2-way cartridge valves with spool position monitoring LFA..E78 (control cover)

Description

• Size 25
• Component series 7X
• Maximum operating pressure 420 bar
• Maximum flow 25000 l/min
• Size 25
• Component series 7X

Features

• Functional product design
• Modular set-up:
  • Cartridge valve with various options
  • Control cover in various variants for realization of selected functions
  • Electric monitoring of the spool position
• Power and flow-optimized design:
  • High flows
  • Low pressure drops
  • High switching velocities
  • Low leakage oil flows

• Robust design:
  • High reliability
  • Long life cycle
• Other features:
  • Small installation size, low weight
  • Easy to service

Product description

2-way cartridge valves are elements that have been designed for a compact block design. The power section with connections A and B is installed into the control block in a receiving hole standardized according to ISO 7368 and closed with a cover. In most cases, the cover is also the connection from the control side of the power section to the pilot control valves.

By control with respective pilot control valves, the power section can be applied for pressure, directional and throttle functions or a combination of these functions. Particularly efficient solutions are realized by adjustment of the size to various flows of the individual ways of an actuator. The application of power sections of elements for multiple functions is very cost-effective.

2-way cartridge valves generally consist of control cover (1) and installation kit (2). The control cover contains the control bores and optionally a stroke limitation function, a hydraulically controlled directional seat valve or a shuttle valve according to the required overall function. Additionally, electrically operated directional spool or seat valves can be installed at a control cover. The installation kit consists of a bushing (3), ring (4) (only up to NG32), valve poppet (5), optionally with damping nose (6) or without damping nose (7) as well as closing spring (8).

The function of 2-way cartridge valves is pressure-dependent. This way, three crucial pressurized areas A1, A2, A3 are realized for the function. The area at valve seat A1 is observed as 100 %. Depending on the version, the annulus area A2 realized by grading is 7 % or 50 % of area A1. The area ratio A1 : A2 is respectively either 14.3 : 1 or 2 : 1. The area A3 is identical to the sum of areas A1 + A2. Due to the different area ratios A1 : A2 and the resulting different annulus areas (A2), the area A3 is one time 107 % and another time 150 % of the area A1 at the seat, which is observed as 100 %.

In general, the following applies:

The areas A1 and A2 are effective in opening direction. The area A3 and the spring are effective in closing direction. The direction of action of the resulting force from the opening and closing forces determines the spool position of the 2-way cartridge valve.

The 2-way cartridge valves can be passed from A to B or from B to A. Pressurization of area A3 by pilot oil discharge from channel B or external pilot oil supply, channel A is blocked without leakage.

Type code

Version
„CA“

Orifice symbol		Symbol in ordering code
A**		A**		This orifice is designed as screw-type orifice. If an orifice is to be installed, the respective code letter with the orifice Ø in 1/10 mm has to be entered in the type designation. Example: A12 = Orifice with Ø1.2 mm in channel A.
Ø1,2				This orifice is designed as bore. No specifications are made in the type designation. (Orifice Ø in mm)
Z12				This orifice is designed as screw-type orifice. This is a standard orifice. No specifications are made in the type designation. (Orifice Ø in 1/10 mm)

Technical data

general

hydraulic

(For applications outside these values, please consult us!)

Diagrams/characteristic curves

(simulated with HLP46, ϑoil = 40±5 °C)

Size 25 (B → A), without damping nose "E"

Nominal size 25 (A → B), without damping nose "E"

Notice:

The indicated characteristic curves have been determined without inserted springs.

Other orifices upon request.

Symbols/Circuit diagrams

LFA . E78…

Electrical connection

Inductive position switch type Q6

The electrical connection is realized via a 4-pole mating connector (separate order) with connection thread M12 x 1.

Connection voltage (DC voltage)	Connection voltage (DC voltage)	V	24
			+30 %/-15 %
Admissible residual ripple		%	≤ 10
Max. load capacity		mA	200
Switching outputs			PNP transistor outputs, load between switching outputs and GND
Pinout	1		+24 V
	2		free
	3		0 V, GND
	4		Switching output: 200 mA

Switching logics

Components

Dimensions

Information

Inductive position switches

Contactless position switches with integrated switching amplifiers are switched shortly before reaching the spool position to be monitored. The spool position reached is displayed by a binary signal.

Advantages of the position switches:

• Short-circuit-proof

• Direct monitoring of the spool position at the control spool. Long life cycle

• High reliability due to no use of dynamic seals

• Reaction time of the switch upon operation approx. 15 ms.

Notice:

Valves with inductive position switches and proximity sensors in safety-relevant controls may only be assembled and commissioned by hydraulically and electrically trained specialists. Service work requires special tools and equipment. This work may only be performed by authorized specialists or in the factory!

Improper work at safety equipment leads to a risk of personal injury and damage to property!

• The valve components are coordinated in the production plant and adjusted during assembly. They must not be interchanged. In case of valve or position switch defects, the complete valve must be exchanged!

• The factory setting of the position switch must not be changed. The position switch may only be set by Bosch Rexroth.

• The position switch must be automatically monitored by the machine control to prevent initiation of a new machine cycle even in case of a defect at the position switch.

Downloads

2-way cartridge valves with spool position monitoring, passively controlled Data Sheet | RE21015 | 2019-07-01 | English | PDF | 2.3MB Product Groups: Logic elements - directional function