressure reducing valve 56 is provided between the brake cylinder 42 and the reservoir 34. The master shut-off valve 50, the holding valve 52, the pressure reducing valve 56 and the like are controlled based on a command from the control device 38.
When the brake pedal 14 is depressed, the master cutoff valve 50 is switched to the cutoff state. With the brake cylinder 42 disconnected from the master cylinder 12, the hydraulic pressure of the brake cylinder 42 is controlled by the hydraulic pressure of the power hydraulic pressure source 10. The brake cylinder 42 is supplied with hydraulic fluid having a hydraulic pressure corresponding to the brake operation force, and the brake 44 is operated. The brake operation force is detected by the operation force sensor 58, and the hydraulic pressure in the brake cylinder 42 is detected by the brake hydraulic pressure sensor 60.
The hydraulic pressure in the brake cylinder 42 can be controlled by controlling the pump motor 32. In this case, the accumulator 24 is not essential. In addition to the holding valve 52 and the pressure reducing valve 56, a hydraulic pressure control valve device is provided between the accumulator 24 and the holding valve 52. As a general rule, the hydraulic pressure control is performed when the holding valve 52 is open and the pressure reducing valve 56 is closed. The hydraulic pressure of the brake cylinder can be controlled by controlling the valve device.

  The pump 30 included in the pump device 20 can be a plunger pump 30 as shown in FIG. In the plunger pump 30, a piston 80 as a movable member is slidably fitted to a cylinder housing 82. The cylinder 82 is attached to the housing of the entire pump device (not shown). In the present embodiment, the housing 82 is a member suitable for sliding of the piston 80.

A pump chamber 84 is formed in front of the piston 80 of the housing 82. The piston 80 is opposed to the pump chamber 84 at one end, and is opposed to a low pressure side liquid chamber 86 (hereinafter referred to as a low pressure chamber) at the other end. The low pressure chamber 86 is communicated with the reservoir 34. Further, the other end portion faces an eccentric cam 88 that rotates as the pump motor 32 rotates, and one end receives a biasing force of a spring 90 as a biasing device. A roller 88b is attached to the outer peripheral surface of the eccentric cam 88 through a bearing 88a so as to be relatively rotatable, and the roller 88b contacts the other end of the piston 80.
Since the piston 80 is pressed against the roller 88b by the spring 90, the piston 80 is kept in contact with the roller 88b during the reciprocating motion. In the present embodiment, the pump motor 32 constitutes a drive device, and the eccentric cam 88, the roller 88b and the like constitute a drive force transmission device.

A discharge chamber 100 is formed in front of the pump chamber 84 of the housing 82. A discharge valve 102 is provided at the discharge port between the pump chamber 84 and the discharge chamber 100. The discharge valve 102 includes a valve seat 104, a valve element 106 that can be seated / separated from the valve seat 104, and a spring 108 that biases the valve element 106 in a direction in which the valve element 106 is seated on the valve seat 104. . The valve seat 104 is formed around the discharge port.
When the hydraulic pressure in the pump chamber 84 becomes higher than the hydraulic pressure in the discharge chamber 100 by a set pressure or more according to the set load of the spring 108, the valve element 106 is separated from the valve seat 104 against the urging force of the spring 108 and discharged. The valve 102 is switched to the open state. The hydraulic fluid in the pump chamber 84 is discharged toward the discharge chamber 100, and the hydraulic fluid in the discharge chamber 100 is supplied to the liquid passage 54. The spring 108 is held by the spring retainer 110. The spring retainer 110 is provided with a through hole, and the discharge chamber 100 is communicated with the liquid passage 54.
A suction passage 114 extending generally in the axial direction is formed inside the piston 80, and a suction valve 116 is provided at the suction port of the suction passage 114. The suction valve 116 includes a valve seat 118 provided at the suction port of the suction passage 114 of the piston 80 and a valve element 120 that can be seated and separated from the valve seat 118. When the hydraulic pressure in the pump chamber 84 becomes lower than the hydraulic pressure in the liquid chamber 86, the valve element 120 is separated from the valve seat 118 and the working fluid is sucked into the pump chamber 84. Since the piston 80 is provided with the valve element holding member 122, the movement limit of the valve element 120 is defined.

In the present embodiment, a discharge side relief valve 130 is provided in parallel with the discharge valve 102. The discharge side relief valve 130 includes a valve seat member 132 provided with the valve seat 104 of the discharge valve 102 and a housing 82. The valve seat member 132 is provided so as to be movable relative to the housing 82. In the discharge side relief valve 130, the valve seat member 132 is a valve element, and the contact portion of the housing 82 with the valve seat member 132 is a valve seat 134. The valve seat member 132 is biased by a spring 136 in a direction in which the valve seat member 132 is seated on a valve seat 134 provided in the housing 82. In a state where the piston 80 is moving backward, when the hydraulic pressure in the discharge chamber 100 becomes higher than the hydraulic pressure in the pump chamber 84 by a set pressure determined according to the set load of the spring 136, the valve seat member 132 becomes biased by the spring 136. Accordingly, the discharge chamber 100 and the pump chamber 84 are communicated with each other. In a state where the piston 80 is moving backward, the hydraulic pressure in the pump chamber 84 is reduced to almost atmospheric pressure, so that the hydraulic pressure in the discharge chamber 100 is also reduced by connecting the discharge chamber 100 and the pump chamber 84. It is done.
As shown in the figure, the spring 136 is provided between the valve seat member 132 and the cylinder housing 82, and the spring 90 is provided between the piston 80 and the valve seat member 132. The urging force of the spring 90 is smaller than the urging force of the spring 136, and when the hydraulic pressure in the discharge chamber 100 is normal, the valve seat member 132 resists the urging force of the spring 136. The spring 90 is expanded and contracted with the reciprocating motion of the piston 80, while being not separated from the beam 134.

The operation of the pump device 20 configured as described above will be described. The piston 80 is reciprocated with the rotation of the eccentric cam 88 driven by the pump motor 32.
The position where the piston 80 protrudes most backward from the cylinder housing 82 is the bottom dead center, which is the suction end position. In the suction stroke toward the suction end position, the piston 80 is retracted while being pressed against the rotating body 88b of the eccentric cam 88 by the biasing force of the spring 90, and the hydraulic pressure in the suction passage 114 is determined by the hydraulic pressure in the pump chamber 84. Therefore, the suction valve 116 is opened, and the working fluid is sucked into the pump chamber 84 from the suction passage 114 through the suction valve 116. Thereafter, the piston 80 is advanced by the eccentric cam 88 against the urging force of the spring 90. Thereby, the volume of the pump chamber 84 is reduced and the hydraulic pressure is increased. The valve element 120 is seated on the valve seat 118 by the hydraulic pressure in the pump chamber 84, and the suction valve 116 is closed.
The position where the piston 80 has advanced most is the top dead center, which is the discharge end position. The volume of the pump chamber 84 is minimized, and the hydraulic pressure is highest during one reciprocating motion of the piston 80. When the hydraulic pressure difference between the pump chamber 84 and the discharge chamber 100 becomes higher than the urging force of the spring 108, the discharge valve 102 is opened and the hydraulic fluid in the pump chamber 94 is discharged to the discharge chamber 100.

  The piston 80 reaches top dead center at the position where the eccentric amount of the eccentric cam 88 is the maximum (the position where the distance from the rotation center axis L of the eccentric cam 88 is the maximum), and thereafter, the force in the forward direction is applied to the piston 80 by the pump motor 32. Will not be added. The piston 80 is returned to the suction end position as the eccentric cam 88 rotates while being pressed against the rotating body 88b of the eccentric cam 88 by the biasing force of the spring 90. Thereafter, the same operation is repeated, and the working fluid sucked from the reservoir 34 is pressurized and supplied to the accumulator 24.

  For example, when the hydraulic fluid discharged from the pump 30 is not supplied to the brake cylinder 42 due to the closing failure of the holding valve 52, even if the hydraulic pressure of the accumulator 24 becomes higher than the set pressure due to the failure of the accumulator pressure sensor 36. For example, when a command to stop the operation of the pump 30 is not output, the hydraulic pressure in the discharge chamber 100 becomes abnormally high. On the other hand, in the suction stroke of the piston 80, the volume of the pump chamber 84 is increased, so that the hydraulic pressure in the pump chamber 84 is lowered. When the hydraulic pressure in the discharge chamber 100 becomes higher than the set pressure by the hydraulic pressure in the pump chamber 84, the discharge side relief valve 130 is opened as shown in FIG. The hydraulic fluid in the discharge chamber 100 is caused to flow into the pump chamber 84, and the hydraulic pressure in the discharge chamber 100 is lowered. Thereby, the discharge side relief valve 130 returns to the closed state.

Further, as the piston 80 moves backward, the volume of the pump chamber 84 increases and the hydraulic pressure in the pump chamber 84 decreases. However, even at the suction end position, the hydraulic pressure in the pump chamber 84 is higher in the liquid chamber 86. When the pressure is higher than the hydraulic pressure, the suction valve 116 remains closed, and the hydraulic fluid is not sucked into the pump chamber 84.
When the piston 80 is moved forward and the hydraulic pressure in the pump chamber 84 becomes higher than the valve opening pressure than the hydraulic pressure in the discharge chamber 100, the discharge valve 102 is opened and hydraulic fluid is discharged from the pump chamber 84 to the discharge chamber 100. The Next, when the piston 80 is retracted, the discharge side relief valve 130 is opened, and the hydraulic fluid in the discharge chamber 100 is caused to flow into the pump chamber 84. Thereafter, the same operation is repeated. As the piston 80 reciprocates, the discharge-side relief valve 130 and the discharge valve 102 are opened and closed, and the hydraulic pressure in the discharge chamber 100 can be prevented from becoming excessive.

  As described above, in this embodiment, the relief valve 130 is provided inside the housing 82 of the pump 30. Since the relief passage and the like which are indispensable when provided outside the housing 82 are not required, the cost can be reduced.

  The relief valve can have a structure shown in FIG. In this embodiment, as shown in FIG. 5, a part of the valve seat 204 of the discharge valve 202 is provided on a valve seat member 206 that can move relative to the housing 82 in a direction perpendicular to the axis M of the pump. . Half of the valve seat 204 is formed in the housing 82 and the other half is formed in the valve seat member 206. Further, a portion corresponding to the valve seat member 206 of the spring retainer 209 is cut out, and a spring 210 is provided between the portion of the valve seat member 206 protruding from the cutout of the spring retainer 209 and the housing 82. In this embodiment, a leaf spring is used as the spring 210. The valve seat member 206 serves as a valve element, and the contact portion 212 that contacts the valve seat member 206 of the housing 82 serves as a valve seat. The discharge side relief valve is formed by the valve element 206, the valve seat 212, the spring 210, and the like. 214 is configured.

In the discharge valve 202, when the valve element 216 is seated on the valve seat 204, the hydraulic pressure in the pump chamber 84 acts on the part corresponding to the discharge port side from the part of the valve element 216 in contact with the valve seat 204. The fluid pressure of the discharge chamber 100 acts on the other parts. The urging force of the spring 108 is also applied to the valve element 216. The force applied to the valve element 216 acts on the valve seat member 206 at a tangent to the valve seat 204.
Further, the hydraulic pressure of the discharge chamber 100 also acts on a surface 220 (a portion on the outer peripheral side of the tangent to the valve element 216) facing the discharge chamber 100 inside the valve seat member 206. On the other hand, the hydraulic pressure of the discharge chamber 100 acts on the outer surface 222 of the valve seat member 206 and the urging force of the spring 210 acts.
As described above, force acts on the valve seat member 206. In the valve seat member 206, the force in the direction orthogonal to the axis M and in the outward direction is greater than the force in the inward direction. When it becomes larger, the valve seat member 206 is moved relative to the valve seat 212 of the housing 82, and the discharge side relief valve 214 is opened.

In the present embodiment, the valve element holding member 226 of the suction valve 116 includes a tapered portion 228. The tapered portion 228 has a tapered surface whose inner diameter decreases as the distance from the piston 80 increases. When the hydraulic pressure in the suction passage 114 becomes higher than the hydraulic pressure in the pump chamber 84, the valve element 120 is separated from the valve seat 118 and hydraulic fluid is supplied to the pump chamber 84. In this case, the valve element 120 is not separated from the position in contact with the tapered surface, and the taper portion 228 can suppress misalignment in a state where the valve element 120 is separated from the valve seat 118. When the hydraulic pressure in the pump chamber 84 becomes higher than the hydraulic pressure in the suction passage 114, the valve element 120 is seated on the valve seat 118. In this case, the valve element 120 can be reliably seated on the valve seat 118. In this way, if the valve-holding member 226 has the tapered portion 228, the misalignment of the valve 120 can be suppressed without providing a spring that biases the valve 120 in the direction in which the valve 120 is seated on the valve seat 118. can do.
The technique in which the valve-holding member 226 has the tapered surface 228 can also be employed in the first embodiment.

  In addition, the relief valve can be provided in parallel with the suction valve 116 as shown in FIG. The suction side relief valve 250 provided in parallel with the suction valve 116 is similar in structure to the discharge side relief valve 130, and includes a valve seat member 252 provided with a valve seat 118 of the suction valve 116 and a valve of the piston main body 254. And a portion 256 that contacts the seat member 252. The valve seat member 252 is provided on the piston main body 254 so as to be relatively movable. The valve seat member 252 serves as a valve element, and the contact portion 256 of the piston main body 254 serves as a valve seat. The valve seat member 252 is biased by a spring 258 in a direction in which the valve seat member 252 is seated on the valve seat 256. When the hydraulic pressure in the pump chamber 84 becomes higher than the hydraulic pressure in the low pressure chamber 86 (suction passage 114) by a set pressure corresponding to the set load of the spring 258, the suction side relief valve 250 is opened as shown in FIG. Thus, the pump chamber 84 is communicated with the low pressure chamber 86, and the working fluid in the pump chamber 84 flows into the low pressure chamber 86. The hydraulic pressure in the pump chamber 84 is reduced and the hydraulic pressure in the discharge chamber 100 is prevented from becoming excessive.

  In the normal operation state of the pump, the suction side relief valve 250 is kept closed. When the hydraulic pressure in the discharge chamber 100 is abnormally high, the suction side relief valve 250 is opened before the discharge valve 116 in the forward travel of the piston 80. As the piston 80 moves forward, the hydraulic pressure in the pump chamber 84 increases, but when the hydraulic pressure in the discharge chamber 100 is abnormally high, the difference between the hydraulic pressure in the discharge chamber 100 and the hydraulic pressure in the pump chamber 84 is discharged. Prior to reaching the valve opening pressure of the valve 116, the difference between the hydraulic pressure in the pump chamber 84 and the hydraulic pressure in the low pressure chamber 86 becomes equal to or higher than the relief pressure of the suction side relief valve 250. In the backward stroke of the piston 80, hydraulic fluid is sucked into the pump chamber 84 from the low pressure chamber 86 as the volume of the pump chamber 84 increases. Thus, in this embodiment, the suction side relief valve 250 and the suction valve 116 are opened and closed with the reciprocating motion of the piston 80, but the discharge valve 102 is kept closed. Thereby, it is possible to satisfactorily prevent the liquid pressure in the discharge chamber 100 from becoming excessive.

Furthermore, it is possible to prevent the pump discharge pressure from becoming excessive by suppressing the transmission driving force applied to the piston by the eccentric cam.
In FIG. 8, 300 is an electric motor as a driving device, 302 is an eccentric cam, and in the pump device, the piston 304 of the pump 30 is disposed in a state facing the outer peripheral surface of the eccentric cam 302. The eccentric cam 302 is rotated around the axis L by the electric motor 300. The eccentric cam 302 is rotated with the rotation of the electric motor 300, whereby the piston 304 is linearly reciprocated in the direction orthogonal to the axis L.
On the other hand, as shown in FIG. 9, a ball 314 is disposed at the end of the piston 304 facing the eccentric cam 302 so as to be rotatable relative to the main body 312 of the piston 304. The piston 304 is in contact with the outer peripheral surface of the eccentric cam 302 at the ball 314. Even if the outer peripheral surface of the eccentric cam 302 is inclined with respect to the axis L, the contact state with the eccentric cam 302 can be satisfactorily maintained.

The eccentric cam 302 can also be referred to as an eccentric amount gradually changing portion in which the eccentric amount is gradually changed in the axis L direction (a cam surface distance gradually changing portion in which the distance from the axis L of the cam surface is gradually changed in the axis L direction). ) 318, and an eccentric amount constant portion (also referred to as a cam surface distance constant portion) 320, 322 having a constant eccentric amount. Eccentric amount constant portions 320 and 322 are provided on both sides of the eccentric amount gradually changing portion 318, respectively. In the eccentric cam 302, the eccentric amount constant portion 320 has the largest eccentric amount, the eccentric amount constant portion 322 has the smallest eccentric amount, and the eccentric amount gradually decreasing portion 318 has an eccentric amount from the side where the eccentric amount constant portion 320 is located. The amount of eccentricity is reduced toward the side where the constant portion 322 is located. The amount of eccentricity in the constant amount of eccentricity 322 can be zero, and in that case, the constant amount of eccentricity 322 can be referred to as a cylindrical portion. In the present embodiment, the eccentricity constant portion 322 having the smallest eccentricity is provided on the electric motor 300 side. It is not essential to provide the constant eccentricity portion 322.
In the state in which the piston 304 faces the constant eccentricity portion 320 and the state in which the piston 304 faces the constant eccentricity portion 322, the stroke (amplitude) of the reciprocating motion of the piston 304 is smaller in the state facing the constant eccentricity portion 322. Become. Therefore, the transmission driving force applied to the piston 304 when the discharge pressure is the same is reduced. In a state where the piston 304 faces the eccentricity gradually changing portion 318, the stroke is gradually changed as the axis L of the eccentric cam 302 moves.

  The eccentric cam 302 is rotated by the rotation shaft 324, and the rotation shaft 324 is connected to the output shaft 326 of the electric motor 300 via the engaging portion 328. The rotating shaft 324 and the output shaft 326 are held in the pump device main body 340 via bearings 342 and 344 so as to be relatively rotatable. The bearing 344 is held so as to be movable relative to the apparatus main body 340. A spring 346 as an urging device is provided between the bearing 344 and the apparatus main body 340. The spring 346 applies a biasing force in a direction parallel to the axis L and in a direction in which the rotating shaft 324 is pressed against the output shaft 326.

As shown in FIG. 10, the engaging portion 328 is engaged with an inclined surface 352 inclined with respect to an axis L provided on the rotating shaft 324 and an inclined surface 354 provided on the output shaft 326.
When the load applied to the pump 30 is smaller than the set value, that is, in the normal operation state of the pump 30, the rotation shaft 324 does not slip with respect to the output shaft 326, and the rotation shaft 324 is rotated along with the rotation of the output shaft 326. Rotated. On the other hand, when the load applied to the pump 30 reaches the set value, slip occurs, and the rotating shaft 324 is moved in the axial direction against the biasing force of the spring 346 by the effect of the slope. As shown in FIG. 10, when the output shaft 326 is rotated in the direction of the arrow P, the rotational shaft 324 is moved in the direction of the arrow S accordingly.

  As shown in FIG. 11, when the piston 304 faces the eccentricity gradually decreasing portion 318 of the eccentric cam 302 due to the movement of the eccentric cam 302 in the direction parallel to the axis L, the stroke of the reciprocating motion of the piston 304 is gradually decreased. It is done. A transmission driving force applied to the piston 304 via the eccentric cam 302 is reduced, and an increase in the discharge pressure of the pump 30 is suppressed. Although the piston 304 is reciprocated, the stroke is reduced, so that the hydraulic pressure in the pump chamber 84 is not sufficiently increased, and an increase in the discharge pressure is suppressed. When the stroke becomes equal to or less than a set value (for example, 0), the discharge of the hydraulic fluid from the pump chamber 84 is stopped. Further, if the stroke of the reciprocating motion of the piston 304 is reduced and the discharge pressure of the pump 30 is suppressed, the load applied to the electric motor 300 can be suppressed. Furthermore, since the hydraulic fluid is not allowed to flow out to the low pressure side through the relief valve, it is possible to prevent vibrations and noises from being generated due to the hydraulic fluid.

Further, when the load applied to the electric motor 300 is reduced, the urging force of the spring 346 allows the eccentric cam 302 to move in the direction opposite to the arrow S. The stroke of the piston 304 increases and the discharge pressure increases. The eccentric cam 302 is often returned to its original position.
In the present embodiment, the driving force transmission device 360 is configured by the eccentric cam 302, the engaging portion 328, and the like. A transmission driving force suppressing device 362 is configured by the engagement portion 328 and the portion of the driving force transmission device 360 that holds the bearing 344 movably in the axial direction with respect to the housing 340. The transmission driving force suppression device is also an axial movement allowance device. Further, the engaging portion 328 allows a difference in rotational speed between the output shaft 326 and the rotating shaft 324 and generates an axial force corresponding to the rotational speed difference. Therefore, the engaging portion 328 can be referred to as an axial rotation differential portion.
In the engaging portion 328, the rotating shaft 324 and the output shaft 326 can be engaged with each other by a pair of inclined surfaces.

Further, the pump device may be of the form shown in FIG. In the present embodiment, the output shaft 326 of the electric motor 300 is connected to the rotating shaft 324 of the eccentric cam 400 via the spline fitting portion 402. The spline fitting portion 402 engages the output shaft 326 and the rotation shaft 324 so as not to be relatively rotatable and to be relatively movable in a direction parallel to the axis L. The eccentric cam 400 includes an eccentric amount gradually changing portion 404 and an eccentric amount constant portion 406. The eccentric amount constant portion 406 has the smallest eccentric amount in the eccentric cam 400 and is provided on the side opposite to the spring 346 of the eccentric amount gradually changing portion 404.
In the present embodiment, the piston 304 is provided in a state of facing the eccentricity gradually changing portion 404 in a normal state.

When the hydraulic pressure in the discharge chamber is within the normal range, the eccentric cam 400 is rotated with the rotation of the electric motor 300, and a transmission driving force corresponding to the pump load is applied to the piston 304. .
The component in the S direction parallel to the axis L of the force in the direction crossing the axis L applied to the eccentric amount gradual change portion 404 of the eccentric cam 400 by the piston 304 is at an abnormal height. When it becomes larger, the eccentric cam 400 is moved in the arrow S direction. The eccentric amount of the portion where the piston 304 faces the eccentric cam 400 becomes small. Thereby, the stroke of the piston 304 is reduced, and the transmission driving force applied to the piston 304 is reduced. In this embodiment, the eccentric cam 302 is moved by a force in a direction parallel to the axis L applied to the eccentric cam 302 by the piston 304.

  The pump device according to the present invention can also be applied to a reflux type brake device that pumps up hydraulic fluid in a pressure reducing reservoir of a hydraulic brake device. Further, the present invention can be applied not only to a brake device but also to a vehicle suspension device, a power steering device, and the like. In addition to the above-described embodiments, the present invention can be carried out in various modifications and improvements based on the knowledge of those skilled in the art.

It is sectional drawing which shows the pump contained in the pump apparatus which is one Example of this invention. It is sectional drawing which shows the state which has a relief valve in the open state in the said pump. It is a figure which shows the brake circuit containing the said pump apparatus. It is sectional drawing which shows the pump contained in the pump apparatus which is another example of this invention. It is AA sectional drawing of the said pump. It is sectional drawing which shows the pump contained in the pump apparatus which is another one Example of this invention. It is sectional drawing which shows the state which has a relief valve in the open state in the said pump. It is a figure which shows notionally the pump apparatus which is another one Example of this invention. It is a figure which shows notionally the principal part of the engagement apparatus contained in the said pump apparatus. It is sectional drawing which shows the edge part of the piston of the pump contained in the said pump apparatus. It is a figure which shows the relationship between the moving amount | distance of the axial direction of an eccentric cam in the said pump apparatus, and the discharge pressure of a pump. It is a figure which shows notionally the pump apparatus which is another one Example of this invention.

Explanation of symbols

30 pump 80 piston 82 housing 130, 214 discharge side relief valve 132, 206 valve seat member 134, 212 valve seat 250 suction side relief valve 252 valve seat member 254 piston body 256 valve seat 300 electric motor 302, 400 eccentric cam 320, 322 , 406 Eccentricity constant part 318, 404 Eccentricity gradually changing part 328 Engaging part 346 Spring 360 Driving force transmission device 362 Axial movement allowance device 402 Spline fitting part

Claims (7)

A housing;
A piston fitted in the housing so as to be able to reciprocate;
A drive for reciprocating the piston;
A pump device that is provided between the piston and the drive device and includes a drive force transmission device that transmits the drive force of the drive device to the piston, and performs suction and discharge of the hydraulic fluid by reciprocating motion of the piston,
When the load applied to the pump device increases to a set value, the operation of the drive device is allowed and the transmission drive force, which is the drive force transmitted to the piston, is prevented from increasing beyond the set value. A pump device comprising a transmission driving force suppressing device.   The driving force transmission device includes a cam that is provided with an outer peripheral surface facing the piston and is rotated about one axis by the driving device, and the cam is separated from the axis at a position separated in the axial direction. The pump device according to claim 1, comprising a portion having a large distance to the cam surface and a portion having a small distance.   The pump device according to claim 2, wherein the cam has at least a portion where a distance from the axis to the cam surface gradually changes in the axial direction.   When the load of the pump device increases to a set value, the transmission driving force suppressing device has a direction parallel to the one axis of the cam in a direction in which the movement amount of the piston accompanying rotation of the cam decreases. The pump device according to claim 3, comprising an axial movement allowance device that allows movement.   The driving force transmission device includes: (a) an engagement device that engages an output shaft of the driving device with a rotating shaft of the cam; and (b) an output of the driving device that outputs the rotating shaft of the cam to the cam. The pump apparatus according to claim 4, further comprising an urging device that applies an urging force in a direction of pressing against the shaft.   The engagement device includes an engagement portion that engages the output shaft and the rotation shaft in a state that allows relative movement in a direction parallel to the one axis and prevents relative rotation, and moves in the axial direction. When the component in the direction parallel to one axis of the force in a direction crossing the one axis applied to the cam by the piston increases to a set value, the allowing device moves the cam in the direction parallel to the one axis. The pump device according to claim 5, which is allowed.   When the load of the pump device increases to a set value, the transmission driving force suppressing device has a direction parallel to the one axis of the cam in a direction in which the movement amount of the piston accompanying rotation of the cam decreases. An axial movement allowance device that allows movement, wherein the drive force transmission device is provided on (a) an output shaft of the drive device and a rotation shaft of the cam, respectively, with respect to a plane orthogonal to the one axis line An engagement device including an inclined surface and engaging the output shaft and the rotating shaft of the cam by engaging the inclined surfaces; and (b) driving the rotating shaft of the cam to the cam. An urging device that applies an urging force in a direction to be pressed against the output shaft of the device, wherein the driving force transmission device responds to relative rotation between the output shaft of the driving device and the rotating shaft of the cam. Is moved in a direction parallel to the one axis. Pump device according to claim 2 or 3 comprising a minute.

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