JPH0424723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic proportional pressure control valve that supplies pressurized oil at a constant pressure to a hydraulic circuit such as a hydraulic actuator for operating a clutch.

[Prior Art] For example, a normally closed electromagnetic proportional pressure control valve is used in an electronically controlled automatic transmission equipped with a torque converter. -Already proposed by No. 9277.

When controlling the connection operation of the clutch, the seventh
When a command signal current to connect the clutch is applied to the electromagnetic coil of the electromagnetic proportional pressure control valve as shown by line 79 in the figure, the outlet pressure (secondary pressure) applied from the electromagnetic proportional pressure control valve to the hydraulic actuator is 80
a, changes as shown in 80. That is, when the electromagnetic proportional pressure control valve is operated, a pulsating pressure (surge pressure) Ps is generated at the outlet as shown by line 80a, which causes the clutch to become jammed and prevent smooth gear shifting operation. In order to solve the above problem, open the relief valve at a pressure Po+α that is somewhat higher than the normally used outlet pressure Po and release the pulsating pressure Ps to the oil tank.
Hydraulic actuator operates smoothly.

[Problems to be Solved by the Invention] In order to satisfy the above-mentioned requirements, the purpose of the present invention is to eliminate the pulsating pressure that occurs in hydraulically operated equipment due to load fluctuations, and to always supply pressurized oil at a constant pressure to the hydraulically operated equipment. An object of the present invention is to provide an electromagnetic proportional pressure control valve that is integrally equipped with a relief valve so as to supply water to the pressure.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention includes a housing having a drain on one side of the outlet and an inlet on the other side, and an outlet with an axial spacing. A spool having a first annular groove that communicates with the drain and a second annular groove that communicates the outlet with the inlet is fitted, and a spring chamber that communicates with the drain is provided at the drain side end of the housing on the inlet side. In an electromagnetic proportional pressure control valve that has a pilot chamber at each end and controls the pressure in the pilot chamber by an electromagnetic pilot pressure control valve, one end is connected to the drain through a first annular groove inside the spool, and the other end is connected to the pilot chamber. A valve chamber is provided that communicates with each chamber, and the tip of the small diameter portion of a stepped valve body fitted in the valve chamber is biased and engaged with a valve seat on one end side of the valve chamber by a spring force, and a passage is constantly communicated with the outlet. is opened into the peripheral wall of the valve chamber, facing the small diameter portion of the stepped valve body.

[Function] When the electromagnetic coil of the electromagnetic pilot pressure control valve is excited, the valve body of the pilot pressure control valve is pushed by the plunger, and the pressure oil of the hydraulic pump enters the pilot chamber, which is proportional to the excitation current of the electromagnetic coil. This pressure is applied to the end face of the spool of the pressure control valve.

The spool of the pressure control valve resists the spring force and is displaced in proportion to the excitation current of the electromagnetic coil, reducing the pressure of the pressure oil sent from the hydraulic pump to the inlet and supplying it to the hydraulically operated equipment from the outlet.

When pulsations occur in the outlet pressure due to load fluctuations in hydraulically operated equipment, the stepped valve element of the relief valve moves away from the valve seat due to the pulsating pressure, and the pulsating pressure (surge pressure) is released to the oil tank via the relief valve. , does not interfere with the smooth operation of hydraulically operated equipment.

[Embodiments of the Invention] As shown in FIG. 1, the electromagnetic proportional pressure control valve according to the present invention includes a pressure control valve A, an electromagnetic pilot pressure control valve B, an electromagnetic actuator C, and a relief valve D. There is. In the pressure control valve A, a stepped spool 3 having a small diameter part and a large diameter part is fitted into a valve chamber consisting of a small diameter cylindrical part 22 on the left end side of the housing 2 and a large diameter cylindrical part 22a on the right end side. Small diameter cylindrical part 2
A chamber 45 which is closed by the lid 1 at the end of the large diameter cylindrical part 22a and accommodates the spring 4 is provided at the end of the large diameter cylindrical part 22a.
Each pilot chamber 55a is partitioned by a partition plate 70 having a diameter.

The annular groove 7 provided at the boundary between the small-diameter cylindrical portion 22 and the large-diameter cylindrical portion 22a of the valve chamber communicates with a hydraulically operated device M (for example, a hydraulic actuator for operating a clutch of an automatic transmission) via an outlet 36. Large diameter cylindrical part 2
The annular groove 9 provided in 2a communicates with the discharge port of the hydraulic pump P via an inlet 35. The annular groove 6 provided in the small diameter cylindrical portion 22 communicates with the oil tank T via the drain 41.

The spool 3 is pressed against the partition plate 70 by the spring 4 interposed between the left end surface of the spool 3 and the lid 1. At this time, the chamber 45 passes through the cylindrical part of the spool 3, the radial passage 51 or the orifice 5, and the annular groove 6.
Connect to. An annular groove 40 provided on the outer peripheral surface of the small diameter portion of the spool 3 communicates between an annular groove 6 and an annular groove 7 of the valve chamber. The wide annular groove 34 provided on the outer peripheral surface of the large diameter portion of the spool 3 only communicates with the annular groove 9 of the valve chamber, and between the annular groove 7 and the annular groove 9, the spool 3
It is blocked by the land.

As shown in FIG. 2, the relief valve D is constructed inside the spool 3. An annular groove 61 provided at the boundary between the small diameter portion and the large diameter portion of the spool 3 communicates with a radial passage 37, and the passage 37 opens to the circumferential surface of the valve chamber 55 including the valve seat 55b. A cup-shaped stepped valve body 8 having a cylindrical portion 56 is fitted into the valve chamber 55.
The tip of the small diameter portion of the stepped valve body 8 is pressed against the valve seat 55b by the spring 57. Spring 57 of cylindrical portion 56
is interposed between the stepped valve body 8 and the spring seat 60. The spring seat 60 has an orifice 59 and is prevented from moving by a stop ring 10. The left end of the valve chamber 55 communicates with the annular groove 40 through a radial passage 62, and the valve chamber 55 communicates with the annular groove 40 through a radial passage 62.
The right end is the pilot chamber 55 via the orifice 59.
Connects to a.

As shown in FIG. 1, the electromagnetic pilot pressure control valve B is installed in a hollow housing 1 together with a partition plate 70 in a slightly larger diameter cylindrical portion on the right side of the large diameter cylindrical portion 22a.
5 are fitted through the seal members 13 and 16, and the valve body 14 is fitted to the housing 15. An annular groove 42 provided on the circumferential surface of the housing 15 communicates with a discharge port of the hydraulic pump P via an inlet 44 of the housing 2. The annular groove 42 opens through a radial passage 43 into a cylindrical portion of the housing 15 into which the valve body 14 is fitted. The valve body 14 is biased toward the partition wall body 28 by the force of a spring 17 interposed between the housing 15 and the flange 14a of the valve body 14 in the end chamber 31. Two annular grooves 3 provided on the outer peripheral surface of the valve body 14
2 normally contacts the cylindrical surface of the housing 15, but when the valve body 14 moves, it communicates with the passage 43 or the end chamber 31. The two annular grooves 32 include a radial through hole 47, an axial passage 46, and a hole 12 in the partition plate 70.
It communicates with the pilot chamber 55a through. End room 31
communicates with an oil tank T (not shown) via a drain 69 of the housing 2.

The end of the housing 15 is closed by a partition 28 fitted into the housing 2. A hollow plunger 30 having an orifice 27 is fitted into a cylindrical portion provided in the partition body 28 , and a spring 18 is interposed between the left end of the plunger 30 and the valve body 14 . A buffer spring 23 is interposed between the plunger 30, the right end, and the stopper 68.

The plunger 30 is actually fitted into a thin guide cylinder 38 made of a non-magnetic material that is closed by a stopper 68, and a partial cylindrical portion of the partition body 28 and a sleeve 25 having a flange 25a are fitted onto the guide cylinder 38. be done. The winding frame of the electromagnetic coil 19 and the cover 21 are fitted onto the partition wall 28 and the sleeve 25 . The cover 21 is covered by a cap 39 and is provided with a connector 20 in a portion protruding from the cap 39 for connecting a conductive wire drawn out from the electromagnetic coil 19 to an external power source. The electromagnetic coil 19 and the flange 25a of the sleeve 25 are housed inside the cap 39 together with the backing plate 24. Cap 39 is connected to housing 2 by suitable means.

In the relief valve D shown in FIG. 3, a seal member 50 is attached to the outer periphery of the stepped valve body 8 in order to obtain airtightness between the pilot chamber 55a and the valve chamber 55 including the valve seat 55b. The other configurations are the same as those shown in FIG. 2, and similar components are given common reference numerals and explanations are omitted.

FIG. 5 represents an equivalent hydraulic circuit of the electromagnetic proportional pressure control valve shown in FIG. Pressure oil from the hydraulic pump P is sent to the pilot pressure control valve B. Hydraulic pump P
A part of the hydraulic pressure is reduced in accordance with the current of the electromagnetic coil 19, and acts on the spool of the pressure control valve A.
The pressure oil from the hydraulic pump P is reduced in pressure according to the amount of movement of the spool of the pressure control valve A, and is supplied to the hydraulically operated equipment M from the outlet. When pulsating pressure occurs at the outlet of the pressure control valve A with the activation of the hydraulically operated equipment M,
The pulsating pressure is released to the oil tank T via the relief valve D. The relief valve D is operated by the outlet pressure of the pressure control valve A, and frequent opening and closing operations of the relief valve D are suppressed by an orifice 59.

As shown in FIG. 6, an equivalent hydraulic circuit of an electromagnetic proportional pressure control valve can also be represented. That is, the oil pressure of the hydraulic pump P acts on the pilot pressure control valve B through the annular groove 32, and the oil pressure corresponding to the current of the electromagnetic coil 19 acts on the spool of the pressure control valve A. Pressure oil from the hydraulic pump P is reduced in pressure by a pressure control valve A and supplied to a hydraulically operated device M. When pulsations occur in the outlet pressure of pressure control valve A, relief valve D
opens, the pulsating pressure is released to the oil tank T, and the oil pressure supplied to the hydraulically operated equipment M is kept almost constant.

Next, the operation of the electromagnetic proportional pressure control valve according to the present invention will be explained. When the electromagnetic coil 19 of the electromagnetic actuator C is demagnetized, the valve body 14 of the electromagnetic pilot pressure control valve B is in the state shown in FIG.
Pressure oil from the inlet 44 cannot enter the inner cavity of the valve body 14. The pilot chamber 55a has a partition wall 70
hole 12, inner cavity of valve body 14, right annular groove 3
2. It is released to the drain 69 through the end chamber 31. The spool 3 is pressed against the partition plate 70 by the force of the spring 4. The space between the annular groove 9 and the annular groove 7 is closed by the large diameter part (land) of the spool 3,
The outlet pressure of the outlet 36 is 0 (atmospheric pressure).

When the electromagnetic coil 19 of the electromagnetic actuator C is excited, the plunger 30 moves to the left, and the spring 18 pushes the valve body 14 to the left. The pressure oil of the hydraulic pump P flows from the inlet 44 to the annular groove 42 and the passage 4.
3. Annular groove 32 on the left side of the valve body 14, radial passage 47, axial passage 46 (Fig. 4), partition plate 70
It enters the pilot chamber 55a through the hole 12, pushes the spool 3 to the left against the force of the spring 4, and communicates between the annular groove 9 and the annular groove 7 through the annular groove 34.
Pressure oil from the hydraulic pump P enters the inlet 35, the annular groove 9,
It is supplied to the hydraulically operated equipment M via the annular groove 34, the annular groove 7, and the outlet 36. The oil in the chamber 45 flows to the oil tank T via the orifice 5, the annular groove 6, and the drain 41.

At the same time, the pressure oil in the pilot chamber 55a flows through the valve body 14.
to the right against the force of the spring 18 to close both annular grooves 32. In this way, a pressure proportional to the excitation current of the electromagnetic coil 19 is applied to the pilot chamber 55a.

The amount of leftward movement of the spool 3 is the pilot chamber 55a.
The passage area of the annular groove 34 that communicates the annular groove 9 and the annular groove 7 increases in proportion to the pressure of the outlet 3
6 outlet pressure increases.

When pulsating pressure (surge pressure, rapid pressure increase) occurs at the outlet 36 due to load fluctuations in the hydraulically operated equipment M, the pulsating pressure passes through the annular groove 7 and the passage 37 to the valve chamber 55.
and acts on the stepped portion of the stepped valve body 8, causing the stepped valve body 8 to
away from the valve seat 55b. Therefore, the pressure oil at the outlet 36 flows through the annular groove 7, the passage 37, the valve chamber 55, and the passage 6.
2. It flows into the oil tank T via the annular groove 40, the annular groove 6, and the drain 41. In this way, the pulsating pressure at the outlet 36 (indicated by a line 80a in FIG. 6) acts on the stepped valve body 8 of the relief valve D to push it open, and is released to the oil tank T via the drain 41, allowing the hydraulically operated equipment M to operate smoothly. maintain normal behavior.

The right end side of the valve chamber 55 is the orifice 5 of the spring seat 60.
9 to the pilot chamber 55a, the stepped valve body 8 is prevented from operating suddenly, and the outlet pressure is prevented from dropping suddenly.

The operating pressure Po+α of the stepped valve body 8 is set by the area of the stepped portion of the stepped valve body 8 and the pressure in the pilot chamber 55a.

[Effects of the Invention] As described above, the present invention includes a housing having a drain on one side of the outlet and an inlet on the other side.
a first spaced apart from the drain connecting the outlet to the drain;
A spool having an annular groove and a second annular groove communicating the outlet with the inlet is fitted, and a spring chamber communicating with the drain is provided at the drain side end of the housing, and a pilot chamber is provided at the inlet side end. In the electromagnetic proportional pressure control valve which controls the pressure in the pilot chamber by an electromagnetic pilot pressure control valve, one end communicates with the drain through the first annular groove and the other end communicates with the pilot chamber inside the spool. A chamber is provided, and the tip of the small diameter portion of the stepped valve body fitted into the valve chamber is biased and engaged with the valve seat at one end of the valve chamber by a spring force, and a passage constantly communicating with the outlet is connected to the stepped valve body. Since it opens into the peripheral wall of the valve chamber facing the small diameter portion, the following effects are achieved.

(a) The electromagnetic pilot pressure control valve controls the hydraulic pressure in the pilot chamber, and the hydraulic pressure in the pilot chamber drives the spool of the pressure control valve against the spring force, so that the pressure oil at the inlet connected to the hydraulic pump is controlled by the spool. The pressure is reduced to correspond to the amount of movement and is supplied from the outlet to the hydraulically operated equipment. When pulsations occur in the outlet pressure due to load fluctuations on hydraulically operated equipment, a relief valve consisting of a stepped valve body built into the spool opens and releases the pulsating pressure (surge pressure) to the oil tank, so that the hydraulically operated equipment is constantly maintained. Provides smooth operation.

(b) Since the stepped valve body of the relief valve is closed by the hydraulic pressure and spring force in the pilot chamber, the opening pressure of the relief valve changes according to the pressure reduction ratio, and even if the outlet pressure is set high, Frequent opening and closing operations of the relief valve do not occur.

(c) Since the electromagnetic proportional pressure control valve according to the present invention is equipped with a relief valve inside the spool, piping is simple and installation space can be saved. By controlling the excitation current of the pilot pressure control valve, a constant pressure (no pulsating pressure) pressure oil proportional to the excitation current is supplied to the hydraulic actuator, resulting in smooth clutch engagement.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of an electromagnetic proportional pressure control valve according to the present invention, Fig. 2 is a side sectional view of a relief valve in the electromagnetic proportional pressure control valve, and Fig. 3 is a partially modified embodiment of the same relief valve. Fig. 4 is a side view showing the main parts of the pilot pressure control valve;
Figure 6 is an equivalent hydraulic circuit diagram when the electromagnetic proportional pressure control valve according to the present invention is connected to hydraulically operated equipment;
FIG. 7 is a diagram showing the characteristics of a conventional electromagnetic proportional pressure control valve. A...Pressure control valve, B...Pilot pressure control valve, D...Relief valve, M...Hydraulic operating equipment, P
... Hydraulic pump, T ... Oil tank, 2 ... Housing, 3 ... Spool, 8 ... Stepped valve body, 34, 4
0...Annular groove, 35...Inlet, 36...Outlet, 3
7... Passage, 41... Drain, 45... Spring chamber,
55...Valve chamber, 55a...Pilot chamber, 57...
...Spring.

Claims (1)

[Claims] 1 A housing having a drain on one side of the outlet and an inlet on the other side, a first annular groove that communicates the outlet with the drain and a second annular groove that communicates the outlet with the inlet with an axial spacing. A spring chamber communicating with the drain is provided at the drain side end of the housing, and a pilot chamber is provided at the inlet side end, and the pressure in the pilot chamber is controlled by an electromagnetic pilot pressure control valve. In the electromagnetic proportional pressure control valve, a valve chamber is provided inside the spool, one end communicating with the drain through the first annular groove, and the other end communicating with the pilot chamber, and the small diameter of the stepped valve body fitted in the valve chamber is provided. The tip of the part is biased into engagement with the valve seat at one end of the valve chamber by a spring force, and a passage constantly communicating with the outlet opens into the peripheral wall of the valve chamber opposite to the small diameter part of the stepped valve body. An electromagnetic proportional pressure control valve.