JP3278982B2 - pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump for sucking and discharging a fluid, and more particularly to a pump suitable for handling a fluid having a high kinematic viscosity.

[0002]

2. Description of the Related Art Conventionally, as a pump for controlling the supply of brake oil to a wheel cylinder in an anti-lock brake device, for example, a suction type in which a ball valve body 601 is urged by a compression spring 603 as shown in FIG. A piston pump 605 having a structure provided with a check valve is known. In this type of piston pump 605, it is difficult to inhale a fluid having a high kinematic viscosity, such as low-temperature brake oil, because the suction resistance of the suction check valve is large. As an improvement of this type of piston pump 605, FIG.
As illustrated in FIG. 2, the compression spring 705 is housed in the movable spring case 703 linked to the piston 701, thereby reducing the valve opening pressure of the suction check valve and changing the valve opening pressure depending on the piston stroke position. A pump 707 is known. However, even with this type of piston pump 707, it was difficult to suck in a fluid having a high kinematic viscosity such as low-temperature brake oil.

[0003] On the other hand, Japanese Patent Application Laid-Open No. 60-198382 discloses an outer peripheral groove 803 provided at the tip of a piston 801 and a ring-shaped externally fitted in the outer peripheral groove 803 as illustrated in FIG. A piston pump 807 having a structure that functions as a check valve for suction by changing a relative position of the seal member 805 in the axial direction is disclosed. The suction resistance of the suction check valve of this type of piston pump 807 is smaller than that of the suction check valve of the type in which the ball valve body is biased by a spring, and is excellent in this respect.

[0004]

However, FIG. 4 (b)
As shown in FIG.
The suctionable volume QA at 07 and 807 increases in the suction stroke from the top dead center to the bottom dead center of the piston, and decreases in the discharge stroke from the bottom dead center to the top dead center.

When the kinematic viscosity of the fluid is low, the fluid flows into the pump chambers 609, 709, 809 almost exactly following the increase in the suctionable volume QA during the suction stroke.
Although the suction volume of the piston pumps 605, 707, 807 is sufficient and the discharge is not insufficient, the fluid flows into the pump chambers 609, 709, 809 when the kinematic viscosity of the fluid becomes high, such as low-temperature brake oil. Since the speed is reduced, the inflow delay occurs without increasing the inhalable volume QA without the inflow amount QB of the fluid. As described above, when the piston passes the bottom dead center, the suctionable volume QA decreases.
Pump chambers 609, 7 for fluid per piston cycle
The final inflow amount QC into the tubes 09 and 809 is significantly lower than the maximum value Q0 (corresponding to bottom dead center) of the suctionable volume QA. In the example shown in FIG. 4B, the inflow amount QB of the fluid is Q0 /
This is a case where the gas flows only at (t4−t0) [cm ³ / sec], and the final flow amount QC [cm ³ ] per cycle is about 69% of the maximum value Q0 [cm ³ ]. That is, the volumetric efficiency of the pump is reduced to about 69%. Thus, the prior art piston pump 60
In 5,707 and 807, when the kinematic viscosity of the fluid is high, the volumetric efficiency is reduced, which is a problem.

[0006]

In order to solve this problem, the present invention employs the following means. That is, as illustrated in FIG. 1, the pump of the present invention includes a first pump chamber having a variable volume and a first pump chamber communicating with the first pump chamber.
A first suction port and a first discharge port, wherein a fluid is sucked from the first suction port and discharged from the first discharge port in accordance with increase or decrease in the volume of the first pump chamber. A first pump mechanism, a second pump chamber, a second suction port communicating with the second pump chamber, and a second suction port communicating with the second pump chamber and communicating with the first suction port. Discharge port,
A suction chamber is formed in the second pump chamber and formed on the second suction port side, and a discharge chamber is formed on the second discharge port side. When the second pump chamber is relatively movable along the axial direction with respect to the second pump chamber and relatively moves toward the discharge chamber, the communication between the suction chamber and the discharge chamber is cut off and the second pump chamber is moved toward the suction chamber. By providing a second pump mechanism provided with a valve means for communicating the suction chamber and the discharge chamber when moved, when the volume of the first pump chamber is increased, The valve means relatively moves to the discharge chamber side to draw fluid from the second suction port into the suction chamber, and also from the discharge chamber via the second discharge port and the first suction port. When the first pump chamber is filled with fluid and the volume of the first pump chamber decreases, It said valve means to flow the fluid into the discharge chamber from said suction chamber relative move to the suction chamber side while discharging the fluid from the first discharge port.

[0007]

In the pump having the above structure, the volume of the first pump chamber of the first pump mechanism is increased, and the valve means is relatively moved toward the discharge chamber in synchronization with the increase. As a result, in the second pump chamber, the volume of the suction chamber increases, and the volume of the discharge chamber decreases. However, since the communication between the suction chamber and the discharge chamber is interrupted by the valve means, the suction chamber is in a reduced pressure state. The discharge chamber is in a pressurized state. Therefore, the fluid is sucked into the suction chamber from the second suction port, and the fluid is discharged from the discharge chamber. Since the discharge chamber communicates with the first pump chamber via the second discharge port and the first suction port, the fluid discharged from the discharge chamber is filled in the first pump chamber (first pump chamber). Process).

Next, the volume of the first pump chamber is reduced, and in synchronization with this, the valve means relatively moves toward the suction chamber. As a result, the first pump chamber is in a pressurized state, and the fluid in the first pump chamber is discharged from the first discharge port. Further, in the second pump chamber, the volume of the suction chamber decreases and the volume of the discharge chamber increases. However, since the suction chamber and the discharge chamber are communicated by the valve means, the volume of the discharge chamber increases. Flows from the suction chamber to the discharge chamber (second stroke).

Further, the pump sequentially repeats the first and second strokes, sucks a fluid from the second suction port in accordance with an increase or a decrease in the volume of the first pump chamber, and pumps the second pump chamber and the first pump. The fluid is discharged from the first discharge port via the pump chamber.
As described above, the pump sucks the fluid in accordance with the increase in the volume of the second suction chamber in the first stroke. That is, the pump is capable of sucking a fluid having a volume corresponding to the increase in the volume of the suction chamber at the maximum. Therefore, the volume increase of the suction chamber is equal to the volume capable of sucking the fluid into the pump (hereinafter referred to as the volume).
(Referred to as inhalable volume).

[0010] The suctionable volume of the pump gradually increases in the first stroke, and becomes maximum at the end of the first stroke (start of the second stroke). In the second stroke, the volume of the suction chamber decreases in accordance with the movement of the valve means to the suction chamber side. On the back side of the valve means = discharge chamber side, the volume corresponds to the volume reduction of the suction chamber. To increase. At this time, since the suction chamber and the discharge chamber communicate with each other, the volume does not change in the entire second pump chamber. That is, the maximum pumpable volume of the pump at the end of the first stroke is held in the second pump chamber.

[0011] As described above, in the pump, the suctionable volume that has gradually increased in the first stroke and has reached the maximum is equal to the second suction volume.
Is maintained throughout the journey. For this reason, even in the following cases, the volumetric efficiency of the pump is less likely to decrease as compared with the related art. For example, when the kinematic viscosity of the fluid is high, a delay may occur in the inflow of the fluid with respect to the increase in the volume of the suction chamber in the first stroke. In this case, at the end of the first stroke, a decompression region where no fluid exists is formed in the suction chamber. This decompression region of the suction chamber is gradually eliminated by the movement of the valve means to the suction chamber in the next second stroke. However, according to the movement of the valve means, the rear side of the valve means = discharge chamber. A decompression region in which no fluid exists is newly formed. That is, the decompression region on the suction chamber side disappears with the movement of the valve means, and a corresponding decompression region is formed on the discharge chamber side. In the second stroke, the discharge chamber communicates with the second suction port through the suction chamber communicating with the discharge chamber, so that the fluid flows through the second chamber until the decompression region on the discharge chamber side is eliminated. From the suction port to the discharge chamber side. As described above, since the suction of the fluid is continued from the first stroke to the second stroke,
Even if the kinematic viscosity of the fluid is high, the efficiency of suction of the fluid into the pump is less likely to decrease than in the prior art. Therefore, even if the kinematic viscosity of the fluid is high, the volumetric efficiency of the pump does not easily decrease.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. (Embodiment 1) As shown in FIG.
The first cylinder member 10 constituting a part of the outer shell 102
4, a large-diameter hole 108 having one end communicating with the piston hole 106 and one end communicating with the piston hole 106 is coaxially formed. In the first cylinder member 104, a plurality of suction ports 110 communicating with the large-diameter hole 108 and opening to the outside are formed in the radial direction of the large-diameter hole 108.

In the large diameter hole 108, the first cylinder member 10
4, from the side of the fitting end 104 a to the vicinity of the suction port 110, a flange 112 a protruding near the center, a cylindrical fitting end 112 b adjacent to the flange 112 a, and a cone located on the opposite side to the fitting end 112 b. A fitting end 112b of the second cylinder member 112 having a trapezoidal truncated cone end 112c is fitted inside. The flange portion 112a of the second cylinder member 112 and the first cylinder member 1
A washer 114 is interposed between the fitting end 104a and the fitting end 104a. Further, inside the second cylinder member 112, the sliding hole 116 is substantially coaxial with the piston hole 106 of the first cylinder member 104 and communicates with the sliding hole 116 having the same diameter and opening on the fitting end 112 b side. Frustoconical end 112c
A discharge passage 120 that opens on the side is formed.

In the first cylinder member 104 and the second cylinder member 112, a first sliding portion 122 slidable in the piston hole 106 and a second sliding portion 124 slidable in the sliding hole 116 are provided. Is inserted so as to be able to reciprocate. Further, the first sliding portion 122 and the piston hole 10
An X-ring 118 for sealing is interposed between the X-rings 6 and 6. Inside the piston 126, a center hole 128 that opens at the end on the side of the sliding hole 116 and reaches near the first sliding portion 122.
Are drilled substantially coaxially with the piston 126. The piston 126 has a first sliding portion 122 of a center hole 128.
The four end communication holes 1 communicating with the center hole 128 near the closed end 130 on the side and opening to the outer peripheral surface 132 of the piston 126
34 along the radial direction of piston 126 about 9
It is drilled at an angle of 0 degrees. Further, the piston 126 is provided with an annular groove 136 between the end communication hole 134 and the second sliding portion 124.
Groove communication holes 144 for communicating the holes with the center hole 128
Are drilled at an angle of about 90 degrees with each other along the radial direction of the piston 126.

A rubber sliding ring 146 slidably inserted into the large-diameter hole 108 of the first cylinder member 104 is fitted in the groove 136 of the piston 126. The inner diameter of the sliding ring 146 is larger than the outer diameter of the bottom surface 138 of the groove 136, and
A gap 148 is formed between the two. The axial length of the sliding ring 146 is a pair of side walls 140 of the groove 136,
The distance between the sliding ring 146 and the groove 13
6, the sliding ring 14 located on the first sliding portion 122 side.
6 from the state in which the first end surface 150a abuts on the side wall 140 to the state in which the second end surface 150b of the slide ring 146 located on the second sliding portion 124 side abuts on the side wall 142. The relative position along can be changed. Further, when the piston 126 is moved in the direction of arrow L, the first end face 150a of the slide ring 146 is
40, and when the piston 126 is moved in the direction of arrow R, the second end face 150b of the sliding ring 146 is pressed by the side wall 142, and the sliding ring 146 is
6 can be moved in the same direction.

The sliding ring 146 is arranged so that the inside of the large-diameter hole 108 is connected to the discharge chamber 152 on the first end face 150a side and the second end face 150a.
and the suction chamber 154 on the b side, but the split state is not fixed, and the volumes of the discharge chamber 152 and the suction chamber 154 are changed by the sliding ring 1 accompanying the movement of the piston 126 described above.
It fluctuates according to the movement of 46. However, the sliding ring 14
6, when the first end face 150a is pressed by the side wall 140 (at the time of movement in the direction of the arrow L), the suction chamber 154 and the discharge chamber 152 communicate with each other through the groove communication hole 144, the center hole 128, and the end communication hole 134. Although the communication state is established, when the second end face 150b of the slide ring 146 is pressed by the side wall 142 (at the time of movement in the direction of the arrow R), the communication between the suction chamber 154 and the discharge chamber 152 is shut off.

Therefore, when the slide ring 146 moves in the direction of arrow R together with the piston 126, the suction chamber 154
Is decompressed, fluid can be sucked into the suction chamber 154 from the suction port 110, and the discharge chamber 152 is pressurized to the center hole 128 from the discharge chamber 152 through the end communication hole 134 and the groove communication hole 144. The fluid can be discharged to On the other hand, when the sliding ring 146 moves in the direction of the arrow L together with the piston 126, the volume of the suction chamber 154 decreases and the volume of the discharge chamber 152 increases.
4. Since the suction chamber 154 and the discharge chamber 152 communicate with each other through the center hole 128 and the end communication hole 134, the fluid can be moved from the suction chamber 154 to the discharge chamber 152. That is, the piston 126 and the sliding ring 146
And constitute valve means.

The piston 126 located in the sliding hole 116
The inner end 156 has a smaller outer diameter than the second sliding portion 124, and a step 158 is formed at a connection portion between the inner end 156 and the second sliding portion 124. This step 158 and the second
A compression spring 160 substantially coaxial with the piston 126 is interposed between the cylinder member 112 and biases the piston 126 in the direction of arrow R. In addition, a spherical valve seat 164 is provided at the opening of the center hole 128 on the inner end 156 side so that the ball valve body 162 can be in close contact with and contact with the ball valve body 162. The ball valve body 162 contacting the valve seat 164 and the second
A compression spring 166 substantially coaxial with the piston 126 is interposed between the cylinder member 112 and the compression spring 166 urges the ball valve body 162 in the direction of arrow R. Therefore, the ball valve 162 is seated on the valve seat 164, but the ball valve 1
When the force pressing the 62 exceeds the urging force of the compression spring 166, the ball valve body 162 separates from the valve seat 164.

On the other hand, the outer end face 168 of the piston 126 is in contact with an eccentric cam (not shown), and the rotation of the eccentric cam can drive the piston 126 in the direction of arrow L against the urging force of the compression spring 160. . Therefore, when the eccentric cam is rotated, the piston 126 is driven to reciprocate in the directions of the arrows R and L by the eccentric cam and the compression spring 160. When the ball valve body 162 is seated on the valve seat 164, the piston 126 also receives the urging force of the compression spring 166 via the ball valve body 162. It is driven in the direction of arrow L against the combined biasing force with the spring 166. The space in the sliding hole 116 whose volume increases or decreases according to the reciprocating motion of the piston 126 driven by the eccentric cam and the compression springs 160 and 166 is a pump chamber 170.
When the volume of the pump chamber 170 increases, fluid can be sucked into the pump chamber 170 from the center hole 128 side.

On the other hand, from the flange portion 112a of the second cylinder member 112 to the fitting end portion 10 of the first cylinder member 104
4a, a cylindrical spring storage hole 172, one end of which is closed, communicates with the spring storage hole 172,
A spring case 180 formed with a fitting hole 178 connected to the funnel-shaped portion 174 through a funnel-shaped portion 174 and a step 176 having a shape substantially aligned with the truncated cone end 112c of the cylinder member 112 and having the other end opened. A gap 182 is held between the funnel-shaped part 174 and the truncated cone end 112c so as to be fitted outside. The end 184 of the spring case 180 on the side of the fitting hole 178 is swaged along the direction of reducing the diameter. Due to the caulking and the step 176, the fitting end portion 104a of the first cylinder member 104, the washer 114, and the flange portion 112a of the second cylinder member 112 are in fluid-tight contact with each other.
04, the second cylinder member 112 and the spring case 180 are integrally connected, and the first cylinder member 104 and the spring case 180 form the outer shell 102.

A spherical valve seat 188 is provided in the opening of the discharge passage 120 formed in the second cylinder member 112 so that the ball valve element 186 can come into close contact with and contact with the ball valve element 186.
A compression spring 190 inserted into the spring receiving hole 172 substantially coaxially with the discharge passage 120 is interposed between the ball valve element 186 abutting on the valve seat 188 and the spring case 180. Urges the ball valve element 186 in the direction of arrow R. Therefore, the ball valve element 186 is in a state of being seated on the valve seat 188. However, when the force pressing the ball valve element 186 from the discharge passage 120 side exceeds the urging force of the compression spring 190, the ball valve element 186 is not actuated. Detach from seat 188. Further, a pair of discharge ports 192 communicating with the gap 182 and opening on the outer surface of the spring case 180 are formed in the spring case 180.
Are formed at positions facing each other along the diameter direction of the spring case 180. Therefore, the piston 1
When 26 moves in the direction of reducing the volume of the pump chamber 170, the fluid in the pump chamber 170 is pressurized to lift the ball valve body 186, and the fluid can be discharged from the pump chamber 170 to the discharge port 192. It is.

Note that the casing and the pump 100 are
O-ring 1 externally fitted to the end of the cylinder member 104
96, an end face 197 that is in close contact with the casing, and O fitted around the center of the spring case 180.
The ring 194 is liquid-tightly attached to the portion,
A space formed between the casing at the portion corresponding to the portion between the O-ring 196 and the end surface 197 and the pump 100 is defined as a suction path (second suction port), and A space formed between the pump 100 and the pump 100 is a discharge path (first discharge port).

Next, the operation of the pump 100 will be described with reference to FIGS. In FIG. 3, the part numbers of the main parts are shown in FIG.
In (d), the illustration of the part numbers is omitted. (First Stroke) First, FIG. 3A shows a state of the pump 100 when the piston 126 reaches the top dead center. In this state, the volume of the pump chamber 170 is the minimum, which corresponds to a state in which the discharge of the fluid from the pump chamber 170 to the discharge port 192 side is completed. Further, the sliding ring 146 has the first end face 150a in contact with the side wall 140 of the groove 136, and the suction chamber 154 and the discharge chamber 152 communicate with each other.

Next, the piston 126 receiving the urging force of the compression spring 160 moves according to the rotation of the eccentric cam.
It moves toward the bottom dead center from the position shown in FIG. 3A (hereinafter, the movement in this direction is referred to as descending). This piston 12
6, the volume of the pump chamber 170 increases, and the pump chamber 170 is in a reduced pressure state.

FIG. 3B shows that the piston 126 is
6 shows a state in which the side wall 142 of the groove 136 is brought into contact with the second end face 150b of the sliding ring 146 by descending from the top dead center by a distance corresponding to the difference in the axial length between the sliding ring 6 and the sliding ring 146. . In this state, the side wall 142 and the second end surface 150b
Thus, communication between the suction chamber 154 and the discharge chamber 152 is interrupted, and the discharge chamber 152 communicates only with the center hole 128 side.

Further, the piston 126 continues to descend from the state shown in FIG. 3B to the bottom dead center (see FIG. 3C). When the piston 126 descends, the sliding ring 146 is pressed via the side wall 142 of the groove 136 and moves in the same direction as the piston 126. The volume of the suction chamber 154 increases in accordance with the movement of the sliding ring 146, and the suction chamber 154 is reduced in pressure. Therefore, the fluid is sucked from the suction port 110 into the suction chamber 154 according to the increase in the volume of the suction port 154. . At the same time, the volume of the discharge chamber 152 is reduced to be in a pressurized state, so that the fluid is discharged from the discharge chamber 152 to the center hole 128 through the end communication hole 134 and the groove communication hole 144. The fluid discharged to the center hole 128 side lifts the ball valve body 162 against the urging force of the compression spring 166 and flows into the pump chamber 170.

As described above, in the first stroke, the suction port 11
The suction of the fluid from 0 to the suction chamber 154, the discharge of the fluid from the discharge chamber 152 to the center hole 128 side, and the filling of the pump chamber 170 with the fluid are performed in parallel. (Second stroke) The piston 126 that has reached the bottom dead center subsequently moves in the direction of the top dead center (hereinafter, movement in this direction is ascending).

FIG. 3D shows that the piston 126 is
6 shows a state in which the side wall 140 of the groove 136 is in contact with the first end surface 150a of the sliding ring 146 by ascending from the bottom dead center by a distance corresponding to the difference in axial length between the sliding ring 146 and the sliding ring 146. . In this state, the suction chamber 154 and the discharge chamber 152 communicate with each other via the groove communication hole 144, the center hole 128, and the end communication hole 134.

Further, the piston 126 keeps rising from the state shown in FIG. 3D to the top dead center (see FIG. 3A). When the piston 126 rises, the sliding ring 146 is pressed through the side wall 140 of the groove 136 and moves in the same direction as the piston 126. In response to the movement of the sliding ring 146, the volume of the suction chamber 154 decreases, and the volume of the discharge chamber 152 increases. Suction chamber 154 and discharge chamber 1
Since the communication is established between the discharge chamber 152 and the discharge chamber 152, the fluid corresponding to the increase in the volume of the discharge chamber 152 flows from the suction chamber 154 to the discharge chamber 152.

The volume of the pump chamber 170 decreases in accordance with the rise of the piston 126. However, since the discharge of the fluid from the discharge chamber 152 is stopped, the pressing force for lifting the ball valve body 162 disappears. The ball valve element 162 is a valve seat 16
Sit at 4. Therefore, the communication between the center hole 128 and the pump chamber 170 is interrupted, and the inside of the pump chamber 170 is pressurized according to the decrease in the volume. For this reason, the fluid in the pump chamber 170 whose pressure has increased is compressed by the compression spring 1.
The ball valve body 186 is lifted against the urging force of 90,
It flows out of the pump chamber 170 and is discharged from the discharge port 192.

As described above, in the second stroke, the suction chamber 15
4 to the discharge chamber 152 and the pump chamber 17
The discharge of the fluid from 0 to the discharge port 192 is performed in parallel. Further, the pump 100 sequentially repeats the first and second strokes, sucks fluid from the suction port 110, and discharges fluid from the discharge port 192.

As described above, the pump 100 sucks the fluid in accordance with the increase in the volume of the suction chamber 154 in the first stroke. That is, the pump 100 is capable of sucking a fluid having a volume corresponding to the increase in the volume of the suction chamber 154 at the maximum. Therefore, the increase in the volume of the suction chamber 154 becomes a volume (hereinafter, referred to as a suctionable volume) QA that can suck the fluid into the pump 100.

As shown in FIG. 4A, the suctionable volume QA of the pump 100 is changed from the time (t ₁ ) corresponding to FIG. 3B to the time corresponding to FIG. It gradually increases to (t ₂ ), and reaches the maximum value Q 0 of the suctionable volume QA at the bottom dead center (t ₂ ) of the piston 126.

When the piston 126 passes the bottom dead center and enters the second stroke, the volume of the suction chamber 154 decreases in accordance with the movement of the sliding ring 146 toward the suction chamber 154, and the sliding ring 1
On the back side of 46 = the discharge chamber 152 side, the volume increases corresponding to the volume reduction of the suction chamber 154.

As described above, in this second stroke, since the ball valve body 162 is seated on the valve seat 164, the space extending from the suction port 110 to the center hole 128 is equal to the suction port 110.
No communication with other parts. The suction chamber 154 and the discharge chamber 152 communicate with each other.

Therefore, the center hole 12 is
In the space up to 8, the sliding ring 146 is interposed
The volume on the chamber 154 side decreases and the volume on the discharge chamber 152 side increases
However, the volume does not increase or decrease in the entire space. You
That is, the maximum value Q0 at the bottom dead center of the piston 126 is
The pumpable suction volume QA of the pump 100
It can be held in the space from 0 to the center hole 128.
Becomes (t_Two~ T_Three~ T _Four~ T_Five).

As described above, in the pump 100, the suctionable volume QA which gradually increases in the first stroke and reaches the maximum value Q0 when the piston 126 reaches the bottom dead center (t ₂ ).
At the time when the communication between the suction chamber 154 and the discharge chamber 152 is cut off in the next cycle through the second stroke (t ₅ , FIG.
(B)) is held. Therefore, even in the case as shown in FIG. 4A, the volumetric efficiency of the pump 100 does not decrease.

For example, when the kinematic viscosity of the fluid is high, a delay may occur in the inflow of the fluid with respect to the increase in the volume of the suction chamber 154 in the first stroke. In this case, at the end of the first stroke, a decompression region where no fluid exists is formed in the suction chamber 154. The decompression region of the suction chamber 154 corresponds to the suction chamber 154 of the sliding ring 146 in the next second stroke.
The movement of the sliding ring 146 gradually eliminates the pressure. However, in accordance with the movement of the sliding ring 146, a decompression region in which no fluid is newly present in the discharge chamber 152 behind the sliding ring 146 is formed. That is, as the sliding ring 146 moves, the decompression region on the suction chamber 154 side disappears, and a corresponding decompression region is formed on the discharge chamber 152 side. In the second stroke, the discharge chamber 152 is connected to the suction chamber 154 communicating therewith.
Fluid communicates with the suction port 110 through the suction port 11 until the pressure reduction region on the discharge chamber 152 side is eliminated.
The flow from 0 to the discharge chamber 152 side is continued. FIG. 4 (a)
FIG. 3 illustrates a change with time of the inflow amount QB of the fluid into the pump 100. FIG. The flow rate QB [cm ³ ] of the fluid is Q 0 / (t ₅ −t ₁ )
_{= Q0 / (t 4 -t 0} ) Even if you do not come to flow only in the inflow rate of [cm ³ / sec], the final flow rate per cycle Q
C can reach the maximum value Q0, and the volumetric efficiency of the pump 100 does not decrease. On the other hand, in the prior art, FIG.
(B), the fluid is the same inflow speed (Q0 / (t ₄
−t ₀ ) [cm ³ / sec]) Even if it flows in, the inhalable volume QA
, The final inflow amount QC can reach only about 69% of the maximum value Q0, and the volumetric efficiency of the pump decreases.

As described above, in the present invention, since the suction of the fluid is continued from the first stroke to the second stroke, even if the kinematic viscosity of the fluid is high, the pump 100
The suction efficiency of the fluid into the pump is less likely to decrease than in the prior art.
Therefore, even if the kinematic viscosity of the fluid is high, the volume efficiency of the pump 100 is not easily reduced. (Experiment) The pump 100 of the first embodiment and the conventional piston pump 707 shown in FIG. 12 are connected to each other in a circuit provided with a reservoir tank T, a relief valve R and a flow meter F as shown in FIG. Brake oil at a temperature of about -30 ° C (Kinematic viscosity of about 350 × 10 ^-6 [m ² / sec])
A flow measurement experiment using was performed. The geometric displacement flow rates of the pump 100 and the piston pump 707 used in the experiment were both 4.58 [cm ³ / sec].
It is. Table 1 shows the experimental results. FIG. 5B is a graph of the experimental result.

[0040]

[Table 1]

As is clear from Table 1, the pump 100 of the first embodiment has a small decrease in volumetric efficiency even for a fluid having a high kinematic viscosity, and has a better suction and discharge capability than the conventional piston pump. You can see that. Here, the geometric fluid movement amount of the pump 100 of the first embodiment is determined.
An example of determining three dimensions will be described.

The five dimensions are d ₁ , d ₂ ,
d ₃ , l, l _s , and these dimensions determine the geometric fluid movement amounts Q ₁ , Q ₂ , Q ₃ [cm ³ ] shown in Table 2. d ₁ [cm]; sliding hole 116 of second cylinder member 112
Inner diameter (diameter dimension) d ₂ [cm]; large-diameter hole 108 of first cylinder member 104
Inner diameter (diameter dimension) d ₃ [cm]; piston hole 1 of first cylinder member 104
06 inner diameter (diameter dimension) l [cm]; stroke length from top dead center to bottom dead center of piston 126 l _s [cm]; axis between a pair of side walls 140, 142 of annular groove 136 of piston 126 Difference between the axial length l ₁ and the axial length l ₂ of the sliding ring 146 (l ₁ −l ₂ )

[0043]

[Table 2]

First, Q ₁ is determined from d ₁ , d ₂ , d ₃ , l, l _{s according} to the required performance and specifications of the pump.
D ₁ and l are set so as to satisfy the expression for Q ₁ in Table 2 above. The remaining d _2, d _3, l _s various settings for are possible, should indicate the setting example shown in Table 3.

[0045]

[Table 3]

As an effect of the setting examples 2, 5, and 8 in which Q ₂ > Q ₁ , the time from when the piston 126 passes the bottom dead center to when the pressure in the pump chamber 170 rises becomes shorter,
Since the volume efficiency of the pump 100 is improved and the pressure in the pump chamber 170 increases at the time when the moving speed of the piston 126 is low, there is an effect of reducing vibration and noise generated from the pump 100. The amount (Q ₂ -Q ₁ ) of the pump chamber 170 that is to be charged extra is determined by the method of absorbing the elastic deformation of the sliding ring 146 or the method of using the sliding ring 1.
There is a method of leaking from the outer peripheral portion of 46 and the side wall 142. In addition, in the setting examples 3, 6, and 9 in which Q ₂ <Q ₁ , the pump chamber 170 is not filled excessively, so that the amount of elastic deformation of the sliding ring 146 is reduced. This has the effect of lengthening the years. (Embodiment 2) As shown in FIG.
Reference numeral 00 denotes an example in which the piston 226 is constituted by a first piston member 226a on the pump chamber 170 side and a second piston member 226b on the drive end side by an eccentric cam. Since other configurations are the same as those of the first embodiment, the same parts as those of the first embodiment are denoted by the same part numbers, and detailed description is omitted. The operation of the pump 200 is the same as that of the first embodiment, and the effect thereof is also the same.

However, since the piston 226 is composed of the first piston member 226a and the second piston member 226b, the sliding ring 14
When the piston 226 is made to penetrate through the second piston member 226, for example, a sliding ring 146 is fitted over the second piston member 226 b, and then the first piston member 226 a and the second piston member 226 b can be connected. Therefore, when the piston 226 is passed through the sliding ring 146, the sliding ring 146 does not need to be elastically deformed, so that the probability of damage to the sliding ring 146 during assembly is reduced,
The yield is improved.

As shown in FIG. 7, the pump 250 of this embodiment can be assembled even if an inelastic material is used as the sliding ring, so that the sliding of the inelastic ring 252 and the O-ring 253 is combined. The use of the moving ring 251 can extend the service life. The sliding ring 2
Structures other than 51 are the same as those in FIG. 6, and the operation and effect are the same as those in the first embodiment. (Embodiment 3) As shown in FIGS. 8 and 9, a pump 300 of this embodiment is an example in which a cylinder 304 is integrated, and an outer periphery of the cylinder 304 is cut off in a half-moon shape to form a suction port 310. Since other configurations are the same as those of the first embodiment, the same parts as those of the first embodiment are denoted by the same part numbers, and detailed description is omitted. The operation of the pump 300 is the same as that of the first embodiment, and the effect thereof is also the same.

However, since the suction port 310 has the above shape, when assembling the pump 300, first, the slide ring 146 is inserted into the large-diameter hole 108 from the suction port 310 along the arrow X direction. Thereafter, the piston 126 is inserted from the piston hole 106, and is inserted into the slide hole 116 while increasing the inner diameter of the slide ring 146, so that the state shown in FIG. When the cylinder 304 is constituted by one part as described above,
The accuracy of the coaxiality between the sliding hole 116 of the cylinder 304 and the piston hole 106 can be improved, and the discharge performance can be improved and the service life can be extended. (Embodiment 4) This embodiment is different from Embodiments 1 to 3 in that a suction chamber is provided on the outer surface side of the cylinder.

As shown in FIG. 10, a suction passage 404 for sucking a fluid is provided in a casing 402 of the pump 400.
And a discharge path 406 for discharging.
A cylinder 408 and a spring case 410 are housed substantially coaxially in the casing 402. The cylinder 408 and the spring case 410 are caulked at a caulking portion 412 of the spring case 410 and are fixed to each other. Further, a ring groove 416 provided on the outer end 414 of the cylinder 408 on the side remote from the caulking portion 412 and the caulking portion 4 of the spring case 410
O-rings 420 and 422 are respectively mounted in ring grooves 418 provided on the side remote from 12, and a region defined by the O-rings 420 and 422 and the casing 402 is liquid-tight to the outside. .

A relatively large-diameter flange portion 424 is provided near the caulking portion 412 of the cylinder 408. A relatively small outside diameter portion 426 is provided between the flange portion 424 and the outside end portion 414, and a suction passage is provided between the small outside diameter portion 426 and the inner wall 428 of the casing 402. An annular space 430 communicating with 404 is formed. On the other hand, inside the cylinder 408, an outer end 414 is provided.
A piston hole 432 opening at one end and one end of the piston hole 432
And a discharge passage 434 whose other end is open is formed substantially coaxially with the piston hole 432 and the discharge passage 43.
A step portion 436 is formed in a portion communicating with the portion 4. The small outer diameter portion 426 of the cylinder 408 has a piston hole 4
A pair of long diameter holes 438 having a long diameter along the axial direction of 32 and communicating the piston hole 432 and the annular space 430 are formed so as to face each other along the diameter direction of the cylinder 408.

In the piston hole 432 of the cylinder 408,
A piston 444 having a first sliding portion 440 located near the outer end portion 414 and a second sliding portion 442 located near the center of the piston hole 432 is connected to the first sliding portion 440 and the second sliding portion 442. , The piston hole 432 is slidably inserted, and an X ring 446 for sealing is mounted in a ring groove 440 a provided in the first sliding portion 440. An annular outer circumferential groove 448 is formed between the first sliding portion 440 and the second sliding portion 442 of the piston 444 along the outer circumferential direction of the piston 444. Further, in the piston 444, a center hole 450 which is opened at an end in the piston hole 432 and reaches near the center of the piston 444 is formed substantially coaxially with the piston 444.
50 and four communicating holes 45 opening in the outer peripheral groove 448.
2 are approximately 90 apart from each other along the radial direction of the piston 444.
Drilled at an angle of degree. On the other hand, the piston 44
4, a connecting rod 45 commonly passing through a pair of communicating holes 452 opposed to each other with the center hole 450 and the center hole 450 interposed therebetween.
4 is attached. Both ends 456 of this connecting rod 454
a and 456b further have a long hole 438 of the cylinder 408.
Through the annular space 430 between the cylinder 408 and the casing 402, and can reciprocate with the piston 444 along the axial direction of the piston 444.
However, the reciprocating motion of the connecting rod 454 is restricted by the long diameter of the long hole 438, and the stroke of the piston 444 is similarly restricted. In the annular space 430, a cylindrical member 460 having a ring storage groove 458 at the center and externally fitting to the small outer diameter portion 426 of the cylinder 408 is provided.
8 and outer surface 426 of small outer diameter portion 426 of cylinder 408
a is slidably accommodated. This cylindrical member 460
The connecting end 462 adjacent to the arrow R side of the ring storage groove 458 is connected to the ends 456a and 456b of the connecting rod 454, and can reciprocate in the annular space 430 according to the reciprocating motion of the piston 444. It is. The cylindrical member 460 has an inner / outer communication hole 464 for communicating the ring housing groove 458 with the inside of the cylindrical member 460.
8 can communicate with the long diameter hole 438 of the cylinder 408 via the inner and outer communication holes 464. The communication end 466 adjacent to the ring storage groove 458 on the opposite side to the connection end 462 is provided with a plurality of communication grooves 470 having an inclined bottom surface 468 whose depth increases as the distance from the ring storage groove 458 increases. The communication groove 470 and the casing 40
A communication passage 472 is formed between the inner wall 428 and the second inner wall 428. Further, the casing 40 is provided in the ring accommodation groove 458.
A sliding ring 474 slidable on the second inner wall 428 is fitted outside. The axial length of the sliding ring 474 is slightly shorter than the width of the ring receiving groove 458, and the axial length of the sliding ring 474 is smaller than the width of the ring receiving groove 458 (= the cylindrical member 460). The position can be changed, and when the cylindrical member 460 is driven by the piston 444 to reciprocate, the side wall 458a, 4
58b, it can be moved in the same direction as the cylindrical member 460. The small outer diameter portion 426 of the cylinder 408
Is provided with a sealing ring 476.

With the above structure, the cylindrical member 460 and the sliding ring 474 are formed by the annular space 430 and the long hole 43.
8, a series of spaces formed by the outer circumferential groove 448, the communication hole 452, and the center hole 450 are divided into two parts, the suction path 404 side and the center hole 452 side, and a suction chamber 478 is formed on the suction path 404 side. A discharge chamber 480 is formed on the center hole 450 side. However, the divided state is not fixed, and the volumes of the suction chamber 478 and the discharge chamber 480 change in accordance with the movement of the cylindrical member 460 and the sliding ring 474 accompanying the movement of the piston 444. Also, the cylindrical member 460
When the sliding ring 474 is pressed by the side wall 458a (at the time of the movement in the direction of the arrow L) with the movement of the suction chamber 478, the suction chamber 478 and the discharge chamber 480 communicate with the communication path 472, the ring storage groove 458, and the inner and outer communication holes 464. However, when the sliding ring 474 is pressed by the side wall 458b (movement in the direction of arrow R), the communication between the suction chamber 478 and the discharge chamber 480 is shut off.

Accordingly, when the cylindrical member 460 and the sliding ring 474 are driven by the piston 444 to move in the direction of the arrow R, the volume of the suction chamber 478 increases and the pressure in the suction chamber 478 is reduced, and the volume of the discharge chamber 480 decreases. Then, it becomes a pressurized state.
Therefore, in this case, the fluid can be sucked into the suction chamber 478 from the suction passage 404, and the fluid can be discharged from the discharge chamber 480. On the other hand, when the cylindrical member 460 and the slide ring 474 move in the direction of the arrow L, the suction chamber 478
The volume of the discharge chamber 480 increases and the volume of the discharge chamber 480 increases. However, since the suction chamber 478 and the discharge chamber 480 communicate as described above, it is possible to move the fluid from the suction chamber 478 to the discharge chamber 480. it can.

The piston 4 located in the piston hole 432
The inner end 444a of the 44 has a smaller outer diameter than the second sliding portion 442, and a step 482 is formed at a connection portion between the inner end 444a and the second sliding portion 442. This step 48
2 and a step 436 of the cylinder 408 facing the compression spring 484 substantially coaxial with the piston 444.
, And urges the piston 444 in the direction of arrow R. Further, a spherical valve seat 488 to which a ball valve body 486 can be in close contact and abuts is provided at the opening of the center hole 450 on the inner end portion 444a side. A compression spring 490 substantially coaxial with the piston 444 is interposed between the ball valve element 486 abutting on the valve seat 488 and the cylinder 408. The compression spring 490 attaches the ball valve element 486 in the direction of arrow R. I'm going. For this reason, the ball valve element 486
Is in a state of being seated on the valve seat 488, but the force pressing the ball valve body 486 from the center hole 450 side is
If the urging force exceeds 90, the ball valve element 486 lifts from the valve seat 488.

On the other hand, the outer end surface 453 of the piston 444 is in contact with an eccentric cam (not shown), and the rotation of the eccentric cam can drive the piston 444 in the direction of arrow L against the urging force of the compression spring 484. . Therefore, when the eccentric cam is rotated, the piston 444 is reciprocally driven in the directions of the arrows R and L by the eccentric cam and the compression spring 484. When the ball valve element 486 is seated on the valve seat 488, the piston 444 also receives the urging force of the compression spring 490 via the ball valve element 486. In this case, the piston 444 compresses with the compression spring 484. It is driven in the direction of the arrow L against the combined biasing force with the spring 490. The space in the piston hole 432 whose volume increases or decreases according to the reciprocating motion of the piston 444 driven by the eccentric cam and the compression springs 484 and 490 is the pump chamber 4.
When the capacity of the pump chamber 492 increases, the fluid can be sucked into the pump chamber 492 from the center hole 450 side.

On the other hand, the cylinder 4
08 inside the spring case 410
Ball chamber 4 communicating with discharge passage 434 of cylinder 408
A cylindrical spring housing hole 496 communicating with the ball chamber 94 and the ball chamber 494 and having the other end closed is formed substantially coaxially with the discharge passage 434. Also, the spring case 41
In the case 0, the spring case 41 communicates with the ball chamber 494.
A pair of discharge ports 498 opening on the outer surface 410a of the spring case 410 are formed at positions facing each other along the diametrical direction of the spring case 410. The pair of discharge ports 498 are provided on the outer surface 410a of the spring case 410, the O-ring 422,
Flange 424 of cylinder 408 and casing 4
02 communicates with the discharge passage 406 through an annular space 500 formed by the same. Further, the cylinder 408
The opening of the discharge passage 434 formed in the
Is provided with a spherical valve seat 504 to which the ball valve body 502 housed in the container can closely contact and abut. The ball valve body 502 is urged in the direction of arrow R by a compression spring 506 inserted into the spring housing hole 496 substantially coaxially with the discharge passage 434. Therefore, the ball valve body 50
2 is in a state of being seated on the valve seat 504,
When the force pressing the ball valve 502 from the fourth side exceeds the urging force of the compression spring 506, the ball valve 502 is lifted from the valve seat 504. With such a configuration,
When the piston 444 moves in the direction to decrease the volume of the pump chamber 492, the fluid in the pump chamber 492 is pressurized to lift the ball valve body 502, and the pump chamber 492 is lifted.
The fluid can be discharged from No. 2 to the discharge path 406 via the discharge port 498.

Next, the operation of the pump 400 will be described. The operation principle of the pump 400 of this embodiment and the operation principle of the pumps 100 to 300 of the first to third embodiments are as follows.
Since the operation is almost the same, FIG. 3 used for describing the operation of the pump 100 according to the first embodiment is referred to for reference. (First stroke) First, when the piston 444 is at the top dead center (corresponding to FIG. 3A), the volume of the pump chamber 492 is minimum, and the fluid is discharged from the pump chamber 492 to the discharge path 406 side. Is completed. The sliding ring 47
Reference numeral 4 contacts the side wall 458a of the ring storage groove 458, and the suction chamber 478 and the discharge chamber 480 communicate with each other.

Next, the piston 444 receiving the urging force of the compression spring 484 moves according to the rotation of the eccentric cam.
It descends toward the bottom dead center. As the piston 444 descends, the volume of the pump chamber 492 increases, and the pump chamber 492 is in a reduced pressure state. Further, the cylindrical member 460 connected to the piston 444 via the connecting rod 454 is
44, the side wall 458b of the ring storage groove 458 is moved to the bottom dead center side by a distance corresponding to the axial length difference between the ring storage groove 458 and the slide ring 474.
74 and the communication between the suction chamber 478 and the discharge chamber 480 is cut off (corresponding to FIG. 3B).

Further, the piston 444 continues to descend until it reaches the bottom dead center, and the cylindrical member 460 moves accordingly. As a result, the sliding ring 474 is
58 through the side wall 458 b of the cylindrical member 46.
Moves with 0. Since the volume of the suction chamber 478 increases in accordance with the movement of the cylindrical member 460 and the pressure in the suction chamber 478 is reduced, the fluid is sucked from the suction passage 404 into the suction chamber 478 in accordance with the increase in the volume of the suction chamber 478. In addition, the discharge chamber 48
Since the volume of the discharge chamber 480 is reduced to be in a pressurized state, the fluid in the discharge chamber 480 lifts the ball valve body 486 against the urging force of the compression spring 490 and flows into the pump chamber 492 (FIG. 3 (b)). ) To FIG. 3 (c)).

As described above, in the first stroke, the suction path 40
4 to the suction chamber 478, discharge of the fluid from the discharge chamber 480, and filling of the pump chamber 492 with the fluid are performed in parallel. (Second stroke) The piston 444 that has reached the bottom dead center subsequently rises in the direction of the top dead center. When the piston 444 and the cylindrical member 460 rise from the bottom dead center by a distance corresponding to the difference in the axial length between the ring storage groove 458 and the slide ring 474, the side wall 458a of the ring storage groove 458 is attached to the slide ring 474. Contact (corresponding to FIG. 3D). In this state, the suction chamber 478 and the discharge chamber 480 are connected to the communication passage 472,
They communicate with each other through the ring storage groove 458 and the inner and outer communication holes 464.

Further, the piston 444 continues to move up to the top dead center (corresponding to FIGS. 3D to 3A). In response to the rise of the piston 444, the cylindrical member 460
It moves in the same direction as the piston 444. The sliding ring 474 is also pressed via the side wall 458a of the ring storage groove 458, and moves together with the cylindrical member 460. The volume of the suction chamber 478 decreases in accordance with the movement of the cylindrical member 460,
The volume of the discharge chamber 480 increases. Since the suction chamber 478 and the discharge chamber 480 communicate with each other, a fluid corresponding to the volume increase of the discharge chamber 480 flows from the suction chamber 478 to the discharge chamber 480.

The volume of the pump chamber 492 is reduced in accordance with the rise of the piston 444. However, since the discharge of the fluid from the discharge chamber 480 is stopped, the pressing force for lifting the ball valve element 486 disappears. The ball valve element 486 is a valve seat 48
Sit at 8. Therefore, communication between the center hole 450 and the pump chamber 492 is cut off, and the inside of the pump chamber 492 is pressurized according to the decrease in the volume. For this reason, the fluid in the pump chamber 492 whose pressure has increased is compressed by the compression spring 5.
The ball valve body 502 is lifted against the urging force of 06,
The discharge path 4 flows out of the pump chamber 492 through the discharge port 498.
Discharge from 06.

As described above, in the second stroke, the suction chamber 47
8 into the discharge chamber 480 and the pump chamber 49
The discharge of the fluid from 2 to the discharge path 406 is performed in parallel. Further, the pump 400 sequentially repeats the first and second strokes, sucks the fluid from the suction passage 404 and discharges the fluid from the discharge passage 406.

As described above, the pump 400 sucks the fluid in accordance with the increase in the volume of the suction chamber 478 in the first stroke. That is, the pump 400 is capable of sucking a fluid having a volume corresponding to the volume increase of the suction chamber 478 at the maximum, and the volume increase of the suction chamber 478 becomes the suctionable volume QA of the pump 400.

As shown in FIG. 4A, the suctionable volume QA of the pump 400 is changed from the time (t ₁ ) corresponding to FIG. 3B in the first stroke to the time corresponding to FIG. It gradually increases to (t ₂ ) and reaches the maximum value Q 0 at the bottom dead center (t ₂ ) of the piston 444. When the piston 444 passes the bottom dead center and enters the second stroke, the volume of the suction chamber 478 decreases in accordance with the movement of the cylindrical member 460 toward the suction chamber 478, and the rear side of the cylindrical member 460 = the discharge chamber 480 side. Then
The volume increases corresponding to the volume reduction of the suction chamber 478.

As described above, in the second stroke, since the ball valve element 486 is seated on the valve seat 488, the space from the suction passage 404 to the center hole 450 is in a communicating state, and the other parts of the pump 400 Not in communication with Therefore, in the space from the suction passage 404 to the center hole 450,
With the cylindrical member 460 interposed, the volume on the suction chamber 478 side decreases and the volume on the discharge chamber 480 side increases, but the volume does not increase or decrease in the entire space. That is, the piston 444
Inhalable volume QA of the pump 400 becomes the maximum value Q0 at bottom dead center of the will be kept at the maximum value Q0 in the space leading to the central hole 450 from the suction passage 404 (t ₂ ~t ₃ ~t ₄ ~t _5).

As described above, in the pump 400, the suctionable volume QA which gradually increases in the first stroke and reaches the maximum value Q0 when the piston 444 reaches the bottom dead center (t ₂ ).
At the time when the communication between the suction chamber 478 and the discharge chamber 480 is cut off in the next cycle through the second stroke (t ₅ , FIG.
(Corresponding to (b)) is held at the maximum value Q0. Therefore, similar to the pumps 100 to 300 of the first to third embodiments, the suction of the fluid is continued from the first stroke to the second stroke, so that even if the kinematic viscosity of the fluid is high, the pump 400 The fluid suction efficiency is less likely to decrease than in the prior art. Therefore, even if the kinematic viscosity of the fluid is high, the pump 40
The volumetric efficiency of 0 is not easily reduced.

The pump of the present invention has been described according to the first to fourth embodiments. However, the present invention is not limited to these embodiments, and can be implemented in various ways without departing from the gist of the present invention.

[0070]

As described above, the pump according to the present invention can maintain the suctionable volume QA without lowering even after passing the bottom dead center unlike the prior art (see FIGS. 4 (a) and 4 (b)). ), The volumetric efficiency of the pump does not easily decrease even if the kinematic viscosity of the viscous fluid is high.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating the configuration of a pump according to the present invention.

FIG. 2 is a cross-sectional view of the pump according to the first embodiment.

3A and 3B are explanatory diagrams of the operation of the pump according to the first embodiment. FIG. 3A shows a state where the piston is at the top dead center, FIG. 3B shows a state where the piston is slightly lowered from the top dead center, FIG.
3C illustrates a state where the piston is at the bottom dead center, and FIG. 3D illustrates a state where the piston slightly rises from the bottom dead center.

FIG. 4 is a graph showing a change in the suctionable volume of the pump according to the embodiment and the conventional art, and FIG. 4A is a graph showing a change in the suctionable volume of the pump according to the embodiment;
(B) is a graph showing a change in a suctionable volume of a conventional pump.

FIGS. 5A and 5B are explanatory diagrams of a flow rate measurement experiment between the pump of Example 1 and a piston pump of the related art. FIG. 5A is an explanatory diagram of a fluid circuit used in this experiment, and FIG. It is a graph of a result.

FIG. 6 is a cross-sectional view of an example in which a sliding ring is made of an elastic material in the pump according to the second embodiment.

FIG. 7 is a sectional view of an example in which a sliding ring is made of an inelastic material in the pump of the second embodiment.

FIG. 8 is a sectional view of a pump according to a third embodiment.

FIG. 9 is a sectional view taken along the line AA in FIG. 8;

FIG. 10 is a sectional view of a pump according to a fourth embodiment.

FIG. 11 is a sectional view of a conventional piston pump.

FIG. 12 is a sectional view of a conventional piston pump.

FIG. 13 is a sectional view of a conventional piston pump.

[Explanation of symbols]

100, 200, 300, 400 ... pump, 104
... 1st cylinder member, 112 ... 2nd cylinder member, 304, 408 ... cylinder, 110, 310
..Suction port (second suction port), 126, 226, 444
... Piston, 128, 450 ... Center hole (first suction port, second discharge port), 136 ... Groove (valve means),
146 ··· Sliding ring (valve means), 152,480
..Discharge chambers (second pump chambers), 154, 478,.
Suction chamber (second pump chamber), 170, 492... Pump chamber (first pump chamber), 192, 498... Discharge port (first discharge port), 404. 2), 406... Discharge path (first discharge port), 458.
..Ring receiving groove (valve means), 460 ... cylindrical member (valve means), 474 ... sliding ring (valve means).

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 1/00-19/24 F04B 23/00-23/04 F04B 53/00-53/22

Claims (1)

(57) [Claims] A first pump chamber having a variable capacity, a first suction port and a first discharge port communicating with the first pump chamber, and increasing and decreasing the volume of the first pump chamber; A first pump mechanism that sucks fluid from the first suction port and discharges fluid from the first discharge port, a second pump chamber, and a second pump chamber that communicates with the second pump chamber. 2
, A second discharge port communicating with the second pump chamber and communicating with the first suction port, and a suction port disposed in the second pump chamber and facing the second suction port. A chamber is formed and a discharge chamber is formed on the second discharge port side, and can be relatively moved along the axial direction with respect to the second pump chamber in synchronization with the increase and decrease of the volume of the first pump chamber. A valve means for interrupting communication between the suction chamber and the discharge chamber when relatively moving to the discharge chamber side, and for communicating the suction chamber and the discharge chamber when relatively moved to the suction chamber side. The second with
When the volume of the first pump chamber is increased, the valve means moves relatively to the discharge chamber side and fluid flows from the second suction port to the suction chamber. And the fluid is filled from the discharge chamber into the first pump chamber via the second discharge port and the first suction port. When the volume of the first pump chamber decreases, Is the first
A pump that discharges a fluid from the discharge port and causes the valve means to relatively move toward the suction chamber to flow the fluid from the suction chamber into the discharge chamber.