JPS63289272A - Hydraulic pump - Google Patents

Abstract

PURPOSE:To avoid the need of a spring for returning a piston by installing a connecting member for always keeping contact of the piston with an eccentric cam, in the constitution in which the piston is moved in reciprocation in a cylinder by the revolution of the eccentric cam. CONSTITUTION:A hydraulic pump is equipped with a pump body 13 in which a cam chamber 14 for accommodating an eccentric cam 18 turned by a motor is formed at the center. A pair of cylinders 22 are arranged oppositely on the both sides of the cam chamber 14. Each piston 24 fitted in slidable manner in each cylinder 22 sucks in the liquid in a reservoir 17 from a suction port 33 through the reciprocating movement interlocked with the turn of the eccentric cam 18, and compresses the liquid and discharging same from a discharge port 44. In this case, each annular groove 28 is formed on the outer periphery of the inner edge part of each piston 24, and a cut recessed part 30 formed at the both edges of a curved connecting plate 29 is fitted into each annular groove 28, and the both piston 24 are connected so as to be always attached to the eccentric cam 18.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a small hydraulic pump that is mounted on, for example, an automobile and generates high pressure.

"Prior Art" Conventionally, a hydraulic pump has been installed in an automobile as a component of an anti-skid device of the automobile. As seen in Japanese Patent Laid-Open No. 58-202142, this conventional hydraulic pump has an eccentric cam 2 provided in the pump body l shown in FIG. The volume of the pressure generation chamber 3a is changed by sliding the piston 4 within the pressure generation chamber 3a, and when the piston 4 is pushed toward the pressure generation chamber 3a by the eccentric cam 2, the liquid pressure within the pressure generation chamber 3a is increased and the discharge valve 5 is is opened against the force of the spring 5a, the liquid in the pressure generating chamber 3a is discharged from the discharge port 6, and then the piston 4 is returned by the force of the spring 3b to increase the volume of the pressure generating chamber 3a. When the internal pressure of the pressure generation chamber 3a becomes negative pressure, the suction valve 7 is opened against the force of the spring 3c, and liquid is sucked into the pressure generation chamber 3a from the suction port 8 and the pressure of this liquid is increased again. This is what I did. In this hydraulic pump, a discharge valve (ball valve) 5 that opens and closes a discharge port 6 is provided in the piston 4, and a suction valve 7 that opens and closes a suction port 8.
and the piston return spring 3b are arranged in series, and the discharge valve 5 and the discharge valve return spring 5a are arranged in series.Furthermore, after the cylinder 3 is assembled into the pump body 1, .

A stopper member 9 is screwed into the pump body 1.

"Problems to be Solved by the Invention" However, in such a conventional hydraulic pump, there is a suction valve (ball valve) 7 on the center line of the cylinder 3. Since the spring 3b for returning the piston, the discharge valve (ball valve) 5, and the spring 5a for returning the discharge valve are arranged in series, there is a drawback that the length of the cylinder 3 in the axial direction becomes long. After the cylinder 3 is assembled into the main body 1, the removal preventing member 9 is further screwed in, so there is a problem that the length in the axial direction becomes even longer.

Further, the spring 3b for returning the piston 4 is required to have a force that allows the return speed of the piston 4 to follow the rotational speed of the eccentric cam 2, and therefore the force of the spring 3b is such a force. However, the force of this spring 3b acts as a resistance force against the operation of the piston when pressure is generated by the hydraulic pump, so this conventional hydraulic pump requires an extra output from the motor than is originally required. There is a problem.

An object of the present invention is to provide a hydraulic pump that solves the above-mentioned problems of conventional hydraulic pumps.

"Means for Solving the Problems" The present invention has the following configuration in order to achieve the above object. That is, a piston is slidably accommodated in a cylinder, and liquid is sucked into a pressure generating chamber formed in the cylinder through a suction chamber from a suction port formed in the cylinder wall and communicating with a reservoir, and the pressure is increased. The liquid in the generation chamber,
Due to the operation of the eccentric cam, the pistons located on both sides of the eccentric cam and in contact with the outer periphery of the eccentric cam reciprocate to compress and generate hydraulic pressure, and the liquid generated by the hydraulic pressure is transferred to the In a hydraulic pump that discharges from a discharge port formed in a cylinder wall, the pistons are connected by a connecting member that keeps the pistons in contact with the eccentric cam at all times.

``Operation'' The pistons on both sides of the eccentric cam are in constant contact with the eccentric cam and operate by following the rotation of the eccentric cam without delay.

This eliminates the need for a spring for returning the piston, shortens the cylinder length, prevents a delay in piston operation, and significantly reduces power loss.

"Embodiment" Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 4. The hydraulic pump of the present invention comprises a motor 11 and a pump section 12, which are generally well known.

Regarding the pump section 12, a cam chamber 14 is provided in the center of the pump body 13. On both sides of the cam chamber 14 in FIG.
A through hole 15.15 is formed perpendicularly to the rotating shaft 11a. Rotation axis l! A extends through the partition wall 13a of the motor 11 on the side of the pump body 13 and faces the cam chamber 14.

Liquid suction passages 16.16 are formed on both sides of the cam chamber 14 and communicate with the through holes 15.15. Passage 16.
16 is communicated with a reservoir 17 shown in FIG. 1 via piping. A liquid is stored in the reservoir 17.

An eccentric cam 18 is fixedly attached to the tip of the rotating shaft 11a of the motor 11. A ring 20 is fitted to the eccentric cam 18 via a bearing 19. 21 is a washer.

Further, each of the through holes 15 and 15 has a cylinder 22.
are fitted, and a suction chamber 23 is formed on the cam chamber 14 side of these cylinders 22. The suction chamber 23 is communicated with the inside of the cylinder 22 through a suction port 33 . A piston 24 is slidably fitted into each cylinder 22 .

A recess 25 is formed in the piston 24 at the bottom side of the cylinder 22, and a stepped cylindrical retainer 26 having a flange 26a is fixed to the opening of the four parts 25 by screwing the flange 26a. A valve chamber 27 is provided in the recess 25.
is formed.

A pair of pistons 24.2 provided on the image side of the ring 20
Annular WIts 28 and 28 are formed on the outer periphery of each of the pistons 24 and 28, respectively, and the pair of pistons 24 and 24 are connected by a connecting plate (connecting member) 29. As shown in FIGS. 3 and 4, this connecting member 29 is a rectangular plate which is curved and bent at both ends, and cutout recesses 30 and 30 are formed at both ends. Notch recesses 30 at both ends of the connecting member 29
゜30 is a pair of pistons 2 as shown in Fig. 1.
4.24, and the piston 24.24 is always kept in contact with the eccentric cam 18 via the ring 20 with a predetermined springiness.

A cylinder chamber 31 is formed between the bottom of the cylinder 22 and the piston 24 and retainer 26. A projection (valve body lift amount regulating body) 26b that projects into the valve chamber 27 is formed at the center of the retainer 26.

Further, the valve chamber 27 can communicate with a suction port 33 formed in the cylinder 22 through a T-shaped passage 32 formed in the piston 24, and a valve seat 34 is provided on the wall of the valve chamber 27 on the passage 32 side.
a is formed.

Also provided within the valve chamber 27 are a suction valve 34 made of a ball valve, and a spring 35 that is loosely fitted into the protrusion 26b and urges the suction valve 34 toward the valve seat 34a. Furthermore, communication holes 36 are formed at four equal positions in the circumferential direction of the retainer 26 to communicate the valve chamber 27 and the cylinder chamber 31. Pressure generation chamber 37
is configured.

On the other hand, an annular groove 38 is formed at a predetermined location on the outer periphery of the cylinder 22, and a discharge chamber 39 is formed between the annular groove 38 and the pump body 13. Moreover, in the cylinder 22,
A discharge port 40 is formed to communicate the pressure generation chamber 37 and the discharge chamber 39. This discharge port 40 is connected to each cylinder 22.2.
One each is formed at two radial positions.

The discharge chamber 39 includes a passage 41 formed in the pump body 13, piping, an actuator (for example, an anti-skid device of an automobile) 42. It is connected to the reservoir 17 via a relief valve 43.

A valve seat 39a made of a spherical seat having a spherical recess is formed in the annular groove 38 of the cylinder 22, located at the opening of the discharge port 40, and this valve seat 39a is made of a ball valve. A discharge valve (valve body) 44 is seated.

The discharge valve 44 is biased and pressed toward the valve seat 39a by a plate spring 45 made of an arcuately curved strip fitted in the annular groove 38, and the discharge port 40 can be opened and closed by the discharge valve 44. It is said that Note that both sides of the leaf spring 45 in the width direction also serve as liquid passages.

Further, seal rings 46° 46 are fitted to the outer periphery of the cylinder 22, located on both sides of the discharge chamber 39 in FIG. It is cut off from the outside world. Further, 47 is also a seal ring.

A hole 48 is formed in the outer end of the cylinder 22 for use with a rotary tool for screwing the cylinder 22 to the pump body 13 during assembly.

Next, the operation of the hydraulic pump configured as described above will be explained.

motor! ! is driven and the rotary shaft 11a rotates, the eccentric cam 18 rotates together with the rotary shaft 11a, and the piston 24 is pushed by the ring 20 via the bearing 19 and reciprocates in its axial direction. Change volume.

When the piston 24 moves to one pressure generation chamber 37 side (the left side of the pressure generation chamber 37 in FIG.
9, the pressure generation chamber 37. Discharge port 40
The liquid inside presses the discharge valve 44 radially outward of the cylinder 22 against the force of the leaf spring 45, opens the discharge valve 44, flows into the discharge chamber 39, and flows into the passage 41. Piping, actuator 42
The water flows into the reservoir 17 via the.

At this time, the suction valve 34 is moved to the valve seat 3 by the force of the spring 35.
4a to close the passage 32, and the spring 35 urges the suction valve 34 against the valve seat 34a.
is not directly changed in deflection by the movement of the piston 24. In addition, as will be described later, a protrusion (valve integrated lift amount regulating body) 26b provided in the valve chamber 27 is connected to the suction valve 34.
Since the lift amount of the suction valve 34 is regulated, the lift amount of the suction valve 34 becomes small, and the spring force of the spring 35 that biases the suction valve 34 becomes almost constant. The force is small, and therefore the suction pressure, ie, the valve opening pressure, is low, and delays in opening and closing of the suction valve 34 are prevented, and the volumetric efficiency of the hydraulic pump is improved.

Further, the plate spring 45 that presses the discharge valve 44 against the valve seat 39a is cut out on both sides in the width direction between its both ends and the opposite side of these ends, so that the leaf spring 45 is wider than the both ends. The area of the curved surface of the leaf spring 45 is considerably reduced compared to using a leaf spring consisting of a strip with a width of 1. The contact area with the liquid is small, the influence of the jet stream ejected from the discharge port 40 on the leaf spring 45 is extremely small, and even when operating at high speed in the liquid, the operating resistance against the liquid is small, This also prevents a delay in the operation of the discharge valve 44.

Further, the discharge valve 44 is fitted into a hole formed in the valve pushing part on the opposite side of both ends of the leaf spring 45, and the discharge valve 44 is held from both sides, and the leaf spring 4
5 and the diameter of the valve pushing part are slightly smaller than the groove width of the annular groove 38, so when assembling the leaf spring 45, the leaf spring 45 does not fall down and the discharge valve 44 is operated. At times, the discharge valve 44 operates linearly on the centerline of the outlet 40. Therefore, since the discharge valve 44 moves the shortest distance, delays in opening and closing the discharge valve 44 are also prevented.

Note that if the hydraulic pressure in the pressure generating chamber 37 is excessive, the pressure generating chamber 37. The liquid in the discharge port 40 flows through the discharge chamber 390 passage 41. It flows into the reservoir 17 through the relief valve 43.

Furthermore, when one of the pistons 24 moves to the left in FIG.
connects the piston 24,24 through the ring 20 to the eccentric cam 1
Since the piston 24 on the right side shown in FIG. 1 also moves in the same direction (to the left side in FIG. 1) as the piston 24 on the left side, the piston 24 on the right side shown in FIG. Liquid is sucked into the chamber 23.

Therefore, according to this embodiment, the piston return spring required in the conventional hydraulic pump can be omitted, and as a result, the force of the piston return spring is applied when the pressure of the hydraulic pump is generated. This acts as a resistance force against the operation of the piston, and can prevent loss of motor output.

One piston (the left piston 24 shown in FIG. 1) 2
4 has moved to the bottom side of one cylinder chamber 31 by the maximum stroke amount, one piston 24 is brought into contact with the ring 20 due to the action of the connecting member 29 that keeps both pistons 24 in constant contact with the eccentric cam 18. At this point, the eccentric cam 18 follows the rotation of the eccentric cam 18 and moves toward the other piston 24, increasing the volume of the one pressure generating chamber 37. Then, the discharge valve 44
is closed, and as the volume of the pressure generation chamber 37 increases, the pressure inside the pressure generation chamber 37 decreases and finally becomes below atmospheric pressure, and the suction valve 34 closes due to the pressure difference between the pressure inside the passage 32 and the pressure inside the pressure generation chamber 37. It leaves the valve seat 34a and opens the passage 32. This allows the passage! 6. Suction chamber 23. Suction port 33
The liquid is sucked into the pressure generating chamber 37 through the first passage 32.

At this time, the discharge valve 44 remains closed, and the protrusion (valve body lift amount regulating body) 26b located in the valve chamber 27 regulates the lift amount of the suction valve 34, so the lift amount of the suction valve 34 is small. The amount of displacement of the spring 35 that biases the suction valve 34 is small and almost constant, and the spring force of the spring 35 is small, so the suction pressure, that is, the valve opening pressure, is low, and the delay in opening the suction valve 34 is prevented. be done.

When the liquid is sucked into the pressure generating chamber 37 and the pressure difference between the pressure generating chamber 37 and the passage 32 disappears, the suction valve 34 is seated on the valve seat 34a by the force of the spring 35.

After this, the piston 24 is further rotated by the eccentric cam 18.
moves to the cylinder chamber 31 side again and compresses the liquid in the pressure generating tube 37.

Note that the discharge valve 44 needs to quickly return to its original state and close the discharge port 40 after the discharge of liquid from the discharge port 40 is finished;
0 opening, that is, the valve seat 39a, to reliably close the discharge port 40. Further, the leaf spring 45 has both ends connected to the cylinder 2.
Since it is engaged with the annular groove 38 of No. 2 so as not to slip, it is always prevented from rotating.

As described above, the suction valve 34 and the discharge valve 44 work alternately as one-way valves and exhibit a pump function. That is, one piston 24 in the pump body 13 and the other piston 2
4, the liquid is sucked in and discharged once for each rotation of the rotating shaft 11a. In the left and right pistons 24 in FIG. 1, the liquid suction and discharge operations are performed in reverse.

The spring force of the connecting member 29 that keeps the pair of pistons 24, 24 in constant contact with the eccentric cam 18 via the ring 20 is sufficient to overcome the sliding resistance force between the piston 24 and the cylinder 22 and the inertia force during high-speed operation. It is necessary to have the strength to overcome this, but if this spring force is too strong, it will only strengthen the force pressing the pair of pistons 24 and 24 against the ring 20 and will not affect anything else. , the motor output will not be lost.

Further, in this embodiment, the spring 35 can be small, and the discharge port 40 is provided in the peripheral wall of the pressure generating chamber 37 of the cylinder 22 perpendicularly to the axial direction of the cylinder 22.
The overall length of the pump body 13 in the axial direction of the pump body 13 is significantly shortened, making the entire hydraulic pump smaller and lighter, requiring less space for installation on a vehicle, and reducing the number of parts, making it easier to assemble them. becomes easier (first
Example).

In the above embodiment, the pair of pistons 24 and 24 are connected by fitting the connecting member 29 into the annular groove 28 formed in each of the pair of pistons 24, but the present invention is not limited to this. As shown in FIG.
8, through holes 51 are formed that penetrate in the diametrical direction, and wire rods 52 are inserted into these through holes 51.51.
A connecting member 53 formed by curving and bending both ends.
The pair of pistons 24 and 24 are connected by inserting both ends of the connecting member 53, and both ends of the connecting member 53 are bent to form a retaining portion 5.
4, the connection member 53 may be prevented from being removed from the pistons 24.24, so that the pair of pistons 24.24 are always kept in contact with the eccentric cam 18 (the above is the second embodiment). .

In addition, the above-mentioned No. 1. In the second embodiment, the pair of pistons 24.24 are connected by fitting or inserting the connecting member 29 or the connecting member 53 into the annular groove 28 or through hole 51 respectively formed in the pair of pistons 24.24. A cylinder (cup) having a bottom portion connected thereto, for example, but not limited to, as shown in FIGS. 6 to 8.
A T-shaped notch 62 is formed on the outer periphery of the piston 61, and this notch 62 is connected to the pair of pistons 24 and 24 as in the first embodiment.
The pistons 24, 24 may be fitted into an annular WII 28 formed on the side end of the eccentric cam 18, so that the pair of pistons 24, 24 are always kept in contact with the eccentric cam 18.

That is, a circular hole 63 is formed at the bottom of the cylinder 6I, and the cylinder 6I has a circular hole 63 formed at the bottom.
Both cut hole portions 62 and 62 on the outer periphery of the ring 1 press the pair of pistons 24 and 24 against the ring 20 with a predetermined springiness (the above is the third embodiment).

Further, in each of the above embodiments, the washer 2 is attached to the flange wall of the eccentric cam 18 having a flange and the rotating shaft 11a of the motor 11! Although the bearing 19 is interposed between the bearing 19 and the wall, the present invention is not limited to this, and the structure may be configured as shown in FIGS. 9 to 15, for example. That is, an eccentric cam 71 that is straight in the axial direction without a cylindrical flange and has a shaft hole is attached to the rotating shaft 11a of the motor it.
are screwed together and fixed without a washer.

In addition, at the end of the outer periphery of the eccentric cam 71, as shown in FIGS.
As shown in the figure, a chamfer (tool hook) 72 is formed on the eccentric cam 71 for hooking a tool when the eccentric cam 71 is screwed and fixed to the rotating shaft 11a.

Further, a ring 74 having a bearing 73 inserted therein is fitted to the outer periphery of the eccentric cam 71 so as to be slidable in the axial direction of the eccentric cam 7I. Then, an annular groove 75 shown in FIGS. 1O and 11 or a parallel groove (chamfered part) 76 shown in FIGS. piston 24.24
The ends on the eccentric cam 71 side are brought into contact with each other. A side wall 77 of the annular groove 75 or a side wall 78 of the parallel groove 76 restricts movement of the ring 74 in the axial direction with respect to the piston 24. Note that the bearing 73 may be a needle bearing or a bush type bearing.

According to this embodiment, the axial length of the bearing 73 can be made as long as the axial length of the eccentric cam 71 to expand the pressure receiving area, so that the pair of pistons 24.2
Even if the ring 74 and the bearing 73 undergo rapid and large load fluctuations due to the hydraulic pressure generated by the movement of the eccentric cam 18 of the first embodiment, the load on the bearing 73 can be reduced. It is possible to prevent the occurrence of friction 1 heat generation due to contact with the washer 21, and the rotating shaft 11a, the eccentric cam 71. Bearing 73° Ring 74
It has the advantage that the durability of the bearing 73 can be improved without increasing the size of the bearing 73, a small hydraulic pump with a long life can be provided, and the washer 21 can be omitted (see the fourth example above). Example).

"Effects of the Invention" According to the present invention, a piston is slidably housed in a cylinder, and pressure is generated in the cylinder through a suction chamber from a suction port formed in a cylinder wall and communicating with a reservoir. Liquid is sucked into the pressure generation chamber, and the liquid in the pressure generation chamber is compressed by the reciprocation of the pistons located on both sides of the eccentric cam and in contact with the outer periphery of the eccentric cam by the operation of the eccentric cam. In a hydraulic pump that generates pressure and discharges the liquid with the generated hydraulic pressure from a discharge port formed in the cylinder wall, the piston is held in contact with the eccentric cam by a connecting member that constantly maintains the piston in contact with the eccentric cam. Because they are connected, the total length of the pump body in the axial direction of the cylinders is significantly shortened, making the entire hydraulic pump smaller and lighter, requiring less space for installation on the vehicle, and reducing the number of parts. Assembling them is easy, and the pistons on both sides of the eccentric cam are connected by a connecting member, and this connecting member can always keep the piston in contact with the eccentric cam with a predetermined springiness.
The pistons on both sides of the eccentric cam can be forcibly operated by the rotation of the eccentric cam. This eliminates the need for a spring for returning the pistons, which is required in conventional hydraulic pumps, and reduces the delay in piston operation. This prevents the piston from colliding with the eccentric cam and causing noise due to a delay in piston operation, and prevents damage to the contact surface between the piston and the eccentric cam, as well as improving liquid suction efficiency. Conventionally, the force of the spring for returning the piston acts as a resistance force against the operation of the piston when pressure is generated by the hydraulic pump, and this loss of motor output can be prevented. ,
Overall performance can be significantly improved.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention,
Fig. 1 is a sectional view taken along line Ii in Fig. 2, Fig. 2 is a partially cutaway cross-sectional plan view, Fig. 3 is a longitudinal sectional view of the connecting member, Fig. 4 is a side view of the connecting member, and Fig. 5 6 is a cross-sectional view of the main part of the second embodiment of the present invention, and FIGS. 6 to 8 are a cross-sectional view of the main part of the third embodiment of the present invention. FIG. 8 is a vertical cross-sectional side view of the connecting member, FIG. 8 is a view taken from the ■ arrow in FIG. 7, FIGS. 9 to 15 show a fourth embodiment of the present invention, and FIG. , Figure 1O is a side view of the ring,
Fig. 11 is a front view of the ring, Fig. 12 is a side view of the ring, Fig. 13 is a sectional view taken along the line ■-■ in Fig. 12, and Fig. 14 is a cross-sectional view of the ring.
The figure is a side view of the eccentric cam, and Figure 15 is a front view of the eccentric cam.
FIG. 16 is a vertical cross-sectional view of the main parts of an example of a conventional hydraulic pump. 11... Motor, lla... Rotating shaft,
12...Pump part, 13...Pump body, 14...Cam chamber, ■7...Reservoir, 18.71...Eccentricity Cam, 22...
・Cylinder, 23... Suction chamber, 24...
...Piston, 29...Connection plate (connection member),
33...Suction port, 34...Suction valve, 37...Pressure generation chamber, 39...Discharge chamber, 40...Discharge port , 44...Discharge valve, 53...Connection member.

Claims (1)

[Claims] A piston is slidably accommodated in the cylinder, and liquid is sucked into a pressure generation chamber formed in the cylinder through a suction chamber from a suction port formed in the cylinder wall and communicating with a reservoir, and the liquid is sucked into the pressure generation chamber formed in the cylinder. The liquid is compressed by the reciprocation of the pistons located on both sides of the eccentric cam and in contact with the outer periphery of the eccentric cam due to the operation of the eccentric cam, thereby generating hydraulic pressure. A hydraulic pump that discharges liquid from a discharge port formed in the cylinder wall, characterized in that the piston is connected by a connecting member that keeps the piston in contact with the eccentric cam at all times.